Article
To read the full-text of this research, you can request a copy directly from the authors.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Semi-quantitative procedures for structure evaluation using visual and tactile assessment are receiving increased attention , notably regarding impacts of current agricultural practices (Batey, 2009), reduced tillage strategies and agri-environmental considerations (Newell-Price et al., 2012). Soil quality has been visually assessed informally for millennia (Batey, 2000); however, visual soil evaluation (VSE) techniques (Ball & Munkholm, 2015) offer repeatable procedures for examining structural morphology for soil quality assessment (Mueller et al., 2013). Correlations between VSE techniques and quantitative soil measurements have been widely described (McKenzie, 2001;Mueller et al., 2009;Pulido Moncada et al., 2014a) including indicators of soil physical quality Pulido Moncada et al., 2014b) and bio-chemical quality (da Silva et al., 2014;Askari et al., 2015). ...
... SubVESS is an adapted version of VESS for subsoil assessment (Ball et al., 2015) with an emphasis on identifying anthropogenic impacts on transition layers or compacted pans. Using a soil pit to 1.4 m, soil layers are identified and assessed separately for mottling, strength, porosity, rooting and aggregate characteristics. ...
... Both visual inter- (Werner & Th€ amert, 1989;Shepherd, 2000) and intra- (Guimarães et al., 2011) aggregate porosity are examined. Exploring profile faces with a knife reveals macro-pores (Ball et al., 2015), which can be highlighted with diluted paint (McKenzie, 1998). The quantification of earthworm burrows is also employed (Munkholm, 2000;Peign e et al., 2013). ...
Article
Soil structure forms a key component of soil quality, and its assessment by semi-quantitative visual soil evaluation (VSE) techniques can help scientists, advisors and farmers make decisions regarding sampling and soil management. VSE techniques require inexpensive equipment and generate immediate results that correlate well with quantitative measurements of physical and biochemical properties, highlighting their potential utility. We reviewed published VSE techniques and found that soils of certain textures present problems and a lack of research into the influence of soil moisture content on VSE criteria. Generally, profile methods evaluate process interactions at specific locations within a field, exploring both intrinsic aspects and anthropogenic impacts. Spade methods focus on anthropogenic characteristics, providing rapid synopses of soil structure over wider areas. Despite a focus on structural form, some methods include criteria related to stability and resiliency. Further work is needed to improve existing methods regarding texture influences, on-farm sampling procedures and more holistic assessments of soil structure.
... The Visual Evaluation of Soil Structure (VESS; Ball et al., 2007) test was reimagined from the Peerlkamp method, based on discussions held at the meeting in Peronne, France, in 2005. The SubVESS method (Ball et al., 2015) was inspired by discussions on the need for a subsoil evaluation method during the Edinburgh, UK (2009) and Aarhus, Denmark (2011) meetings. The interest in VSE has grown in recent years, resulting in the refinement of methods and the adaption of methods to different pedological and climatic conditions, as well as in utilizing VSE methods together with qualitative methods to evaluate the impact of soil management (Munkholm et al., 2013). ...
... The field days gave the participants access to different soils, crops and management systems, which permitted the demonstration of the various VSE methods under diverse scenarios and conditions. Five methodologies (VESS (Guimarães et al., 2011), VSA (Shepherd, 2009), SOILpak (McKenzie, 2001, SubVESS (Ball et al., 2015) and Profil Cultural − French and Brazilian versions, (Peigné et al., 2013;Tavares Filho et al., 1999)) were tested in Oxisols with contrasting textures. On the first day, the group visited a sugarcane field on an Oxisol with approx. ...
... By comparing the native forest to the cultivated area it was possible to reveal the depth to which anthropogenic modification of the soil had occurred. A particular highlight of the field days was the demonstration of the SubVESS methodology http://dx.doi.org/10.1016/j.still.2017.03.011 (Ball et al., 2015) to the VSEE community for the first time. The field days allowed the delegates to explore the use of both topsoil and subsoil methods for visual assessment under tropical soils, and to discuss subsoil compaction prevention strategies for tropical soils. ...
... Concern over subsoil structural degradation and associated impacts led to the development of SubVESS (Ball et al., 2015a) to compliment VESS and allow assessment of a soil profile to 1 m depth, using a simple flowchart and numeric scores (Ball et al., 2015a;Ball et al., 2017). As with other profile methods, SubVESS follows classical soil survey principles, though emphasises anthropogenic impact assessment, concentrating on the transition layer (Ball et al., 2015a), the zone between the topsoil and subsoil, often directly below the deepest, regular cultivation operation and particularly prone to compaction in arable soils (Peigné et al., 2013). ...
... Concern over subsoil structural degradation and associated impacts led to the development of SubVESS (Ball et al., 2015a) to compliment VESS and allow assessment of a soil profile to 1 m depth, using a simple flowchart and numeric scores (Ball et al., 2015a;Ball et al., 2017). As with other profile methods, SubVESS follows classical soil survey principles, though emphasises anthropogenic impact assessment, concentrating on the transition layer (Ball et al., 2015a), the zone between the topsoil and subsoil, often directly below the deepest, regular cultivation operation and particularly prone to compaction in arable soils (Peigné et al., 2013). ...
... Concern over subsoil structural degradation and associated impacts led to the development of SubVESS (Ball et al., 2015a) to compliment VESS and allow assessment of a soil profile to 1 m depth, using a simple flowchart and numeric scores (Ball et al., 2015a;Ball et al., 2017). As with other profile methods, SubVESS follows classical soil survey principles, though emphasises anthropogenic impact assessment, concentrating on the transition layer (Ball et al., 2015a), the zone between the topsoil and subsoil, often directly below the deepest, regular cultivation operation and particularly prone to compaction in arable soils (Peigné et al., 2013). SubVESS assesses features at particular sampling locations and for wider spatial coverage, for example, comparison between field areas, the excavation of multiple pits is required (Ball et al., 2015a). ...
... In this context, researchers have begun to look more systematically at subsoil functions/the role of subsoil for soil functions and to develop and investigate new strategies of mechanically or biologically intervening in subsoils that aim to tap the subsoil as a resource [10][11][12][13][16][17][18]]. Yet how relevant, feasible, and acceptable are different methods for subsoil management as a strategy that can contribute to the sustainable management of soils and to securing long-term agricultural yields? ...
... While deep ploughing was once quite popular in Germany, and often applied on organic rich soils (peatland) (No. 6, No. 13), it is no longer practiced widely in Germany. Detrimental effects to soil structure, soil functions and soil life (2,4,5,6,7,8,16,17) Heavy machines necessary and lots of energy (3,6,8,10,11,12) In no case acceptable (1,2,3,4) Numbers in parentheses indicate the No. of stakeholders and farmers who mentioned the respective aspect. ...
... Suitable for heavily compacted sites, primarily under driving lanes and headlands (1,2,3,4,5,7,11,12,13,14,18) Risk of re-compaction, complete loss of soil structure or shift compaction into deeper layers (2,5,7,10,16,17) Accepted on dry soils/ light and sandy (1,2,10,12,13,16,18) High efforts and costs, heavy machineries and high energy input is needed (3,6,7,8,10,12,15) Only in combination with biological activation, catch cropping or diverse crop rotation (2,4,6,7,10,12,18) Not suitable for subsoils with stones and drainage systems (14,15) Short-sighted solution, without implementing any changes in the farming system that aim to prevent new compaction, lead to the need to repeat the procedure again after a short period of time (1,5,6,7) Subsoiling requires heavy machinery and a high input of energy to loosen deep soil layers, making it an intense operation that involves high efforts and costs. One rather sceptical farmer therefore described the technique as a "gigantic technological effort" with rather marginal results (No. 10). ...
Article
Full-text available
Subsoil, commonly defined as horizons below the working depth of 30 cm, has traditionally received little explicit attention in policy discussions on soils. Recently, however, there has been growing recognition among scientists of the issues of subsoil (re-)compaction and of the role of subsoil as a resource that can offer valuable nutrients and water for plants. Subsoil management could provide an option to sustainably maintain yields in the context of climate change and resource scarcity, and it is a central question in addressing subsoil compaction. Yet how socially acceptable are different methods for subsoil management? Drawing on in-depth interviews with farmers and stakeholders in Germany, we show that biophysical conditions, the timing of operations, economic considerations, and awareness of subsoil functions are key factors in the acceptance of management methods. Views towards methods involving mechanical intervention are more diverse and in some cases more critical because the benefits are not always certain, the costs can outweigh the benefits, and/or because they entail risks for soil structure and functions. Alfalfa cultivation is seen to be beneficial for yields without risks for soil structure and functions; however, economic barriers limit its uptake. Awareness of multiple subsoil functions is associated with more critical views of mechanical interventions.
... SubVESS ; (iii) topsoil and subsoil together such as SOILpak (McKenzie, 2013), 'Profil Cultural' (Peigné et al., 2013) and (iv) assessments that describe and measure more than soil structure such as the complete VSA analysis (Shepherd, 2009) and the Mueller Soil Quality Rating (M-SQR) (Mueller et al., 2013). A recent special issue of Soil & Tillage Research (Munkholm et al., 2013a) and book (Ball and Munkholm, 2015) summarised common methods of visual soil evaluation and their application to crop production, land appraisal, soil quality, soil compaction and the wider environment. ...
... A more progressive assessment of individual visual and tactile aspects such as used in SubVESS may be worthwhile for topsoil VESS, particularly when used for research purposes. A better description of porosity to reflect the importance of its contribution to drainage, aeration and root growth and of fragment stability to distinguish intensively tilled soils from stable aggregates would be useful to extend the role of VESS to better reflect agronomic limitations (Ball and Munkholm, 2015). For example, the human eye can usually see objects down to c. 20 mm diameter. ...
... Ideally we recommend that the validity of such thresholds to inform soil management is supported by other soil quality data such as bulk density, resistance to penetration, macroporosity or infiltration rates and by soil biological and yield data. Alternatively, other visible features could be used, such as evidence of waterlogging, decrease in yield or evidence of crop stress, rooting depth, surface relief (Shepherd, 2009;Ball et al., 2015). For example, in Brazil, in some areas under long-term no-tillage (>10 yr), Sq 4 clods were found throughout the topsoil, based on resistance to break up, in heavy clay soils. ...
... Soil structure can be assessed visually with the trench or profile method (McKenzie, 2013;Boizard et al., 2017) or the shovel method (Shepherd, 2000;Ball et al., 2007Ball et al., , 2015Guimarães et al., 2011;Ralisch et al., 2017;Emmet-Booth et al., 2018). The trench and profile methods require much technical knowledge, time and financial resources (Tavares Filho et al., 1999;Cui et al., 2014). ...
... Questions 3-8 were objective but only one answer could be given to Q3-Q6, while it was possible to choose more than one answer to Q7 and Q8. Questions 7-9 concerned the following six methods: Peerlkamp Test (Peerlkamp, 1959); Cultural Profile (Henin et al., 1969;Gautronneau and Manichon, 1987;Tavares Filho et al., 1999); Visual Soil Assessment (VSA) (Shepherd, 2000); Visual Evaluation of Soil Structure (VESS) (Ball et al., 2007;Guimarães et al., 2011); Análise Subsoil Visual Evaluation of Soil Structure (SubVESS) (Ball et al., 2015); and Diagnóstico Rápido da Estrutura do Solo [Fast Diagnosis of Soil Structure] (DRES) (Ralisch et al., 2017). ...
... Because soil use and cultivation management problems may appear throughout intense cultivation (Lal, 2018). Few previous studies have used the SubVESS method in Brazil, and all have been restricted to the Southern and Southeastern regions (Ball et al., 2015(Ball et al., , 2017Guimarães et al., 2017aGuimarães et al., , 2017b. No previous study has used the Peerlkamp Test, probably because the shovel methods currently used are easier and detect soil changes more accurately than the Peerlkamp Test (Shepherd, 2000;Ball et al., 2007Ball et al., , 2015Guimarães et al., 2011;Ralisch et al., 2017). ...
... Concern over subsoil structural degradation and associated impacts led to the development of SubVESS (Ball et al., 2015a) to compliment VESS and allow assessment of a soil profile to 1 m depth, using a simple flowchart and numeric scores (Ball et al., 2015a;Ball et al., 2017). As with other profile methods, SubVESS follows classical soil survey principles, though emphasises anthropogenic impact assessment, concentrating on the transition layer (Ball et al., 2015a), the zone between the topsoil and subsoil, often directly below the deepest, regular cultivation operation and particularly prone to compaction in arable soils (Peigné et al., 2013). ...
... Concern over subsoil structural degradation and associated impacts led to the development of SubVESS (Ball et al., 2015a) to compliment VESS and allow assessment of a soil profile to 1 m depth, using a simple flowchart and numeric scores (Ball et al., 2015a;Ball et al., 2017). As with other profile methods, SubVESS follows classical soil survey principles, though emphasises anthropogenic impact assessment, concentrating on the transition layer (Ball et al., 2015a), the zone between the topsoil and subsoil, often directly below the deepest, regular cultivation operation and particularly prone to compaction in arable soils (Peigné et al., 2013). ...
... Concern over subsoil structural degradation and associated impacts led to the development of SubVESS (Ball et al., 2015a) to compliment VESS and allow assessment of a soil profile to 1 m depth, using a simple flowchart and numeric scores (Ball et al., 2015a;Ball et al., 2017). As with other profile methods, SubVESS follows classical soil survey principles, though emphasises anthropogenic impact assessment, concentrating on the transition layer (Ball et al., 2015a), the zone between the topsoil and subsoil, often directly below the deepest, regular cultivation operation and particularly prone to compaction in arable soils (Peigné et al., 2013). SubVESS assesses features at particular sampling locations and for wider spatial coverage, for example, comparison between field areas, the excavation of multiple pits is required (Ball et al., 2015a). ...
Article
Visual soil evaluation (VSE) techniques, established in soil management and quality assessment are categorised into spade and profile methods. Both approaches have merits and limitations. For example, VESS, a widely used spade method, requires basic equipment and is quick, thereby enabling wide spatial deployment, but only gives a general indication of soil structural quality to 25 cm depth, potentially missing important features below the cultivation zone in arable soils. SubVESS, the profile equivalent of VESS, gives detailed information to ≈ 1 m at specific points but is time consuming, relatively expensive and cannot be deployed over wide areas. Despite giving more detailed information, full (to ≈ 1 m) profile methods may not always be desirable. Our aim was to compare possible management recommendations derived from soil structure, obtained by VESS, SubVESS and a new procedure that bridged both approaches, called the Double Spade method (DS). In-field and headland zones at 10 arable sites in Ireland under conventional tillage were surveyed using the methods, assessing to ≈ 25 (VESS), 40 (DS) and 80 (SubVESS) cm depth respectively. Results showed significant difference between field zones, indicating structural damage at headlands, occasionally to 80 cm depth. From the soils surveyed, VESS was not always sufficient for determining soil quality related management requirements. DS indicated that damage occurred below 20 cm depth. SubVESS gave additional information to the other VSE techniques regarding the extent of damage, in some cases only evident below 40 cm depth. Quantitative measurements showed significant difference only to 20 cm depth. It was concluded that the extra information obtained using DS was worth the time spent collecting the data. It is suggested that SubVESS may be appropriate to further investigate suspected issues as indicated by DS, but not for routine survey over large areas.
... The visual evaluation of subsoil structure (SubVESS) method of Ball et al. (2015) was applied on 16 soil profiles (four treatments x four blocks). The upper and lower depth limits of assessment were below 20 cm and to approximately 1 m, respectively. ...
... Scoring of the indicators is based on a scale of 1-5, where 1 is best and 5 is worst. The overall score of the subsoil structural quality (Ssq) is based on the score of the five indicators and the SubVESS description given in the flowchart (Ball et al., 2015). ...
... At 30 cm depth, the d eff was significantly smaller for M8 (66 μm) than for M3 (110 μm) and S12 (104 μm (Ball et al., 2015). Standard deviation is given in parenthesis ( ± ). ...
Article
Traffic in agricultural fields with very high wheel loads imposes a risk of severe structural damage deep into the subsoil. However, there is a paucity of studies quantifying these effects. This study focuses on heavy traffic-induced changes in soil structure for a sandy loam soil in a temperate region. The treatments included no compaction (Control), compaction with ∼3 Mg (M3) and ∼8 Mg (M8) wheel loads with multiple (4–5) wheel passes, and compaction with a single-pass wheel load of ∼12 Mg (S12). The compaction treatments were replicated four consecutive years. Subsoil structural quality was evaluated visually by the SubVESS method, and soil pore characteristics were quantified for minimally disturbed soil cores sampled at 30, 50, 70 and 90 cm depth two years after the end of the experiment. Our results indicate that M8 significantly affected soil structural properties to >50 cm depth in terms of reduced subsoil structural quality, air-filled pore space, air permeability, gas diffusivity, pore volume and increased bulk density. Results also showed that the degree of compactness was ≥95% for M8 at 30 and 50 cm depth. Even though a pre-existing dense soil matrix was described in the studied soil, results confirmed that high wheel loads may cause significant subsoil compaction at >50 cm depth. Surprisingly, the S12 treatment did not show marked signs of decreasing structural quality at depth. Thus, our results indicate that primarily traffic applying multiple passes with high wheel loads compromises soil structure at depth. The S12 results further suggest the need to investigate the influence of factors other than wheel load and inflation pressure on the risk of subsoil compaction.
... Later in its meeting in 2011, an adaptation of the VESS method was developed for the numerical assessment of any anthropic structural deformation of the transition layer and identification of subsoil compaction. The subsoil structural quality assessment, called SubVESS, was then published by Ball et al. (2015). The main purpose of the SubVESS was to identify the requirement for subsoil compaction mitigation practices and the depth at which these are needed. ...
... The key criteria used in SubVESS include drainage status, as well as cracking and biopores as essential soil characteristics for gas transport and pathways for roots in the subsoil. Ball et al. (2015) applied the method in soils of contrasting compaction status under a temperate and tropical climate, as well as in soils of contrasting types in a temperate climate. The authors showed that SubVESS could identify subsoil quality under diverse conditions. ...
... Pulido- Moncada et al. (2019) found that SubVESS detected signs of increased compaction after multiple passes of heavy traffic on temperate sandy loam soil, reflecting a diminution of effectiveness of macroporosity found from pore characterisation conducted in the laboratory. However, Ball et al. (2015) recognised that the method did not assess the water-holding capacity, which is a factor of importance in stony soils and Vertisols, for which systems such as the SOILpak or the Profile Cultural are more suitable. ...
Chapter
Soil structure is a complex and dynamic soil property that constitutes a key aspect of soil health. Soil structure assessment can be evaluated in the field by visual soil evaluation techniques. Development and improvement of these techniques/methods have been the focus of numerous soil scientists worldwide since the mid-20th century. Divided into topsoil and soil profile methods, they differ in principle and level of detail of the assessment. The development and protocols of selected methods are presented in this chapter in chronological order of development, to show differences in methodological approaches. The description given for each of the methods includes guidance for the appropriate selection of the method to be used by stakeholders. Two case studies are given as examples of i) how visual techniques can contribute to achieving the challenges for developing sustainable agricultural management focused on nurturing soil fertility, and ii) the use of visual techniques as tools to assess and monitor soil health in developing countries.
... Observing the structure of a soil down to a depth of 0.6-1m is important, particularly where anthropic subsoil damage is suspected ( Fig. 1.9). Such observation will allow diagnosis of most of the structural problems of agricultural soils and can be done using the SOILpak and SubVESS methods (McKenzie, 2001;Ball et al., 2015). There is usually a significant variation in soil structure with depth. ...
... The situation described above can be more complicated if the texture varies with depth. In such situations, it may be necessary to seek more layers (e.g. using SubVESS, Ball et al., 2015) as a function of both the agricultural activity and the pedogenetic horizons. On the other hand, when the soil has a good structure, it is more usual to see only two layers, that is, the tilled layer and the layer below. ...
... When the soil is very anaerobic it also smells bad, like rotten eggs, due to the production of reduced sulfur gases. Evaluation of soil aeration status is integrated as part of many visual evaluation methods such as VSA (Shepherd, 2009), VESS and SubVESS (Ball et al., 2007;Ball et al., 2015). ...
Chapter
This book with nine chapters describes the main methods for visual soil evaluation (VSE) of soil structure and soil-related properties. It includes clear visual images of the variation of soil quality and how these relate to soil productivity and environmental sustainability. Such images raise awareness and provide a measure of the soil degradation that is a looming threat to the viability of world agriculture. Emphasis is given to recognizing, protecting and restoring soil quality as these are of vital importance for tackling problems of food insecurity, global change and environmental degradation. The book shows how these aims can be achieved with VSE by describing tools that can readily be used by land users and environmental authorities to assess crop performance, soil improvement and soil productivity. VSE is also placed in the context of future sustainable intensification of agriculture including factors of soil loss, resilience, climate change, scarcity of water and other resources, nutrient retention and increased risk of degradation. This book is relevant not only to students, lecturers, scientists and advisors working directly with soils but also to policy makers, food security experts, environmentalists and engineers who have an interest in soils and sustainable agricultural production. Last, but not least, it is hoped that these simple VSE techniques will be used extensively in years to come as a tool to link soil specialists and non-specialists together with the mutual aim of developing sustainable soil management to advance global food security and improve the environment.
... Compaction, mostly caused by machinery traffic, decreases water and nutrient availability and changes the biochemical environment, which can lead to intensive denitrification and nitrous oxide emission contributing to the greenhouse effect. Subsoil compaction is an increasing threat to future agriculture due to the use of increasingly heavier machinery and overexploitation of soil (Jones et al., 2003;Ball, 2013;Ball et al., 2015). ...
... SOILpak (McKenzie) and le profil cultural (Peigné et al., 2013) can reveal soil quality for the whole profile; the latter shows the spatial variability of soil structure (see Chapter 2). Most of these methods have been developed under temperate conditions, although they have been shown to work well on tropical soils Guimarães et al., 2013;Moncada et al., 2014;Ball et al., 2015). SOILpak and VSA have been tested in a wide range of soils (see Batey et al.,Chapter 2, this volume for more details of these methods). ...
... Le profil cultural has also been developed under temperate conditions; however, studies such as Tavares Filho et al. (1999) have shown its adaptability to tropical soil conditions. Figure 8.8 shows the use of the le profil cultural and SubVESS methods to detect compacted layers, demonstrating the value of these methods in tracking soil degradation ( Tavares Filho et al., 1999;Peigné et al., 2013;Ball et al., 2015). ...
Chapter
This book with nine chapters describes the main methods for visual soil evaluation (VSE) of soil structure and soil-related properties. It includes clear visual images of the variation of soil quality and how these relate to soil productivity and environmental sustainability. Such images raise awareness and provide a measure of the soil degradation that is a looming threat to the viability of world agriculture. Emphasis is given to recognizing, protecting and restoring soil quality as these are of vital importance for tackling problems of food insecurity, global change and environmental degradation. The book shows how these aims can be achieved with VSE by describing tools that can readily be used by land users and environmental authorities to assess crop performance, soil improvement and soil productivity. VSE is also placed in the context of future sustainable intensification of agriculture including factors of soil loss, resilience, climate change, scarcity of water and other resources, nutrient retention and increased risk of degradation. This book is relevant not only to students, lecturers, scientists and advisors working directly with soils but also to policy makers, food security experts, environmentalists and engineers who have an interest in soils and sustainable agricultural production. Last, but not least, it is hoped that these simple VSE techniques will be used extensively in years to come as a tool to link soil specialists and non-specialists together with the mutual aim of developing sustainable soil management to advance global food security and improve the environment.
... SubVESS ; (iii) topsoil and subsoil together such as SOILpak (McKenzie, 2013), 'Profil Cultural' (Peigné et al., 2013) and (iv) assessments that describe and measure more than soil structure such as the complete VSA analysis (Shepherd, 2009) and the Mueller Soil Quality Rating (M-SQR) (Mueller et al., 2013). A recent special issue of Soil & Tillage Research (Munkholm et al., 2013a) and book (Ball and Munkholm, 2015) summarised common methods of visual soil evaluation and their application to crop production, land appraisal, soil quality, soil compaction and the wider environment. ...
... A more progressive assessment of individual visual and tactile aspects such as used in SubVESS may be worthwhile for topsoil VESS, particularly when used for research purposes. A better description of porosity to reflect the importance of its contribution to drainage, aeration and root growth and of fragment stability to distinguish intensively tilled soils from stable aggregates would be useful to extend the role of VESS to better reflect agronomic limitations (Ball and Munkholm, 2015). For example, the human eye can usually see objects down to c. 20 mm diameter. ...
... Ideally we recommend that the validity of such thresholds to inform soil management is supported by other soil quality data such as bulk density, resistance to penetration, macroporosity or infiltration rates and by soil biological and yield data. Alternatively, other visible features could be used, such as evidence of waterlogging, decrease in yield or evidence of crop stress, rooting depth, surface relief (Shepherd, 2009;Ball et al., 2015). For example, in Brazil, in some areas under long-term no-tillage (>10 yr), Sq 4 clods were found throughout the topsoil, based on resistance to break up, in heavy clay soils. ...
Article
Visual soil evaluation techniques have gained popularity and are increasingly used in agriculture and soil science for research, consultancy and teaching purposes. We describe recent applications, developments, opportunities and limitations, mainly of the Visual Evaluation of Soil Structure (for topsoil (VESS) and for subsoil (SubVESS)), and of the Visual Soil Assessment (VSA). Data are taken from experiments on compaction and from assessments made in farmer’s fields in the UK, Brazil and New Zealand. The methods are widely used to detect compaction and are well-suited for monitoring changes in compaction status, particularly in relation to weather extremes. VESS proved useful in distinguishing grazing vs wheel compaction in the UK and Brazil by permitting detection of layers at different depths within the topsoil zone. The depths of compact layers are important for scoring management decisions for soil improvement. However the use of scores as limiting thresholds in different soil types needs the support of further soil measurements and/or additional visual assessments of soil and crop. VSA and VESS were also used to estimate the risk of significant soil emissions of nitrous oxide where compaction damage was present and rates of mineral N fertiliser were high. Visual assessments also have the potential to assess the risk of surface water runoff and nutrient loss. The potential role of soil colour was shown for the further development of visual evaluation techniques for a soil carbon storage index. Visual soil evaluation techniques also provide a useful visual aid for improving soil awareness in groups of stakeholders, helping the exchange of knowledge and ideas for innovation in agriculture.
... For example, for most of the soil types in Israel, the sublayers contain more clay, and have higher salinity and sodicity and lower levels of OM than the top layers (Singer, 2007). Moreover, in most cases, the sublayers are also more compacted and dense than the top layers because of the physical stress imposed by the weight of the upper soil layer on the sublayer (Sheoran et al., 2010;Shabtai et al., 2014;Ball et al., 2015). ...
... Despite the soil samples from the top-and the sub-layers had the same mineralogy, and similar organic matter and CaCO 3 contents (Table 1), the average bulk density of the aggregates in the soils from the sublayers was significantly (p ≤ 0.05) higher (1.64 g cm − 3 ) than in the soils from the top-layer (1.48 g cm − 3 ) (Fig. 8). It is most likely, that these high bulk density values of the aggregates in the sublayer soils was a result of the higher physical stress imposed by the weight of the upper soil layers on the sublayers (Ben-Hur et al., 1998;Sheoran et al., 2010;Ball et al., 2015;Tanner et al., 2018). Consequently, the number of the physical contacts, and the cohesive forces between the particles inside ...
Article
Soils are turned over during agronomic and environmental activities, such that the sublayer becomes the topsoil. Because subsoils have been subjected to high pressures over long periods in the field, their activities and functionality can be changed when they are shifted to the top layer. The present work objective was to investigated the mechanisms and processes affecting the structural stability, and consequently saturated hydraulic conductivity (K s), of a semi-arid soils, which were taken from < 0.3 m depth (top soils) and > 0.3 m depth (sublayers soils). Disturbed soil samples, with similar aggregate-size distribution and bulk densities, were packed in columns, prewetted with saline solution (SS), and then their K s values were determined during consecutive leaching with SS and deionized water (DI). The K s values of the various soils under SS leaching differed due to slaking and swelling processes that changed the soil structure. The effect of the slaking process on K s reduction was more significant in the top-than sublayer soils. Soil swelling under SS wetting and leaching caused mainly by penetration of water molecules into capillary pores in the soil that increases the pores volumes, and enlarges the aggregate swelling (matrix-type swelling). The average bulk density, and consequently the structural strength, of the aggregates in the sublayer soils were significantly higher than that of the top soils. This suggested that, under matrix-type swelling, less aggregates would be broken in the sublayer than in the top-layer soils. During leaching of the top and the sublayer soils with DI, the aggregates breakdown and K s reduction were caused mainly by dispersion and osmotic swelling of the clay fractions in the soil. In this case, a negative relationship between the K s and SAR values was obtained, regardless of the soil depths.
... Additional studies for evaluating impacts of sugarcane management on soil structure assessed by VESS should be carried out through the whole sugarcane cycle (about five years). Furthermore, subsoil compaction in sugarcane fields should also be evaluated using the field methodology such as SubVESS, proposed by Ball et al. (2015). The SubVESS is a methodology for assessing soil structural quality below spade depth, i.e. from 25 to 200+ cm depths (Ball et al., 2015;Batey et al., 2015). ...
... Furthermore, subsoil compaction in sugarcane fields should also be evaluated using the field methodology such as SubVESS, proposed by Ball et al. (2015). The SubVESS is a methodology for assessing soil structural quality below spade depth, i.e. from 25 to 200+ cm depths (Ball et al., 2015;Batey et al., 2015). We consider subsoil compaction an important concern since sugarcane roots have the potential to explore soil layers much deeper than 25 cm. ...
Article
Increasing global demand for biofuel has accelerated land-use change (LUC) in Brazil, primarily through the planting of sugarcane (Saccharum officinarum) to replace degraded pastures. The intensive mechanization associated with this LUC has increased concerns regarding structural quality of Brazilian tropical soils. Through decades of research focusing on identifying sensitive indicators of soil degradation due to land use and management, the Visual Evaluation of Soil Structure (VESS) method has emerged as a simple, fast, reliable and accurate semi-quantitative approach for assessing soil structure changes. VESS integrates soil properties related to size, strength and porosity of aggregates, and root characteristics into a single score (Sq - structural quality) that ranges from 1 (good structural quality) to 5 (poor structural quality). Although the VESS method was developed for temperate soils, it has been used successfully as an indicator of soil and crop management practice effects on structural quality of tropical and subtropical soils. Our objectives were to evaluate soil structural quality changes associated with a LUC sequence (i.e., native vegetation to pasture to sugarcane) at three sites under Oxisols, Alfisols and Ultisols across central-southern Brazil using the VESS; and to correlate VESS scores with quantitative measurements of soil physical properties. Average VESS scores were 2.0, 2.7, and 3.1 for native vegetation, pasture, and sugarcane, respectively. Overall the VESS method was able to detect soil structural quality changes under LUC for sugarcane cultivation, indicating a decrease in soil quality from native vegetation through pasture to sugarcane. The VESS scores were significantly correlated with quantitative soil physical property measurements, suggesting VESS is a reliable indicator of soil structural quality in tropical soils. A VESS score Sq = 3.0 seems to be suitable as a guide for management decisions. We conclude that VESS scores provide an efficient method to identify impacts of sugarcane expansion on soil structural quality, and recommend that VESS assessment be incorporated into monitoring protocols for evaluating not only sugarcane expansion areas, but also overall soil quality/health in Brazil.
... Ecological Indicators 108 (2020) 105770 0-30 cm) than deeper soil (Fig. 3, 30-60 cm) reflects the focus on productive function. While agricultural operations such as ploughing are mostly done to 30 cm depth, subsoil degradation has been reported as one of the main threats for crop productivity (Ball, et al., 2015). Subsoil condition is important for the storage of soil water to support crop production, especially in semi-arid climate (Ball, et al., 2015). ...
... While agricultural operations such as ploughing are mostly done to 30 cm depth, subsoil degradation has been reported as one of the main threats for crop productivity (Ball, et al., 2015). Subsoil condition is important for the storage of soil water to support crop production, especially in semi-arid climate (Ball, et al., 2015). Subsoil quality regulates the rooting depth which is associated with the availability of soil water and nutrient for plant. ...
Article
Current management practices are thought to be having adverse impacts on soil quality for semi-arid agriculture. A multidimensional quantification of soil quality was developed and tested under irrigated and rain-fed agricultural systems in the northwest of Iran. Thirty-four chemical, biological and physical soil quality indicators were quantified at two depths with mono-cropping and crop rotation (n = 154). Discriminant analysis (DA) and principal component analysis (PCA) were applied to identify a minimum data set (MDS) for developing soil quality indices (SQI). Soil organic carbon (SOC), soluble sodium (Na), geometric mean diameter of soil aggregate (GMD) and available zinc (Zn) were identified using PCA, and GMD, Zn and soil microbial respiration (SMR) were identified using DA. Six SQIs were produced using non-linear and linear scoring equations and integration approaches based on two independent MDS. SQIs were significantly different between irrigated and dry farming at both depths (P-value < 0.05), although there was no impact of crop rotation under conventional tillage. The best index was produced using linear scoring and additive integration based the MDS selected using discriminant analysis. While the PCA is the conventional technique for reducing data redundancy, DA identified a more useful MDS than PCA. The importance of soil aggregate stability, heavy metal pollution, biological activity, organic carbon content and soil sodicity was noted for monitoring and assessing the main threats to SQ, these did not have to be directly quantified for a useful SQI, but need to be understood for interpretation. The SQI provided a rapid, reproducible and reliable method for multifaceted assessment of soil quality. The study indicated adverse impact on soil quality of management systems operating in the semi-arid regions of Iran under rain-fed farming.
... Although better soil structural quality was defined under CT system compared to NT by the VESS method, this should not mean that CT system has no detrimental impact on soil structural quality. Because, the VESS method assesses soil structural quality only up to 25 cm depth; hereby, the VESS cannot capture degradation in structural features below 25 cm depth (Ball et al., 2015) and may not suggest reliable management requirement (Emmet-Booth et al. 2019). ...
... Therefore, methods such as SubVESS (Ball et al. 2015;Ball et al. 2017) or DS (Emmet-Booth et al. 2019) considering below 25 cm depth are needed to assess the structural quality of conventionally tilled soils. Moreover, the beneficial effect of tillage as indicated by low VESS scores will prevail only for the short term due to the adverse impact of breaking aggregates on the loss of organic carbon (Cherubin et al. 2017). ...
Article
Current agricultural practices and their impacts on the sustainability of crop production can be evaluated by simple and reliable soil structure assessment tools. The study was conducted to determine the effects of long‐term (2006‐2017) tillage systems on structural quality of a clayey soil using the visual evaluation of soil structure (VESS) and classical field and laboratory measurements. A field experiment with seven tillage systems, representing both traditional and conservation tillage methods was conducted on a clayey soil in the Cukurova region, Turkey. Soil samples from 0‐10, 10‐20 and 20‐25 cm depths were analyzed for mean weight diameter (MWD), porosity and organic carbon. Penetration resistance (PR) was determined in each treatment plot. The VESS scores (<2) of upper 0‐5 cm indicated a good structural quality for all tillage systems. The VESS scores were positively related to PR and MWD and negatively to macro (MaP) and total porosity. In reduced and no‐till systems, poorer soil structures were observed in subsurface layers where firm platy and angular blocky structures were defined. Mean VESS score (3.29) in 20‐25 cm depth where PR was 3.01 MPa under no‐till indicated a deterioration of soil structural quality; thus, immediate physical interventions would be needed. Lower VESS scores and PR values under strategic tillage which was created by plowing half of no‐till plots in November 2015 indicated successful correction of compaction caused by long‐term no‐till. The results suggest that the VESS approach is sensitive and useful in distinguishing compacted layers within the topsoil.
... Subsoil compaction may also be a potentially negative impact of excessive stover harvest under CP as suggested by an average Sq value of 3.88 for the 5-to 20-cm layer. Our assessment did not examine subsoil conditions, although a visual methodology for evaluation of subsoil compaction was recently proposed by Ball et al. (2015) and may be useful for assessing the impacts of tillage systems and corn stover harvest for biofuel production. ...
Article
Full-text available
High levels of corn (Zea mays L.) stover harvest for ethanol production have raised concerns regarding negative consequences on soil structure and physical quality. Visual soil structure assessment methods have the potential to help address these concerns through simple, straightforward on-farm evaluations. Our objective was to determine if the visual evaluation of soil structure (VESS) approach could detect soil structural quality differences associated with different levels of corn stover harvest and tillage practices. We evaluated no harvest and moderate and high stover harvest levels within no-tillage (NT) and chisel plow (CP) plots following 7 yr of continuous corn. Undisturbed 10- by 20- by 25-cm soil samples were taken using a spade in April 2015. The thickness and structural quality (Sq) scores for the 0- to 5- (top) and 5- to 20-cm (bottom) soil layers were determined, and an overall Sq was computed. The Sq values showed a significant interaction between corn stover harvest and tillage practice. Soil structural quality showed no significant differences between NT and CP systems for either the no- or moderate-harvest treatments, but with a high stover harvest rate, CP structural quality was worse than NT. With NT, both moderate and high rates of stover harvest significantly increased Sq compared to no harvest; in CP, there was no significant difference between the no- and moderate-harvest treatments. Only a high level of stover harvest had an adverse effect on the Sq rating. The VESS approach was sensitive for detecting the effects of corn stover harvest and tillage systems on soil structural quality and should be further evaluated as an integrative, on-farm soil quality/health indicator. © 2016 Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
... In arid and semiarid regions, the soils are frequently characterized by increasing salinity and sodicity levels with soil depth (Bresler et al., 1982;Sarah, 2004). Moreover, the physical stress imposed by the topsoil layers in the field can increase the compaction and density of the subsoil layers (Sheoran et al., 2010;Shabtai et al., 2014;Ball et al., 2015), while this compaction can be affected by the subsoil's physical and chemical properties, such as organic matter content and soil texture, salinity and sodicity (Shabtai et al., 2014). Therefore, exposure of waste subsoils to the atmosphere may augment soil erosion which, in turn, can accelerate their negative effects on the environment. ...
Article
Excess soils from construction sites (waste soils) become a problem when exposed to soil erosion by water or wind. Understanding waste soil erodibility can contribute to its proper reuse for various surface applications. The general objective of the study was to provide a better understanding of the effects of soil properties on erodibility of waste soils excavated from various depths in a semiarid region under rainfall and wind erosive forces. Soil samples excavated from the topsoil (0-0.3m) and subsoil layers (0.3-0.9 and >1m depths) were subjected to simulated rainfall and wind. Under rainfall erosive forces, the subsoils were more erodible than the topsoil, in contrast to the results obtained under wind erosive forces. Exchangeable sodium percentage was the main factor controlling soil erodibility (Ki) under rainfall, and a significant logarithmic regression line was found between these two parameters. In addition, a significant, linear regression was found between Ki and slaking values for the studied soil samples, suggesting that the former can be predicted from the latter. Soil erodibility under wind erosion force was controlled mainly by the dry aggregate characteristics (mean weight diameter and aggregate density): their higher values in the subsoil layers resulted in lower soil erodibility compared to the topsoil.
... Several "spade tests" were proposed, such as the Peerlkamp (1959) test, the "Visual Evaluation of Soil Structure" (Ball et al., 2007;Guimarães et al., 2011), the "Visual Soil Assessment" (Shepherd, 2009(Shepherd, , 2000, or the "SOILpak score" (McKenzie, 2001). A similar approach exists for subsoil (Ball et al., 2015). In the topsoil evaluations, an undisturbed soil block is extracted from soil surface with a spade (e.g., full size of the spade and approximately 20 cm-thick) and manually broken or dropped from a 1 mheight to produce aggregates. ...
Article
Since many processes in soil are highly sensitive to soil structure, this review intends to evaluate the potential of observable soil structural attributes to be used in the assessment of soil functions. We focus on the biomass production, storage and filtering of water, storage and recycling of nutrients, carbon storage, habitat for biological activity, and physical stability and support. A selection of frequently used soil structural properties are analyzed and discussed from a methodological point of view and with respect to their relevance to soil functions. These are properties extracted from soil profile description, visual soil assessment, aggregate size and stability analysis, bulk density, mercury porosimetry, water retention curve, gas adsorption, and imaging techniques. We highlight the greater relevance of the pore network characterization as compared to the aggregate perspective. We identify porosity, macroporosity, pore distances, and pore connectivity derived from imaging techniques as being the most relevant indicators for several soil functions. Since imaging techniques are not widely accessible, we suggest using this technique to build up an open access “soil structure library” for a large range of soil types, which could form the basis to relate more easily available measures to pore structural attributes in a site-specificway (i.e., taking into account texture, soil organic matter content, etc.).
... If one is interested in the absolute soil quality at a particular site, then the average value from a VSE observation from a group of observers would produce an accurate representation (Ball et al., 2007;Klimeš, 2003). To increase agreement between observers, those observers could cross-check their findings regularly in order to become more consistent in the way of observing (Guimarães et al., 2011;Ball et al., 2015). For sites having more similar conditions it could be more difficult to detect differences in soil quality characteristics, as subjectivity errors will become more evident (Ball et al., 2007). ...
Article
Visual soil evaluation (VSE) is a simple and fast method to assess soil quality in situ, and is becoming increasingly popular. Besides soil structure assessment, also other soil properties can be assessed such as grass cover, roots and earthworms. Yet, the full set of visual observations has not been properly evaluated for reproducibility and correlation with standard field or laboratory measurements, for several soil types. The objectives of this study were therefore to evaluate the reproducibility and the correlation of visual observations with closely related field or laboratory measurements. We used quantitative visual observations where possible, to enhance objectivity of VSE. The reproducibility and correlation of visual observations with standard measurements was evaluated for three soil types (sand, peat and clay) in the North Friesian Woodlands, The Netherlands. Reproducibility of quantitative visual observations was tested by comparing observations made by farmers and soil scientists, on the same soils. A linear mixed-effect model indicated that for all quantitative visual observations except for the depth of soil compaction, subjectivity due to the observers’ background (farmer or soil scientist) had no significant effect on the observations. For assessment of relative soil quality differences between sites, the results suggested that a single observer can make the visual observations, when assessing the fraction largest soil structural elements, earthworms, gley mottles and the depth of soil compaction. Spearman’s rank correlation coefficients indicated that visual observations of grass cover, root count, maximum rooting depth and the fraction largest soil structural elements correlated significantly with closely related field or laboratory measurements regardless of soil type. Maximum rooting depth, root count, soil colour, the fraction largest soil structural elements, and the degree of soil compaction only significantly correlated with field or laboratory measurements for specific soil types. Analyses showed that the correlation of visual observations with standard measurements were soil type dependent, suggesting that the evaluation of soil quality should also be soil type dependent.
... Soil occupies a special position because of its agronomic and environmental functions in the preservation of natural resources. However, land degradation is becoming a growing problem worldwide (Ball et al. 2015). Various processes, in particular the collapse followed by erosion, contribute to this soil degradation (Abdellaoui et al. 2011). ...
Article
Full-text available
The physical properties of soils are important for proper monitoring of soil functions. In order to evaluate soil resistance to agricultural equipment, a study was carried out on the four main soil types (ferralitic, ferruginous, hydromorphic and vertisol) in the eight agroecological zones of Benin. The objective of this work was to determine the physical and mechanical parameters of the soils. A sampling of soil types by agroecological zone was carried out in 36 localities in Benin to record vertical and horizontal soil strengths using a compactometer and a penetrometer. These data were complemented by measurements of texture, density and water content of the soil samples. An analysis of variance, polynomial regressions and Pearson correlation were performed between the parameters studied. It is noted that majority of soils assessed were sandy loam. The high sand content in most soils would be due to the depth considered (20 cm). The bulk densities range from 1.21 to 1.73gcm-3 and water contents from 4.9 to 35.11%. Vertical resistances range from 3.89 to 16.36 kg cm-2 and horizontal resistances from 1.03 to 4.44 kg cm-2. Strong soil resistances (vertical and horizontal) are recorded in the northern part of Benin where large proportions of the gravels were observed in the samples taken. A positive correlation was observed between vertical resistance and horizontal soil resistance. It can be concluded that soil resistance in Benin vary from one agro-ecological zone to another, but the linking of soil properties is less significant between zones.
... The application of the VESS system provides a useful mechanism for assessing soil quality in terms of soil degradation and can be repeated at intervals over several years to give an estimate of the resilience of the soil in the landscape [3]. A subsoil version SubVESS that describes anthropogenic impacts from inspection of soil in pits is also available [9]. Training videos and information on the use of VESS and SubVESS are available at the website http://www.sruc.ac.uk/vess. ...
Chapter
The Visual Evaluation of Soil Structure (VESS) assesses the physical quality of soil and can help scientists, advisors and farmers to make decisions about soil management practices and sampling strategies. It involves detailed examination of soil structure as well as identifying layers affected by soil management. It is accessible to non-experts. The VESS method is briefly described; it is a spade method that involves aggregate exposure by breaking up sample blocks manually. In the top 0-25 cm depth, the size, shape and visible porosity of the aggregates are assessed using an illustrated scoring key applied to individual layers. A weighted average gives an overall score of soil quality (Sq). Scores can be related to different land uses within the landscape, to quantified soil physical properties, to the variability of crop yield and to soil remediation. Recommendations for application of the method to describe landscapes with different land or soil management and to improve soil structural quality for better agronomic performance are provided.
... Visual evaluation was used to make compaction diagnosis ( Batey and McKenzie, 2006) or soil quality monitoring ( Ball and Douglas, 2003). The method was recently developed and improved based on the classical spade test ( Ball et al., 2007Ball et al., , 2015Guimarães et al., 2011). It was adapted to clod size samples ( Johannes et al., 2016) and showed good relationships with physical measurements, organic carbon content ( Guimarães et al., 2013;Johannes et al., 2016;Moncada et al., 2015) or yield ( Mueller et al., 2009). ...
Article
Scoring the structure quality of the soil with the Visual Evaluation of the Soil Structure (VESS) spade test receives growing interest due to its simplicity, reliability and the quality of the evaluation provided. Sampling requirements to achieve a predefined quality of estimation, however, were not defined. This paper aims at filling this knowledge gap. The spatial variability of VESS scoring is analysed in two field, one with homogeneous micro-topography and vegetation growth and one showing spots of two distinct states with respect to these criteria. The semi-variograms showed purely random distribution of the scores from 6-10 to > 150 m of inter distances between observations, thus allowing to calculate the number of spade tests required to reach objectives of accuracy or minimum detectable difference. The two zones of the heterogeneous field, and the homogeneous field, showed the same coefficient of variation of 11%, which is small. Therefore, 5 spade tests only are enough to detect a 0.5 change of the scoring. This number is smaller than usually recommended or performed. The classical recommendation to sample in homogeneous vegetation growth is supported by our results. These results probably apply to most situations and can be used to design monitoring protocols.
... Spade methods are easy to implement, but they are mainly used to evaluate the quality of the topsoil structure. SubVESS has been developed to supplement VESS for use where compaction has occurred below topsoil depth (Ball et al., 2015). In this case, a soil pit is examined with a greater emphasis placed on the transition layer including the old plough layers and the top of the subsoil layer. ...
Article
Quick and reliable field methods are needed to assess soil structure quality. This is especially true in cropping systems with high proportions of sugar beet, potato and vegetables crops, where the risk of soil and subsoil compaction is high. Visual field methods are a priori well adapted to meeting these needs. These include spade methods and soil profile methods. Spade methods are easy to implement but are mainly used to evaluate topsoil structure quality. The “profil cultural” method allows more detailed structural assessment, particularly in depth, but it requires more training, is time consuming and strongly disturbing for the soil. The proposed method, called "mini3D soil profile", is an intermediate method between spade methods and “profil cultural”: the sampling method is similar to the spade method and the description of morphological units by mapping the structural state on a vertical face is similar to the “profil cultural” method. It consists of taking a soil block with the pallets of a telescopic loader, and assessing soil structure on the vertical face using criteria similar to those of the “profil cultural” method. A study was carried out to test whether (i) extraction and lifting of the soil block did not modify the soil structure and (ii) whether the method produces the same soil structure assessment as that produced by the “profil cultural”. Results show that, despite the extraction and lifting by the loader, the method allows a good characterization of the soil structure by mapping the morphological units on a vertical face. The two methods produced very similar results in the evaluation of soil structure. The correlation between the areas having a massive structure and no visible macropores (percentage of Δ areas) assessed with the “mini3D soil profile” and the areas assessed with the “profil cultural” method was significant (R-squared = 0.79). Similarly, the correlation of the percentage of Φ areas with the presence of cracks was also significant (R-squared = 0.81). Comparing the soil structure assessment in eight fields, the main differences are due to the spatial variability of soil structure within the plot, depending on the location of the soil profiles. In conclusion the method is well adapted to identify the effects of tillage and compaction on soil structure dynamics. Easier to implement than the “profil cultural” method, the "mini3D soil profile" method is an original method to promote the evaluation of soil structure and thus decision-making by advisers and farmers.
... The importance of aggregate structure to soil function has stimulated extensive research on the effect of soil type, climate and soil management on aggregate characteristics at different scales of observation. At the field level, there is a strong focus on qualitative assessment of size, shape and strength of aggregates in relation to soil profile classification (FAO, 1990) as well as on soil structural quality (Ball et al., 2007(Ball et al., , 2015. Qualitative field assessments, have in many cases been supplemented with or exchanged by more detailed observations on aggregate size and shape (Dexter, 1985), strength (Braunack et al., 1979) and stability (e.g. ...
Article
Soil aggregate properties, such as strength, shape and porosity, influence a range of essential soil functions and there is a need for more detailed understanding of the effect of soil management on these aggregate properties. There is also a need for improved knowledge on the link between aggregate and bulk soil properties. The objectives of this study were to quantify the long-term effect of rotation and tillage on aggregate shape, strength and pore characteristics, to evaluate the influence of aggregate shape and pore characteristics on aggregate strength and soil friability and to correlate aggregate properties to bulk soil properties. Soil core samples were taken in spring 2010 from the long-term rotation and tillage trial (initiated in 1980) at the University of Guelph, Canada. The rotations included were continuous corn (R1) and a diverse rotation (R6), and the tillage treatments were mouldboard ploughing (MP) and no-tillage (NT). The soil cores were exposed to a drop shatter test and air-dried before separation into different size fractions. Ten aggregates from the 4–9.2 mm size fraction per core sample (i.e. 320 in all) were X-ray micro-CT scanned. The size, shape and porosity of the aggregates were determined using image analysis with 40 μm voxel size. Subsequently, aggregate tensile strength was determined in an indirect tension test. Rotation had a more pronounced effect than tillage treatment on the different aggregate properties. The diverse rotation resulted in higher aggregate total porosity and more rounded aggregates than the continuous corn rotation. Surprisingly, there was no treatment effect on X-ray micro-CT resolvable porosities. Aggregate strength decreased with both total and X-ray micro-CT resolvable porosity even though the correlations were weak. Significant correlation was also found to aggregate sphericity although only around 10% of the variation in tensile strength could be explained by this property. Our study highlights that caution must be taken when trying to predict aggregate strength from general aggregate characteristics. For both bulk soil and aggregates, the R6-MP had highest and R1-NT lowest porosity. Tillage had strongest effect on bulk soil porosity, whereas aggregate total porosity was only affected by rotation. Our results suggest that the scale of observation is important when evaluating the influence of soil management. A strong correlation was found between aggregate strength and pore characteristics and soil fragmentation in a drop shatter test, i.e. 55% of the variation could be explained. Our study indicates therefore that bulk soil fragmentation behaviour can be predicted from aggregate characteristics. It needs to be highlighted that our results are based on one long-term experiment on a silt loam soil. The results need to be verified for soils with different soil types, climates and management histories.
... Some give scores to individual attributes and then calculate arithmetic mean values (e.g. coreVESS; Johannes et al., 2017), use weighting factors assigned to each attribute (Visual Soil Assessment, VSA; Shepherd, 2009) or take the most frequent score given to individual attributes (subVESS; Ball et al., 2015). Others designate an integrated score based on the different (non-scored) individual attributes presented in tabular format (e.g., VESS; Guimarães et al., 2011) or by using a flowchart like in one of the most recent variants, grassVESS (Emmet-Booth et al., 2018). ...
... The overall Ssq for each subsoil layer was produced based on the most frequently occurring quality structure scores of the five diagnostic factors stated above to establish the presence or absence of subsoil compaction characteristics. An overall score of Ssq 1 indicates a very good quality, Ssq 2-4 shows intermediate soil quality, and Ssq 5 indicates a very poor quality (Ball et al., 2015b). ...
Article
Subsoil compaction is one of the major causes of land degradation worldwide and therefore a major threat to future crop productivity. The objective of this contribution was to evaluate the effects of compaction treatments on soil structure based on the numerical visual evaluation of subsoil structure (SubVESS) method and on quantitative measurements of soil pore characteristics. The effect of soil compaction was evaluated using treatments from a compaction experiment initiated in 2010 at Research Centre Flakkebjerg, Denmark, on a sandy loam soil using five levels of compaction. In this study we used i) non-compacted reference, ii) Treatment M3, where soil was subjected to multiple passes (five wheel passes per compaction event annually) of a tractor-trailer combination with max. wheel load of ∼3 Mg, and iii) M8, with multiple passes (four wheel passes per compaction event annually) of a tractor-trailer combination with max. wheel load of ∼8 Mg. The tire inflation pressure was generally above the recommended pressure in order to mimic the inflation pressures commonly used in practice. The treatments were applied track-by-track in the spring of 2010–2013 when the soil water content was close to field capacity. Spring barley (Hordeum vulgare L.) was established every year after a shallow secondary tillage to ∼0.05 m depth to loosen the uppermost layer. Sampling and field evaluation were done on May 7, 2014, i.e. after four years of compaction treatments (2010–2013) and one year of recovery. The soil profiles were evaluated at the same time as soil cores were sampled at 0.3, 0.5 and 0.7 m depth. In the laboratory, we measured water content, total porosity, air-filled porosity (εa), air permeability (ka) and calculated pore organization indices (PO1 = ka/εa and PO2 = ka/εa2) on the soil cores. We estimated the blocked air-filled porosity and pore continuity index from the relationship between air permeability and air-filled porosity for −30 to −300 hPa matric potentials. Assessment using the SubVESS method showed a marked effect of the M8 treatment on soil structural quality down to ∼0.65 m depth, but the effects of the M3 were not significantly different from the control at any depth. This was confirmed by the laboratory-measured data, which showed that the M8 treatment drastically reduced total porosity, air-filled porosity, air permeability, pore size distribution, pore tortuosity and continuity, especially at 0.3 and 0.5 m depths. Detailed measurements of the anisotropy of soil pore characteristics at 0.3–0.4 m depth showed that for PO2 (pore size distribution) and blocked air-filled porosity the control soil was significantly anisotropic. Although compaction with the ∼8 Mg wheel load affected the vertically and horizontally-oriented pores differently, it did not significantly affect the anisotropy of the different pore characteristics. Our results showed that in general, there was a good agreement between the field and laboratory methods and thus, the two can be combined to evaluate the effects of compaction in the subsoil.
... Plusieurs tests ont été proposés, tels que le test de Peerlkamp (1959), l'« évaluation visuelle de la structure du sol » (Ball et al., 2007;Guimarães et al., 2011), l'« évaluation visuelle du sol » (Shepherd, 2000;Shepherd, 2009), ou le score « SOILpak » (McKenzie, 2001). Une approche similaire existe pour le sous-sol (Ball et al., 2015). Une "bonne" structure du sol, selon les méthodes de l'évaluation visuelle, a souvent été associée à une faible densité apparente du sol, une faible résistance à la pénétration, une faible résistance à la traction, un faible compaction Rabot et al., 2018). ...
Thesis
La complexité remarquable du sol et son importance pour un large panel de services écosystémiques présentent des défis majeurs pour évaluer les processus pédologiques. En dépit des progrès importants accomplis au cours des cinquante dernières années dans la caractérisation des propriétés hydriques, les méthodes analytiques demeurent coûteuses et chronophages. La spectroscopie proche infrarouge (SPIR) a été largement utilisée comme technique rapide, non destructive et peu coûteuse pour prédire différentes propriétés du sol y compris la teneur en eau. Toutefois, moins d’attention a été accordée à l’évaluation des propriétés hydriques et leurs variations en fonction des propriétés physiques du sol. L’objectif principal de ce travail est d’analyser la validité et la pertinence de la SPIR dans l’évaluation des propriétés hydriques et leur relation avec les caractéristiques du sol.Dans cette étude nous nous sommes focalisés sur la largeur à mi-hauteur de la bande d’absorption proche de 1920 nm pour identifier un nouvel indice spectral, noté SWSI pour caractériser l’état hydrique du sol. Nos résultats montrent une relation linéaire entre SWSI et la teneur en eau du sol (R2 >0.9). Ils ont monté aussi que SWSI est pertinent pour étudier les effets de la texture, de la teneur en carbone organique et des pratiques agricoles sur les propriétés de rétention en eau du sol. En outre, en utilisant les paramètres de cette relation linéaire, nous proposons une nouvelle approche pour caractériser les propriétés hydriques et la qualité physique des sols. En comparaison avec des méthodes clas
... As this work focused on studying soil quality in the topsoil (up to 25 cm), future investigations about deeper layers would be important to infer about soil quality in the entire soil profile, including the subsoil. Although the on-farm methods of soil quality assessment tested in this work were spade tests proposed to assess soil quality in the topsoil, existing methodologies could be used to assess soil quality further in the soil profile ( Ball et al., 2015;Tavares Filho et al., 1999) or maybe the DRES and PGPE methods tested could be developed to include subsoil assessments. ...
... We assumed that the soil was well watered and that penetrometer resistance was determined by depth and density, which is the most optimistic scenario with respect to root penetration into strong soil, because drier soils will have a greater penetrometer resistance ( Figure 2). Our predictions show that the most widely reported phenomenon of a compacted layer would indeed affect rooting depth, as is commonly reported (Ball et al. 2015), but even if compaction were completely ameliorated rooting depth would still be restricted. These predictions ignore soil drying, but they do provide realistic descriptions of soil strength profiles of winter wheat in UK conditions. ...
Article
We argue that the well-known effects of increasing pressure with depth due to the weight of soil (called surcharge) makes the soil so strong that roots can elongate to deeper layers only if they can locate existing pore networks. At depths as shallow as 50 cm, increases in soil strength, even in well-watered soil, are so great that root elongation by the process of soil deformation is only likely to occur at very small rates (less than approximately 1 mm/day). An over-reliance on pot-based laboratory experiments to investigate the impacts of soil strength on root penetration, both in plant and soil science, has meant that increases in soil strength simply due to the axial pressure of soil has been overlooked. In this article we outline the implications of this oversight and propose root traits that might confer deep rooting. The importance of the root's ability to deform hard layers is re-evaluated and we suggest that it should still be viewed as an important trait, but not closely associated with deep rooting. This article is protected by copyright. All rights reserved.
... Soil structure conditions govern plant root development because they affect the air, water and nutrient distribution in the soil matrix, and determine the force the roots might need to penetrate and propagate downward (Bengough et al., 2006). Under conventional tillage with heavy traffic, the subsoil is commonly characterised by compacted layers with a massive structure (Ball et al., 2015). ...
Article
The least limiting water range (LLWR), has been used as a soil structural quality indicator for identifying in-season water dynamics, yet studies focusing on its use for detecting in-season water stresses and their effect on crop response on severely compacted subsoils are scarce. The objectives of this study were, therefore, to examine the in-season water dynamics on a tile-drained soil with compacted subsoil in the light of two different approaches for calculating LLWR (standard LLWR by da Silva et al., 1994; and refined LLWR by Pulido-Moncada and Munkholm, 2019), and to evaluate the crop response to aboveground and belowground conditions. Information on LLWR´s was obtained from soil sampling in the most contrasting treatments of a compaction experiment: with and without compaction. In-season water dynamics were measured from 2017 to 2019. The refined LLWR approach defined a wider range of water content non-limiting for plant growth, as compared to the da Silva et al. approach. Compaction affected the LLWR’s (p < 0.05), yet no significant effect of subsoil compaction on crop yield was found. Cumulative aeration and water stress day indicators identified from the refined LLWR were significantly related to grain yield (p < 0.05). The lower winter wheat yield in 2018 as compared to 2019 seemed to be related to the direct impact of weather factors on aboveground growth, and aeration and water stresses. The apparent lack of compaction effect suggests further studies are needed to determine if in-season stresses derived from the LLWR’s can be related to crop development and yield under different soil and weather conditions.
... In the research context, the most used spade methods are the VSA (Visual Soil Assessment) [92] and the VESS (Visual Evaluation of Soil Structure) developed from the Peerlkamp method [90,93]. Among the soil profile methods, 'Profil Cultural' [94,95], SOILpak [96] and, most recently, the numeric visual evaluation of subsoil structure methods (SubVESS) [97] are used. Details of the methods have been published in a systematic review [98]. ...
Article
Full-text available
The diffusion of tree crops has continuously increased during the last decades all over the world. The market boost has favored the adoption of intensive and highly mechanized cultivation, often triggering the degradation of the soil physical-hydrological qualities, mainly through enhanced soil erosion and compaction. Several papers have been published on soil degradation and restoration strategies in specific perennial crops and environments. This review paper collects such studies showing the sensitivity of soil under tree crops to the degradation of their physical-hydrological qualities. Then it reports the state of the art on the methodologies used for the evaluation of the physical-hydrological qualities in the field and in the laboratory, also suggesting an improved methodology for estimating the actual available water capacity. Some updated and promising experiences to recover the physical-hydrological qualities of soil are then illustrated. In particular, subsoiling and placement of drainages, spreading of organic amendments, compost, biochar, using of cover crops, and biological inoculants. A key point in applying the restoration practices is that they should not only be specific for the soil and tree rooting system, but also tailored according to the ecosystem functions that need to be improved besides plant health and yield.
... Soil structural assessments can be used by growers to assess how their management practices are impacting soil quality (Vieweger, 2016) to allow for the early detection of developing compaction problems (Askari et al., 2013). Despite concerns of subjectivity (Mueller et al., 2009;Askari et al., 2013), Visual Soil Evaluation (VSE) methods can reliably provide a semi-quantitative in-field soil structural assessment (Askari et al., 2013;Ball et al., 2015;Emmet-Booth et al., 2018;Murphy et al., 2013). A rating score, based on visual indicators of macro-morphological soil characteristics is assigned . ...
Article
Machinery traffic imposes a negative effect on soil structure, leading to soil compaction. Studies to date have primarily focused on the influence of applied wheel loads on soil structure. Few studies have assessed the impact of commercial farm operations on soil structure and crop performance, particularly on field headlands in a temperate maritime climate such as Ireland. A survey was conducted on 41 conventionally managed field sites to investigate the effect of field position (field edge, turning, transition and in-field zones) in relation to machinery operations on soil structure. Soil texture classes ranged from sandy loam to clay loam. All sites used plough-based crop establishment. Soil structural condition was assessed visually using the visual evaluation of soil structure method (VESS) for the topsoil (0−250 mm), and Double Spade below plough depth (250−400 mm). Quantitative soil measurements such as shear strength, bulk density and porosity using soil cores post-harvest, and soil cone penetration resistance were taken at two time points in the crop growth cycle. For most measurements of soil structure, the in-field zone of least machinery traffic produced the best scores (Sq 2.81 & DS 2.48), and the turning zone returned the poorest scores in the 0−250 mm soil layer (Sq 3.31 & DS 2.91). The strongest quantitative scores for the in-field and turning zones, respectively, were for trowel penetration resistance in the upper (2.49 & 3.20) and lower (3.41 & 4.05) soil depth layers and for shear vane (38.17 & 53.59 kPa) for the same zones. The visual assessments and some of the quantitative measurements (0−250 mm soil layer) followed the zone order trend of: turning, field edge, transition and in-field, for increasing machinery traffic. The results show that the visual soil indicators used in this study are more sensitive than quantitative soil measurements such as soil bulk density (ρb) or porosity (TP and MP) at detecting soil structural differences between zones, particularly below plough depth (>250 mm soil depth).
... In this study, visual evaluation of the soil structure (VESS) was carried out using the spade diagnosis method (Beste 1999(Beste , 2003Ball et al. 2007;Guimarães et al. 2011). In the last two decades, important basic work to develop a standardisable visual assessment of soil structure with spade diagnosis has been undertaken (Beste 1999(Beste , 2003Ball et al. 2007Ball et al. , 2013Ball et al. , 2015Ball et al. , 2017Shepherd et al. 2008;Guimarães et al. 2011Guimarães et al. , 2017Giannattasio et al. 2013;Sonneveld et al. 2014;Van Leeuwen et al. 2018;Emmet-Booth et al. 2019;Valani et al. 2020). As VESS is a qualitative or a semiquantitative method, assessment of aggregate stability by wet sieving was also performed as an additional test (Yoder 1936;Karamia et al. 2012;Deviren Saygına et al. 2012;Besalatpour et al. 2013;Lourdes et al. 2016) and the mean weight diameter (MWD) stability index was calculated according to Angers et al (2006). ...
Article
An on-vineyard approach was used to investigate effects of the biodynamic preparations horn manure and horn silica (BD) on the soil structure in five vineyards on different bedrocks and that had been under organic management for different time periods. The underlying hypothesis was that the effects of the biodynamic preparations increase aggregate stability and improve soil structure. The results showed that soil aggregate stability during wet sieving was not different in the treatment with biodynamic preparations (BD+), compared with that without preparations (BD-). Based on visual evaluation (VESS), improvements in soil structure in the BD+ treatment, compared with BD-, were not significant for macropores/biopores, drop test topsoil or subsoil colour, but significant improvements were observed in drop test subsoil (p = 0.009), topsoil colour (p < 0.000), root penetration (p = 0. 017), structure of surface (stable aggregates, little encrustation, p = 0.006), structure of topsoil (p = 0.030), structure of subsoil (p < 0.000) and the colour change from topsoil to subsoil was at a greater depth (p = 0.049). Based on previously reported results showing significant changes in the microbial activity in soil from the BD+ treatment, using the same soil samples, it was thought possible that the observed differences in soil structure between BD+ and BD- were linked to the differences in the microbial activity.
... Overall, the VESS and SubVESS methods enable semi-quantitative information and good judgement of appropriate, good, moderate or poor states of soil structure for extension and monitoring (Shepherd, 2000;Ball and Douglas, 2003;Ball et al., 2007;McKenzie, 2001). Several authors have shown correlations between VESS and SubVESS with other soil physical measurements, indicating that these methods can reveal differences between land use types and management options (Batey et al., 2015). Building on recent work by Ball et al. (2017), using other available Scottish agricultural soil datasets compiled from SRUC and JHI field assessments, VESS scores were found to be related to a range of relevant soil physical and water retention/flow properties, as summarised in Table 26. ...
Technical Report
Full-text available
Pathways of diffuse phosphorus and nitrogen pollution from agriculture to the water environment is complex and, sometimes, poorly understood. This report provides a review of the current state of knowledge of several plausible pathways: i) surface runoff and soil erosion, exacerbated by soil compaction and structural degradation ii) role of tramlines, iii) leaching through drain-flow and iv) hotspots that contribute greater than average pollutant loads due to the combined effect of land management intensity and soil properties. Focussing on Scotland we reviewed the relevant evidence for each of these pathways, their scale and extent, preventative measures and solutions to minimise pollutant losses, the costs and impacts on water quality associated with these preventative measures and solutions, as well as identifying key knowledge gaps and providing recommendations for future research.
Chapter
This book with nine chapters describes the main methods for visual soil evaluation (VSE) of soil structure and soil-related properties. It includes clear visual images of the variation of soil quality and how these relate to soil productivity and environmental sustainability. Such images raise awareness and provide a measure of the soil degradation that is a looming threat to the viability of world agriculture. Emphasis is given to recognizing, protecting and restoring soil quality as these are of vital importance for tackling problems of food insecurity, global change and environmental degradation. The book shows how these aims can be achieved with VSE by describing tools that can readily be used by land users and environmental authorities to assess crop performance, soil improvement and soil productivity. VSE is also placed in the context of future sustainable intensification of agriculture including factors of soil loss, resilience, climate change, scarcity of water and other resources, nutrient retention and increased risk of degradation. This book is relevant not only to students, lecturers, scientists and advisors working directly with soils but also to policy makers, food security experts, environmentalists and engineers who have an interest in soils and sustainable agricultural production. Last, but not least, it is hoped that these simple VSE techniques will be used extensively in years to come as a tool to link soil specialists and non-specialists together with the mutual aim of developing sustainable soil management to advance global food security and improve the environment.
Article
Subsoil degradation in agriculture is an increasing problem worldwide, particularly due to compaction caused by heavy machinery. Here, we describe a numeric assessment of subsoil structural quality in relation to soil as a crop growth medium and illustrate its utility with results from compaction experiments and from fields under minimum tillage. The scoring scheme resembles the topsoil visual evaluation of soil structure (VESS) (Guimarães et al., 2011) with more emphasis on examination of the profile wall and of soil fragments. The focus is on identification and evaluation of the anthropic ‘transition layer’ immediately below the topsoil, usually >30 cm depth. Layers of contrasting hardness and colour were identified and the overall subsoil quality of each layer was scored from separate, sequential assessments of soil mottling, soil strength, visible soil porosity, the pattern and depth of root penetration and aggregate size and shape using a colour diagnostic flowchart. Use of the method enabled identification of extent and severity of compact transition layers in both well-drained and imperfectly drained soils. Porosity and strength assessments were particularly relevant. Reference soils under forest or long-term grassland helped to distinguish whether subsoil structural quality resulted from the natural soil composition or from degradation by land management. The derived scores may be used to judge the requirement for amelioration by subsoil loosening by mechanical inputs (e.g. deep tillage) and/or natural processes (e.g. shrinkage crack formation). The method was also used to identify differences in subsoil structural quality within fields associated with field traffic levels (Oxisol in Brazil) and with moisture status (Luvisol in France). The focus of SubVESS on structure rather than on texture may not permit recognition of effects such as low water holding capacity that influence agronomic potential. In such cases the more comprehensive evaluation of overall agronomic potential by methods such as the ‘profil cultural’ is required.
Article
Subsoil management needs to be integrated into the current tillage regimes in order to access additional resources of water and nutrients and sustain crop production. However, arable subsoil is often deficient in nutrients and carbon, and it is compacted, affecting root growth and yield. In this study, crop yield and soil responses to loosening of the upper subsoil, without and with straw injection below the plough layer (25–34 cm), were studied during three crop cycles (2016–2018) in a field experiment near Uppsala, Sweden. Responses to straw injection after loosening were studied after single and triple consecutive applications of 24–30 Mg ha⁻¹ during 2015–2017 to spring-sown barley and oats. Subsoil loosening combined with one-time or repeated straw addition (LS treatments) significantly reduced soil bulk density (BD) and increased porosity, soil organic carbon (SOC) and total nitrogen (N) compared with loosening (L) alone (one-time or repeated annually) and the control. In treatment L, the soil re-compacted over time to a similar level as in the control. Field inspections indicated higher abundance of earthworms and biopores in and close to straw incorporation strips. Aggregates readily crumbled/fragmented by hand and casts (fine crumbs) were frequently observed in earthworm burrows. The treatment LS improved soil properties (SOC and porosity) and water holding capacity, but had no significant influence on crop yield compared with the control. Crop yield in all treatments was 6.5–6.8 Mg ha⁻¹ in 2017 and 3.8–4.0 Mg ha⁻¹ in 2018, and differences were non-significant. Absence of yield effect due to treatments could be possibly due to other confounding factors buffering expression of treatment effects on yield. Lower relative chlorophyll content in leaves in the loosening with straw treatment during early growth stages, did not affect final crop yield. Subsoil loosening performed three times gave no further improvement in soil properties and grain yield compared with one-time loosening. There was no difference in yield between repeated subsoil loosening + straw and one-time treatment. It will be interesting to study the long-term effects of deep straw injection and evaluate its impact under other soil and weather conditions.
Article
The Visual Evaluation of Soil Structure (VESS) method has been used frequently to evaluate the structural quality of soils from various parts of the planet, under different edaphoclimatic conditions and cultivation practices. In this context, this paper hypothesised that VESS is sensitive enough to detect differences between structural quality (Sq) scores of VESS from soils with different textural classes, submitted to distinct management and cultivation practices, under contrasting climates. To test this hypothesis, a systematic review and meta-analysis of global scope were conducted, with the objective of compiling and analysing all indexed scientific papers that utilised the method. Exclusion criteria were adopted with the intention of eliminating papers that did not meet the selection criteria for the meta-analysis, however, these papers were used in the systematic review. A sensitivity analysis was performed prior to the meta-analysis in order to evaluate the heterogeneity in the data set, thus increasing the scientific validity of the overall analysis. The results obtained through the systematic review showed that the number of studies using VESS has grown in recent years, not only in temperate regions, but also under diverse soil conditions and cropping systems in subtropical and tropical regions. The meta-analysis showed that temperate soils presented lower Sq scores compared to those observed in tropical and subtropical soils, whereas higher Sq scores were observed in clayey/silty soils compared to sandy soils, regardless of climate zone. Our findings also revealed that Sq scores differences induced by soil management and cropping systems were not detected by the meta-analysis. Thus, the VESS is an on-farm, practical and reliable tool for evaluating the structural quality of soils globally.
Article
The Visual Evaluation of Soil Structure (VESS) is a straightforward and practical method for characterising and scoring soil structural and physical quality, ideally suited to evaluate and monitor soil degradation in remote and undeveloped areas. The research presented here tested for the first time the feasibility of using VESS in the Amazon basin, under the specific land uses and soils (Oxisol and “Terra Preta de Índio”) of the region, and its relation with quantitative soil properties commonly used as indicators of soil physical quality. The evaluated areas, which had never been subjected to mechanisation, chemical fertilisation nor tillage, were “Terra Preta de Índio”/Anthropogenic Dark Earth; Regenerating Forest; Slash and Burn; Pasture; and Pristine Forest. The results showed that the quantitative properties were less sensitive at revealing signs of degradation than VESS and that VESS brought to light evidence of historic land use change and limitations to crop productivity. VESS was significantly correlated with soil resistance to penetration. However, VESS had difficulty capturing surface sealing, but the hands on approach to VESS allowed the user to identify these problems, despite not being listed in the reference chart. Overall, VESS was a more integrated soil quality indicator, providing more information about different soil functions than the quantitative properties, it was also a more practical method to perform making it ideal for tracking soil degradation and structural quality in similarly challenging situations. However, more research is required to fully enable VESS to capture structural quality in ‘sandified’ soils, caused by the slash and burn method widely used in the Amazon region.
Article
As the use of visual soil evaluation (VSE) methods has spread globally, they have been exposed to different climatic and pedological scenarios, resulting in the need to elucidate limitations, encourage refinements and open up new avenues of research. The main objective of this paper is to outline the potential of VSE methods to develop novel soil structure research and how this potential could be developed and integrated within existing research. We provide a brief overview of VSE methods in order to summarize the soil information that is obtained by VSE. More detailed VSE methods could be developed to provide spatial information for soil process models, e.g. compaction models. VSE could be combined with sensing techniques at the field or landscape scale for better management of fields in the context of precision farming. Further work should be done to integrate plant vigour, roots and soil fauna into VSE methods to provide general indicators of soil quality and for estimation of environmental risk factors related to soil C storage, GHG emissions and nutrient leaching, with particular reference to temporal changes. There is a great potential in combining (rather than comparing) VSE with measurements of soil structure, i.e. integrating VSE in soil structure and compaction research, as these methods provide spatial information that is difficult to obtain with other methods.
Chapter
Full-text available
Hyperspectral imaging (HSI) technique in the wavelength of 400−1000 nm was applied for the rapid and non-destructive measurement of external defects of potatoes. The hyperspectral images of seven potato types were obtained. Then the reflectance spectra of the interested areas of potato in these hyperspectral images were extracted and analysed. Five feature wavelengths (478, 670, 723, 819 and 973 nm) were selected based on principal component analysis. Principal component analysis was conducted again based on the five selected characteristic wavelengths. Potato external defects were identified through image processing methods, such as threshold segmentation, corrosion, expansion and connectivity analysis. The correct recognition rate of all the seven potato types using principal component analysis method of the characteristic wavelengths achieved 82.50%. The results showed that hyperspectral imaging technique was suitable for rapid and non-destructive assessment of external defects of potatoes.
Article
Although soil quality assessments are mostly based on analytical approaches, on-farm evaluations help farmers, advisors and researchers to analyse soils rapidly and inexpensively. This study’s hypothesis was that two on-farm soil quality assessments, the Rapid Diagnosis of Soil Structure (DRES) and the Practical Guide for Participative Evaluation of Soil Quality (PGPE) are able to distinguish the quality of soils under different management systems as effectively as the widely-used and analytical strategy SMAF (Soil Management Assessment Framework). Thus, this study aimed to test DRES, PGPE and SMAF in soils under different management systems, as well as to determine the correlation between the results from each on-farm assessment (DRES and PGPE) and SMAF results. Cambisols of conventional farming, no-tillage farming, organic farming, agroforestry systems and native vegetations were sampled in the 0−25 cm layer in two different municipalities with subtropical climate in southern Brazil. SMAF assessment was performed by integrating six soil quality indicators (total organic carbon, microbial biomass carbon, macroaggregate stability, bulk density, soil pH and available soil P) into a final soil quality index. DRES assessment combined on-farm information about soil aggregates, compaction, rupture resistance, root system and biological activity into a final soil quality index. PGPE assessment integrated the on-farm observation of organic matter, root system, soil structure, soil compaction and infiltration, erosion, water retention, soil macrofauna and soil cover into a final soil quality index. The on-farm strategies to assess soil quality DRES and PGPE were proven to be able to distinguish different soil management systems, as well as was the analytical method SMAF. The PGPE distinguished a wider range of sites than DRES, regardless the municipality or soil texture. The PGPE was more correlated with the SMAF than the DRES, especially in clayey and clayey loam soils. These results highlight the value of on-farm soil quality assessments, providing timely results for ease of interpretation.
Article
The intensification of agricultural practices to increase food and feed outputs is a pressing challenge causing deterioration of soil quality and soil functions. Such challenge demands provision of empirical evidence to provide context-sensitive guidance on agricultural management practices (AMPs) that may enhance soil quality. The objectives of this study are: (i) identify the most promising AMPs (and their combinations) applied by farmers with the most positive effects on soil quality and (ii) evaluate the sensitivity of the soil quality indicators to the applied AMPs. The impact of selected AMPs on soil quality was assessed using a Visual Soil Assessment (VSA) tool in a total of 138 pairs of plots spread across 14 study site areas in Europe and China covering representative pedo-climatic zones. The inventory and scoring of soil quality was conducted together with landowners. Results show that 104 pairs show a positive impact of AMPs on soil quality. Higher impact of the AMPs was observed in lower fertile soils (i.e. Podzols and Calcisols) as opposed to higher fertile soils (i.e. Luvisols and Fluvisols). For the single use applications, the AMPs with positive impacts were crop rotation, manuring & composting and no-tillage, followed by organic agriculture and residue maintenance. Cluster analysis showed that the most promising combinations of AMPs having a positive impact on soil quality are composed of crop rotation, mulching and min-till. The agreement between scientific skills and empirical knowledge in the field identified by the farmers confirm our findings and ensures their applicability. Core ideas: Impact of agricultural management practices on soil quality was assessed. Selected AMPs have high positive effects on soil quality in low fertile soils. Selection of visual soil indicators was confirmed by the farmers' knowledge.
Article
The intensification of agricultural practices to increase food and feed outputs is a pressing challenge causing deterioration of soil quality and soil functions. Such challenge demands provision of empirical evidence to provide context-sensitive guidance on agricultural management practices (AMPs) that may enhance soil quality. The objectives of this study are: (i) identify the most promising AMPs (and their combinations) applied by farmers with the most positive effects on soil quality and (ii) evaluate the sensitivity of the soil quality indicators to the applied AMPs. The impact of selected AMPs on soil quality was assessed using a Visual Soil Assessment (VSA) tool in a total of 138 pairs of plots spread across 14 study site areas in Europe and China covering representative pedo-climatic zones. The inventory and scoring of soil quality was conducted together with landowners. Results show that 104 pairs show a positive impact of AMPs on soil quality. Higher impact of the AMPs was observed in lower fertile soils (i.e. Podzols and Calcisols) as opposed to higher fertile soils (i.e. Luvisols and Fluvisols). For the single use applications, the AMPs with positive impacts were crop rotation, manuring & composting and no-tillage, followed by organic agriculture and residue maintenance. Cluster analysis showed that the most promising combinations of AMPs having a positive impact on soil quality are composed of crop rotation, mulching and min-till. The agreement between scientific skills and empirical knowledge in the field identified by the farmers confirm our findings and ensures their applicability.
Thesis
Dans le contexte actuel de changements globaux, faire face au défi multiple et interconnecté de la sécurité alimentaire et des impacts environnementaux s’avère fondamental pour la durabilité des systèmes agricoles. La thèse s’attache ainsi à évaluer les performances agronomiques et environnementales des systèmes en AB, en couplant un suivi expérimental réalisé sur un réseau de 35 parcelles agricoles dans la région Hauts-de-France, avec la modélisation du continuum sol-plante-atmosphère afin de mieux comprendre les processus expliquant les dynamiques de l’eau et de l’azote dans ces systèmes, en vue de promouvoir des pratiques de gestion durables.Dans un premier temps, le drainage d’eau et la lixiviation d’azote ont été quantifiés en couplant les données sol-culture-climat et le modèle LIXIM. L’analyse de la lixiviation des parcelles agricoles a permis de déterminer que les facteurs qui expliquent la variabilité. Outre le fort effet sol et l’importance des conditions climatiques sur le drainage, ils sont principalement liés à la combinaison de précédent cultural et de gestion de la couverture du sol en automne. Ces deux derniers jouent en effet sur la quantité d’azote minéral présent avant la période de drainage et expliquent la position du nitrate dans le profil de sol. Nos résultats ont montré le rôle dichotomique des légumineuses dans les systèmes de grandes cultures en AB, et la faible performance des cultures intermédiaires car semées tardivement en automne dans ce contexte.Dans un second temps, le diagnostic des déterminants de l’écart au rendement des cultures ou yield gap a été réalisé via une approche par modélisation déterministe. Le modèle sol-culture STICS a servi à estimer les différents niveaux de rendement potentiel et décomposer le yield gap, en s’appuyant sur le cas du blé tendre et du triticale. Les résultats montrent que le stress en azote permet d’expliquer la majeure partie du yield gap survenant en AB, et dans une moindre mesure les facteurs liés à la pression biotique, pour des systèmes recourant à peu ou pas d’apport azoté exogène.Finalement, le défi de la fourniture en azote dans les systèmes de grandes cultures en AB a été abordé afin de contribuer à une meilleure efficience d’utilisation de l’azote et une amélioration de la productivité des parcelles. Le modèle STICS a permis de simuler l’impact de pratiques de gestion alternatives de l’azote, par expérimentation numérique menée dans le cadre d’une approche participative, mobilisant les agriculteurs, les conseillers techniques et les chercheurs. Les résultats indiquent l’importance de la succession et des pratiques culturales, en particulier la mise en place de cultures intermédiaires et la gestion du retournement des luzernières. L’optimisation des pratiques des agriculteurs restent ainsi possible, en réduisant les émissions potentielles d’azote par lixiviation ou par pertes gazeuses, sans léser la fourniture en N pour les cultures.Dans les contextes pédo-technico-climatiques étudiés, les systèmes de grandes cultures en AB peuvent ainsi combiner performance agronomique et faibles impacts environnementaux, lorsque la gestion de l’azote est bien maîtrisée.
Article
Soil is a living heterogeneous body mass consists of solid, water, gases, organic, inorganic matters and organisms and acts upon as a source and sink of any contaminant. Nanotechnology is a diversified, dynamic and transformative technology, which stimulates the scientific innovation for the betterment of different sectors of the society which produces large number of nanocontaminants. Nanocontaminants in the soil are a major concern because of their toxicities with subsequent threat to soil, environment and human community. These contaminants may badly influence soil ecology, crop production, or product quality, ground water purity and human health. Moreover, the safety protocol for the specific nanocontaminants is yet to be developed to protect our environment and ecology. Of late many research experiments were conducted to investigate and comprehend the outcome, lethal dose and behaviour of nanocontaminants and consequently to extend this knowledge for development of bio-safety protocol to handle the nanocontaminants in the coming decade. Research initiatives are focused on to understand the impacts of manufactured nanoparticles on human being, soil and formulate combat mechanisms to mitigate the adverse consequences of nanocontaminants on human health and soil quality. While this attempt signifies an exclusive chance for soil scientists to investigate these highly potential technologies, it also emphasizes on foremost challenges to a field of research that has great scope to predict the consequences of nanocontaminants on the soil ecology and animal health. Currently nanocontaminants draw the major world research attention and need more endeavours to entirely assess their impacts. This review documented an outline of impacts of nanocontaminants in soil, which highlights the understanding of major interactive effects of nanocontaminants on soil organisms, plants, and human. This article also provides highlights of the challenges that soil researchers and policy makers face when developing risk assessment tool for nanocontaminants in soil and subsequently for human being.Graphic abstract
Book
Full-text available
The Twentieth Annual Research Review describes the ongoing research programme in the School of Biosystems Engineering at University College Dublin from over 79 researchers (10 academic staff, 2 technicians, 8 postdoctoral researchers and 59 postgraduates). The research programme covers three focal areas: Food and Process Engineering; Bioresource Systems; and Bioenvironmental Engineering. Each area is divided into sub-areas as outlined in the Table of Contents which also includes the name of the research scholar (in bold); the research supervisor(s); the title of the research; the nature* of the research programme; and the research sponsors. It also includes the noting of four awards for presentational excellence at the Twentieth Annual Biosystems Engineering Research Seminar held in University College Dublin on Thursday 12th March 2015. DOWNLOAD BOOK AT http://researchrepository.ucd.ie/handle/10197/6758
Article
Full-text available
Since the 1970s a network of underground pipes, up to 1200 mm diameter, has been installed in the UK to transmit crude oil to refineries and gas from onshore terminals for distribution. Chosen routes are subject to significant constraints. Current techniques for pipe installation involve topsoil removal and storage. Trench depth is set to allow a cover of 1200 mm overburden after pipes have been installed. The heavy machinery involved results in severe compaction of exposed subsoil. Subsoil is loosened comprehensively and topsoil replaced. Existing field drains are reconnected, and, if necessary, new drains with gravel backfill installed. Pipe installation usually takes place between April and October. Preventative measures to limit compaction during installation are not a practical option. If subsequent arable crops or grass are poorer or drainage more defective than before disturbance, the loss is assessed and compensation paid. To determine the cause of the loss >60, investigations have been made throughout the UK. Soil physical properties were assessed in an open trench using visual and tactile methods. Consistently, severe compaction in the subsoil was identified as the cause of poor crop growth or drainage; it was not observed in the topsoil. Specific recommendations for remedial action were made based on location, depth and severity of the compaction. These included the installation of additional land drains, increasing the amount of gravel above the drains, or further subsoil loosening orientated to cross gravel backfill. After appropriate remedial action, net compensation for crop losses was frequently small or negligible.
Article
Full-text available
This paper provides information about a novel approach of rating agricultural soil quality (SQ) and crop yield potentials consistently over a range of spatial scales. The Muencheberg Soil Quality Rating is an indicator-based straightforward overall assessment method of agricultural SQ. It is a framework covering aspects of soil texture, structure, topography and climate which is based on 8 basic indicators and more than 12 hazard indicators. Ratings are performed by visual methods of soil evaluation. A field manual is then used to provide ratings from tables based on indicator thresholds. Finally, overall rating scores are given, ranging from 0 (worst) to 100 (best) to characterise crop yield potentials. The current approach is valid for grassland and cropland. Field tests in several countries confirmed the practicability and reliability of the method. At field scale, soil structure is a crucial, management induced criterion of agricultural SQ. At the global scale, climate controlled hazard indicators of drought risk and soil thermal regime are crucial for SQ and crop yield potentials. Final rating scores are well correlated with crop yields. We conclude that this system could be evolved for ranking and controlling agricultural SQ on a global scale.
Article
Full-text available
Crop yield is related to soil compaction and water availability. In periods with scarcity of rains, water deficit to plant and soil resistance to root penetration are the main factors which cause yield loss. The way they affect biological processes in crops is already well understood; nevertheless, when and with what intensity they act are difficult questions to answer, above all in relation to resistance penetration, since studies do not duly consider its dynamic behavior. The declared hypothesis is that the time for the resistance penetration to reach a restrictive value is a consequence of the state of compaction and is related to plant response. The penetration resistance was estimated throughout the growing phase of the bean plant crop (Phaseolus vulgaris) as a function of soil moisture at different compaction levels (chisel plowed; no-till and no-till with additional compaction). The results obtained confirm the hypotheses of this study. Data showed that the time for the resistance to penetration to reach the value of 2 MP is different among the compaction levels and is directly related to the grain yield. Chisel plowing provides a significant increase in grain yield when the soil is high compacted. The analysis of time for the evolution of resistance to penetration at a critical value is a promising strategy with predictive potential for the effect of soil compaction on crops. Introduction The expansion of no-till system in the world has been accompanied by increasing use of agricultural machinery, whose continued traffic intensifies soil compaction, especially in inappropriate soil moisture conditions and can reduce crop production. Reductions in yield of bean greater than 50% were observed in the no-till when it was compacted by traffic (Collares 2005). Reduced production due to soil compaction has been reported in several other crops (Secco et al. 2005; Freddi et al. 2008). On the other hand, attempts to reduce soil compaction by plowing or chiseling not always were advantageous (Secco et al. 2004; Marcolan and Anghinoni 2006). Various physical properties have been related to crop response in the attempt to define critical physical limits. Using crop yield as a reference, Reinert et al. (2001) established restrictive values of soil bulk density as a function of the clay content. These levels have been refined with the association of studies of various other researchers who studied the physical quality of the soil by means of the least limit water range (LLWR) (Reichert et al. 2009), which associates information of critical aeration porosity and resistance to penetration. The great difficulty has been in establishing limits for these indicators which characterize a state of compaction which is harmful to crops. More than that, the greatest challenge has been in describing relations between one indicative piece of data and plant response, in a way that the relationship or model preserves the sensitivity between the cause and the effect in other situations of its application. The hypothesis is that values which indicate restriction from resistance to penetration occur at different times among the compaction levels, and there is a relationship between the grain yield of the bean plant and the time for resistance to penetration to reach restrictive conditions. The objectives of this study are: (i) to generate equations of soil resistance to penetration as a function of soil moisture and estimate soil resistance to penetration during the bean plant growth period; (ii) quantify the period of time which passes for soil moisture to decrease from a moisture condition after rain or irrigation up to the moisture condition in which resistance to penetration reaches a critical value; (iii) relate grain yield with the period of time which passes for resistance to root penetration to reach a critical value.
Article
Full-text available
Soil compaction has increased during recent years due to the traffic with increasingly heavier machinery. We evaluated the effect of soil compaction on soil penetration resistance, rooting depth, light interception, radiation-use efficiency (RUE) and yield of three different cultivars of winter wheat (Triticum aestivum L.). On loamy sand two compaction treatments (PAC-1 and PAC-2) and a no compaction reference treatment (REF) were applied. PAC-1 was intended to affect primarily the subsoil whereas PAC-2 was intended to affect primarily the topsoil. PAC-2 showed the highest and REF the lowest penetration resistance in the topsoil, respectively. In the subsoil both compaction treatments showed higher penetration resistances than REF. In comparison with REF, the compaction treatments decreased the estimated effective rooting depth by ca. 10, 20 and 50 cm in the three winter wheat cultivars tested, equivalent to decreases in the available soil water in the root zone of up to ca. 90 mm. These differences indicate some genetic variation in the ability of cultivars to penetrate compacted soil, although the interaction between compaction treatment and cultivar was not significant. Due to almost sufficient precipitation, the impairment of root penetration resulted in a minor yield decrease of ca. 9% of grain yield in PAC-2 and ca. 8% of total dry matter (DM) in both compaction treatments. The latter was attributed to decreases in interception of light and to efficiency of light energy conversion into biomass. The RUE was positively correlated with an estimated effective rooting depth across cultivars, while DM yield was not. This correlation probably was a result of restrictions on stomatal opening mediated by drought stress and abscisic acid produced in the root system in response to occasional soil drying. Root-sourced signals, triggered in a direct response to soil compaction, may have contributed.
Article
Full-text available
Despite major advances in remote sensing and soil-landscape modelling, the use of visual soil examination and evaluation (VSEE) techniques in the field remains a crucial component of soil assessment and management packages for farmers in rural Australia. Of particular value are techniques for the rapid assessment of soil structural form and stability, which are fundamental issues affecting the ability of soil profiles to accept and store water in farming systems constrained by drought. An improved soil appraisal framework for farm evaluation, usable for all crops, derived from the successful VSEE-based ‘Cotton SOILpak’ system, is proposed. It has the potential to enhance the ability of farm businesses to deal with four soil-related issues; annual profitability, maximising land values, minimising the impact of increasing input costs, and negotiation of favourable outcomes for themselves and the local community when confronted by competing land uses. An overview is given of the proposed technical contents of the new scheme for ‘whole-farm soil assessment and management planning’, which is based on a blend of VSEE methods, modern soil databases, and extra laboratory testing where appropriate. Also outlined are the associated human resource requirements and organisational structures required to deliver practical and ethical soil management outcomes to farmers and the nation.
Chapter
Full-text available
The industrialization of agriculture and the concurrent increase in societal concerns on environmental protection and food quality have put focus on agricultural management and its impact on soil quality. Soil quality involves the ability of the soil to maintain an appropriate productivity, while simultaneously reducing the effect on the environment and contributing to human health. This development has changed society’s expectations to science and there is an urgent need to improve the communication among researchers from different scientific disciplines. The interaction of scientists with decision-makers is a topic of utmost relevance for future developments in agriculture. Reflexive objectivity denotes the exercise of raising one’s consciousness of the cognitive context, i.e. societal priorities and the values and goals of the researcher. The term sustainability comprehends the priorities in the cognitive context and thus constitutes a valuable tool for expressing the basis of scientific work. Soil quality evaluations should include awareness of the stability of any given quality attribute to disturbance and stress. This implies addressing resistance and resilience of the soil functions and/or the physical form in question. Most existing literature on soil quality focuses on assessment of soil quality rather than the management tools available to influence soil quality. Identification of management thresholds rather than soil quality indicator thresholds is suggested as an important means of implementing the soil quality concept. The major challenges facing modern agriculture include proper nutrient cycling, maintained functions and diversity of soil, protection of an appropriate physical form, and avoidance of chemical contamination. It is suggested that these challenges and problems as related to the soil quality concept are discussed in the framework expounded above.
Article
Full-text available
A model has been presented to illustrate the way in which the influence of exchangeable Na on the fundamental processes of dispersion and flocculation on Na-Ca systems affects the various soil physical properties in the field. Most cultivated soils slake (breakdown into microaggregates) when subjected to rapid wetting, giving rise to a surface seal and a reduction in infiltration rate. However, slaking alone may not neccessarily reduce the soil's productivity, e.g. surface aggregates of the highly productive self-mulching black earths slake even when in the virgin state. If dispersion follows slaking, in most cases it will lead to poor physical properties which may manifest as poor drainage, surface crusting, hardsetting and poor trafficability or workability of the soil and eventually lead to reduced crop yields. It is the dispersion phase that is affected by the presence of excessive sodium on the exchange complex of the soil, and this may have a profound effect on the soil's physical properties and behaviour.This paper reviews the possible mechanisms by which excessive sodicity may manifest in undesirable soil physical behaviour. It also attempts to relate observations made in the laboratory on pure Na-Ca-clay systems to the behaviour of the soil in the field. The effect of sodium on the dispersive behaviour of a soil is discussed in relation to its hydraulic conductivity and the processes of infiltration, redistribution and evaporation of water which in turn affects the subsoil water storage in a soil profile. The presence of sodium is also discussed in relation to changes in soil strength characteristics, the soils workability and ease of tillage and ultimately the soil's productivity. Data are presented which show that the validity of a threshold ESP and the exclusive use of ESP as a measure of sodicity are open to question.
Article
Full-text available
Soil compaction is an important component of the land degradation syndrome which is an issue for soil management throughout the world. It is a long standing phenomenon not only associated with agriculture but also with forest harvesting, amenity land use, pipeline installation, land restoration and wildlife trampling. This review concentrates on the impact of soil compaction on practical soil management issues, an area not previously reviewed. It discusses in the context of the current situation, the causes, identification, effects and alleviation of compaction. The principal causes are when compressive forces derived from wheels, tillage machinery and from the trampling of animals, act on compressible soil. Compact soils can also be found under natural conditions without human or animal involvement. Compaction alters many soil properties and adverse effects are mostly linked to a reduction in permeability to air, water and roots. Many methods can be used to measure the changes. In practical situations, the use of visual and tactile methods directly in the field is recommended. The worst problems tend to occur when root crops and vegetables are harvested from soils at or wetter than field capacity. As discussed by a farmer, the effects on crop uniformity and quality (as well as a reduction in yield) can be marked. By contrast, rendzinas and other calcareous soils growing mainly cereals are comparatively free of compaction problems. The effect of a given level of compaction is related to both weather and climate; where soil moisture deficits are large, a restriction in root depth may have severe effects but the same level of compaction may have a negligible effect where moisture deficits are small. Topsoil compaction in sloping landscapes enhances runoff and may induce erosion particularly along wheeltracks, with consequent off-farm environmental impacts. Indirect effects of compaction include denitrification which is likely to lead to nitrogen deficiency in crops. The effects of heavy tractors and harvesters can to some extent be compensated for by a reduction in tyre pressures although there is concern that deep-seated compaction may occur. Techniques for loosening compaction up to depths of 45 cm are well established but to correct deeper problems presents difficulties. Several authors recommend that monitoring of soil physical conditions, including compaction, should be part of routine soil management.
Article
Full-text available
Soil survey information combined with exploratory simulation modeling was used to define indicators for sustainable land management. In one soil series in the Netherlands (the genoform), three different phenoforms were formed as a result of different management practices. Locations were identified using a soil map and interviews with farmers. Organic matter, bulk densities, and porosities were significantly different for the three phenoforms: biodynamic management (Bio), conventional management (Cony), and permanent grassland (Perm). By applying a dynamic simulation model for water movement, crop growth and N dynamics, the three phenoforms were analyzed in terms of sustainability indicators by defining four scenarios based on productivity and N leaching to the groundwater. (i) potential production, (ii) water-limited production, (iii) current management, and (iv) the environmental scenario. The latter was divided into EnvA: never exceeding the N-leaching threshold of 11.3 mg L-1; EnvB: exceedance occurring in one out of 30 yr; and EnvC: exceedance occurring in three out of 30 yr. Biodynamic management obtained the lowest yield under current management, while yields for Penn were highest. EnvA could not be reached for Penn as a result of high mineralization rates. Obtainable yields for scenarios EnvA, EnvB, and EnvC differed substantially, illustrating the importance of selecting 'acceptable' risks in environmental regulation. The presented methodology demonstrates the importance of pedological input in sustainability studies.
Article
In a maize field, one inter-row out of two was compacted two years down to 30-cm depth. This compacted inter-row (CIR) had a low root density down to 85-cm depth, while the soil below the row and the non compacted inter-row (NCIR) was densely rooted. Soil water status was monitored in each of these three compartments using tensiometers, neutron probe and gravimetric measurements. Both years, the rate of water extraction was about one half in the CIR compared with the row and the NCIR. As a consequence, appreciable differences in soil water potential were observed between colonized and sparsely colonized zones of each layer. These horizontal gradients were steeper than the vertical gradient between layers. This calls into question the suitability of one-dimensional models of water extraction for non-regular root systems, which are common in the field.
Article
Within-field variability in crop yield is subject to research within the framework of precision agriculture. The objectives of this study were to investigate relationships between crop yield and soil structure at the field level, and to evaluate whether field-saturated hydraulic conductivity could be used as a simple and quickly measurable indicator of crop yield. We hypothesized that the long-term average crop yield is influenced by the subsoil properties. Measurements were carried out on three fields in Sweden, at three geo-referenced locations (representing a high-, medium- and low-yielding zone, respectively) on each field. We measured significantly lower field-saturated hydraulic conductivity, Kfs, in low-yielding zones than in high- and medium-yielding zones. Aggregate mean weight diameter tended to be higher and bulk density larger in low-yielding zones, and soil structure was more blocky. Field-saturated hydraulic conductivity showed to be a good indicator of (low) yield. A model with a high R2-value was found that explained yield as a function of Kfs, on the basis of relative values. Our results indicate that degraded soil structure was the reason for low yield. The findings further suggest that subsoil plays an important role for temporally stable within-field features. The results have implications for precision framing in practice, in that (i) soil structure should be accounted for, and (ii) attention should be paid to subsoil properties. Further research is needed to generalize the findings presented here.
Article
A morphological approach and soil porosity have been used to evaluate the effect of compaction and climate on the soil structure of a loamy soil in a reduced tillage system. The study was carried out between 2000 and 2006 as part of the long-term ‘‘cropping systems and soil structure’’ experiment conducted in Estrées-Mons in northern France. Soil hydraulic, mechanical and pore morphological properties were also measured to characterise the effects on soil structure dynamics. A complementary characterisation of the soil structure was conducted on a microscale. The method for morphological description of the soil macrostructure was well suited to studying soil structure dynamics in reduced tillage systems. Results showed that the soil structure in the layer without tillage depended in the first instance on compaction intensity. Structural porosity was partly preserved in the cropping system with little compaction. In contrast just one operation, such as the harvest of sugar beet (Beta vulgaris L.), was sufficient to reduce structural porosity for 5 years even though no further compaction occurred during this period. Morphological analysis revealed the evolution of highly compacted zones under the effects of weather conditions. Platy soil structures were systematically observed in the upper part of the highly compacted zones under the tilled layers, with cracking slowly penetrating deeper into the soil with time. The structure types observed corresponded to specific soil properties resulting from the transformation of the soil structure over time. A micromorphological assessment was performed to get detailed information about the network of cracks. The morphological characterisation showed that a visual morphological approach was insufficient for revealing the entire network of cracks.
Article
Compacted and well-structured sites, on a Vertisol used for irrigated cotton production, were compared using a range of procedures for assessing soil structural form. The techniques considered were: visual/ tactile assessment using the SOILpak score, shear strength, penetration resistance, core bulk density and air-filled porosity, clod shrinkage analysis, and image analysis. All of the methods under consideration distinguished compacted soil from well-structured soil, including core bulk density, which had previously been thought of as a poor measure of soil structure in Vertisols. The simple SOILpak scoring procedure was shown to have great potential as a tool for land managers. Soil factors known to directly affect root growth, mechanical impedance and aeration, correlated well with the indirect procedures. The cheaper methods (SOILpak score and core bulk density determination) related most strongly to shear strength at the reference water content (plastic limit). The SOILpak score was more strongly related to air-filled porosity than clod shrinkage analysis or image analysis; shear strength had the same predictive power as the SOILpak score for estimating air-filled porosity. However, an advantage of using resin-impregnated soil monoliths and the SOLICON image analysis system is that the samples are big enough to represent a large proportion of the root-zone. Staining of the soil with a Rhodamine dye solution provided images that were too coarse for the routine determination of SOLICON parameters, but it is a useful and rapid procedure for highlighting those macropores that are connected with the soil surface. Clod shrinkage parameters underestimated soil air-filled porosity where compacted aggregates were interspersed with finely aggregated soil.
Article
Agricultural land evaluation is hampered by inadequate procedures for assessing the severity of soil compaction. Therefore, the ‘SOILpak scoring procedure’ has been developed within the Australian cotton industry to allow semi-quantitative assessment of soil structural form. It allows compaction severity in Vertisols to be separated into as many as 20 categories on a scale of 0.0 (severely compacted) to 2.0 (excellent structure for root growth). The procedure is based upon visual assessment of soil samples in the field as they are pulled apart by hand. The SOILpak scoring system is well accepted by advisory staff because of its speed and simplicity. However, there have been some problems with operator bias, and an inability to deal with continuity of vertical macropores, degree of encroachment of under-furrow compaction into the ridges where cotton is planted, and the presence of thin smeared layers. This paper presents a modified SOILpak scoring procedure that addresses these problems. Also, the SOILpak scoring procedure has been integrated with terminology in the ‘Australian Soil and Land Survey Field Handbooks’ so that it can be used by soil surveyors in other areas.
Article
Soil compaction is generally regarded as negative for crop growth, although many studies show a curvilinear relationship between bulk density and crop yield. In the literature, there are few systematic studies of differences between crop species in their response to compaction. This study used results from short-term Swedish field experiments to analyse the sensitivity of different crops to compaction. The crops included were barley (Hordeum vulgare L.), horse bean (Vicia faba L.), oilseed rape (Brassica napus L.), oilseed turnip rape (Brassica rapa ssp. oleifera (DC.) Metzg.), oats (Avena sativa L.), peas (Pisum sativum L.), potato (Solanum tuberosum L.), rye (Secale cereale L.), sugar beet (Beta vulgaris L.), and wheat (Triticum aestivum L.). In total 39 experiments were analysed, in two series with spring-sown crops and one with autumn-sown crops, all on soils loosened by mouldboard ploughing. The experiments included different levels of tractor traffic applied track-by-track at the time of seedbed preparation, and a control treatment with no traffic. Bulk density was determined after traffic and expressed as degree of compactness (DC), which is the bulk density in percentage of a reference density. With moderate recompaction, wheat and barley showed a yield increase compared with untrafficked soil, while other crops showed little or no yield increase on average. Oats reacted more negatively to compaction than wheat and barley. Monocots generally had a higher optimum DC than dicots, but the differences were small. Yield losses at high DC values were greater for dicots, especially pea and horse bean crops, although for sugar beet and oilseed rape there was no clear difference compared with cereal crops.
Article
Abstract Increased awareness of the role of soil structure in defining the physical fertility or quality of soil has led to the need for a simple assessment relevant to the environmental and economic sustainability of soil productivity. A test is required that is usable by farmer, consultant and researcher alike. Here an assessment of soil structure quality (Sq) is described which is based on a visual key linked to criteria chosen to be as objective as possible. The influences of operator, tillage and crop type on Sq value were tested. The test takes 5–15 min per location and enough replicates were obtained for statistical comparison of data sets. The assessments of individual operators were influenced to an extent by differences between fields, making the use of multiple operators desirable. Differences in soil management were revealed by the test and related to differences in soil physical properties (bulk density, penetration resistance and porosity) and crop growth. Indicative thresholds of soil management are suggested. The assessment should be viewed as complementary to conventional laboratory assessments of soil structure. Visual soil structure assessment can indicate to the soil scientist where to sample and what soil measurements are likely to be worthwhile.
Article
This paper aims to provide guidance for field practitioners on the vulnerability of different subsoils to compaction under different field conditions and on the tyre pressures necessary to reduce or avoid damage. It also indicates ways of identifying situations where some compaction alleviation may be necessary to improve subsoil conditions and methods for alleviating subsoil compaction problems, without increasing the risk of more extensive compaction damage in the future.
Article
Penetration resistance, bulk density, soil water content and root growth of oats were intensively studied in a tilled and an untilled grey brown podzolic loess soil. Bulk density and penetration resistance were higher in the top layer of the untilled soil compared with the tilled soil. In the latter, however, a traffic pan existed in the 25–30 cm soil layer which had higher bulk density and penetration resistance than any layer of the untilled soil. Above the traffic pan, rooting density (cm root length per cm3 of soil) was higher but below the pan it was lower than at the same depth in the untilled soil. Root growth was linearly related to penetration resistance. The limiting penetration resistance for root growth was 3.6 MPa in the tilled Ap-horizon but 4.6-5.1 MPa in the untilled Ap-horizon and in the subsoil of both tillage treatments. This difference in the soil strength-root growth relationship is explained by the build up of a continuous pore system in untilled soil, created by earthworms and the roots from preceding crops. These biopores, which occupy < 1% of the soil volume, can be utilized by roots of subsequent crops as passages of comparatively low soil strength. The channeling of bulk soil may counteract the possible root restricting effect of an increased soil strength which is frequently observed in the zero tillage system.
Article
Groundwater vulnerability assessment is a key element of any groundwater protection scheme. In Ireland, groundwater vulnerability is determined mainly according to the thickness and permeability of the subsoils (glacial tills and other superficial deposits). The relative permeabilities of the subsoils are assessed qualitatively as high, moderate or low. To improve the robustness of the groundwater protection scheme, research was carried out into subsoil properties with the aims of refining the permeability ratings, and of improving the way in which subsoil permeability classes are assigned. This research focused on subsoils in the low and moderate permeability categories, mainly tills. Important issues investigated were the relationship between permeability and the grain size distribution of the subsoil, description of subsoils for permeability classification, correlation between permeability and indicators of aquifer recharge, and suitable field and laboratory methods for measuring subsoil permeability. A standard system for describing subsoils was selected, namely BS5930:1999, the choice being influenced by the familiarity of this system among the main users of the vulnerability maps. Analysis of subsoil field descriptions and grain size data indicate that those samples identified as 'CLAY' on the basis of BS 5930 correspond to the low permeability category, and tend to have more than 13% clay size particles. The permeability values obtained from each method are compared and indicate that the numerical boundary between moderate and low permeability lies in the region of 10-9 m/s. Differences between the results from laboratory and various field permeability test methods can be explained by differences in scale and by the presence of discontinuities. The research was successful in refining the permeability ratings and thereby in making the vulnerability maps more defensible against possible challenges. This research has improved the way permeability maps are produced in Ireland, and may prove useful in other countries where permeability data are scarce and mapping relies largely on field assessment of subsoils.
Article
In France, agronomists have studied the effects of cropping systems on soil structure using a field method based on a morphological description of soil structure. In this method, called ‘‘profil cultural’’ or soil profile in English, the soil structure of the tilled layer is observed on a vertical face of a pit. Subsoil and more especially the transition layer between topsoil and subsoil have not always been given specific onsideration. However, these layers undergo the effect of cropping systems through soil compaction or smoothing/smearing. A more accurate quantification of earthworm macropores and cracks in the transition layer would enable a more precise evaluation of the agronomical potential of the soil, manifest in root development or water retention. Thus, the aim of this paper is to present the profil cultural method in detail, along with the improvements we have made to quantify the ability of roots to penetrate compacted zones in the transition layer. We propose two indicators: (i) number of earthworm burrows per m2 counted on a horizontal surface at the bottom of the transition layer in the soil pit (ii) cracking quantified by taking a 50-mm � 50-mm � 100-mm sample of soil from the transition layer and examining the number of cracks. Results from experiments on different tillage treatments are used to demonstrate why it is worthwhile to take into account cracks and earthworm activity. Soil profiles were examined in mouldboard ploughed and no tillage fields, and described using the profil cultural method and the new indicators. Root maps were also traced to observe the effect of soil structure on root growth. Preliminary results show that the classification of cracking and the quantification of the number of earthworm burrows per m2 can explain observed root development in subsoil. This first approach towards a better observation of subsoil structure and the effect it has on roots needs to be confirmed through further research, and especially via quantification and scoring of soil structure impact on roots.
Article
Spade methods to visually evaluate soil structural quality (Sq) are simple, quick, cheap and can be used by farmers, gardeners, consultants and the scientific community. However, European and Brazilian users of one such method, viz. visual evaluation of soil structure (VESS) which is a development of the Peerlkamp test, have been concerned about its subjectivity. The method of soil slice break-up and operator influence on scores have been questioned. Thus, our aim was to make soil scoring by the VESS technique more objective and thus to revise the scoring guide. We compared scoring with normal breaking up of the soil slice by hand with scoring after breaking up the slice by dropping (drop shatter) to make the soil break-up more operator independent. After slice break-up, aggregates were split by hand and their internal porosity was evaluated to develop the use of visible porosity as an aid to scoring. This proved inconclusive on its own, so a method of reducing larger aggregates to 1.5–2.0 cm core fragments and describing their shape and porosity was developed to score soil Sq. Breaking up a spadeful of soil by hand or by dropping resulted in the same Sq score. The method of reducing aggregates and evaluation of their shape improved VESS, particularly in the middle range of soil quality and the revised chart is shown. VESS was sensitive to changes in Sq in layers within the profile and its use for diagnosing Sq in different layers allows targeted soil improvement by tillage.
Article
The nature of soil disturbance required to alleviate soil compaction in a range of agricultural and land restoration situations is identified. Implement geometry and adjustments required to achieve the desired brittle or tensile deformation of compacted soil are discussed. Field operating procedures to achieve the required degrees of soil fissuring, loosening or soil unit rearrangement using the power units and equipment available are described. A new progressive loosening technique is identified for use within deep, extremely compacted soil profiles. Emphasis is given to the importance of making visual field checks across the loosened soil zone at an early stage, to check the desired disturbance is being achieved. Care must be taken during subsequent trafficking operations, to minimize the risk of recompaction.
Article
Between 1978 and 1985 16 experiments tested crop response to subsoil loosening by either the Wye Double Digger or a winged subsoiler. Additionally, response to incorporation of 350 kg ha of P2O5and K2O into the subsoil was tested. Soil types were mainly well-drained light-and medium-textured soils in arable rotations. Subsoil loosening increased the yield of spring-sown crops on sandy soils in years of moderate to severe drought. Response was associated with deeper rooting and improved water extraction from the subsoil. No yield increases were recorded with autumn-sown crops which were largely grown on the medium and heavy textured soils. There was a trend towards yield reductions on deep silty soils in wetter years. At one site only did the response to phosphorus and potassium fertilizer incorporated into the subsoil exceed that of fertilizer applied to the topsoil.