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Soil health in agricultural ecosystems: Current status and future perspectives
Abstract
Humanity thrives when soils are healthy as soils provide food, fiber, shelter, and a life-sustaining climate. Awareness of the need to optimize soil functions to grow food for an expanding human population and a desire to sustain environmental quality has led to an intense interest among stakeholders and practitioners in enhancing soil health. The public has become aware of soil health only in the last few years; however, for the seasoned soil scientists and agronomists, the journey to improve soil health began a long time ago, starting with the Dust Bowl Era and later to what was called soil quality movement. This article aims to review our current understanding of soil health by examining the history and evolving definition of soil health and then exploring the best soil health indicators from the physical, chemical, and biological domains that could be used to support practices for enhancing soil functions. Improving soil health will enhance soil functions, and so the conclusion that improving soil health involves enhancing soil organic carbon is justified. We briefly review the various soil health indicators and management options for enhancing soil health and explore. the social and economic perspectives of the call for farmers to use soil health practices. We conclude the review by examining the current knowledge gaps and suggesting ways to advance soil health understanding and conversation. For the agricultural community, we present a new definition of soil health as the capacity of soils to provide a sink for carbon to mitigate climate change and a reservoir for storing essential nutrients for sustained ecosystem productivity.
... Factors that threaten the conservation and management of tropical and dryland soils and water resources include persistent drought and water scarcity exacerbated by climate variability and changes, land and soil degradation caused by deforestation, loss of organic matter resulting from inappropriate land use practices and mismanagement, and soil erosion caused by the combined effect of water and wind, which is worsened by the degree of desertification (Ahmed Hayat et al., 2022;Bouwer, 2000;Davies et al., 2015;James and Reynolds, 2007;Marques et al., 2016). Poverty, deforestation and multiple land use practices are also challenges facing better adaptation of soil and water management in the tropics, and these have been understood long time ago in the history of soil and water conservation (Greenland and Lal, 1977).Lack of adequate soil testing prior to the application of a given conservation approach , soil and land pressures (Toor et al., 2021), are also factors diminishing the effectiveness of soil water management in the tropics. ...
... Largely, there have been significant advancements regarding the physical, biological and chemical conservation approaches in recent years (Delgado et al., 2020). The primary aim of these set of approaches, was to improve and enhance soil quality, soil fertility and control soil erosion and nutrient depletion in the tropics and drylands (Toor et al., 2021). The global achievements with respect to soil and water management are much clear (Kassam et al., 2014). ...
... This entails that soil health and conservation management are interlinked and must be observed on a regular basis. The benefits of this conservation relationship include long-term soil health sustainability for managing the biotic component of soil quality (Doran and Michael, 2000;Lehmann et al., 2020;Toor et al., 2021), which is vital for enhancing dryland and humid tropical soils (Greenland and Lal, 1977). It is also vital for agricultural conservation and for restoring soil health and mitigating climate change (Jat et al., 2023). ...
Soil and water are two natural resources that deliver various functional services to humanity. Advanced soil and water management is highly needed in the tropics. This revision focused on soil and water management issues in the tropics, soil and water management linkages to major soil functional groups (soil health, soil quality, soil fertility, water quality, and soil function), soil quality management and rehabilitation, and soil quality assessment. This study revealed that soil indictors are physical, chemical and biological, reflecting a better understanding of the major soil functional groups in an integrated soil water assessment for better soil and water management in the tropics. Regular checks and balances of comprehensive soil water management can lead to reduced soil erosion, increased water use efficiency, enhanced soil nutritional content, improved infiltration and water holding capacity, minimized runoff and surface soil leaching of pesticides and inorganic chemicals to groundwater reservoirs, increased decomposition and soil organic matter, enhanced soil biodiversity, and increased plant health and food security. To make this viable, an integrated assessment of soil water indicators and the application of sustainable soil water management approaches are needed. Regular checks and balances of the current status of soil and water quality and soil fertility must be given permanent priority.
... Soils have recently become part of the global carbon agenda for climatechange mitigation and adaptation (Amelung et al., 2020). The importance of soil health was coined by the latest definition of Toor et al. (2021) as "the capacity of soils to provide a sink for carbon to mitigate climate change and a reservoir for storing essential nutrients for sustained ecosystem productivity". ...
... The organic system was more effective at storing carbon and thereby lowering CO 2 emissions into the atmosphere and presumably the different soil tillage management had a primary role in reducing direct and indirect CO 2 emissions. In fact, the present results corroborate studies showing a link between the cropland capacity to sequester carbon into soil organic matter and the implementation of management practices such as less intensive tillage operations, rotation schemes and crop diversification (Amelung et al., 2020;De Backer et al., 2009;Toor et al., 2021;van der Werf et al., 2020). Moreover, the carbon content of the organic matter as well as other constituents therein (Fig. 2a) collectively contribute to soil health by improving soil structure, water retention, and nutrient supply to crops, agricultural productivity as well as providing food sources to fauna, enhancing ecosystem services (Amelung et al., 2020). ...
... Moreover, the carbon content of the organic matter as well as other constituents therein (Fig. 2a) collectively contribute to soil health by improving soil structure, water retention, and nutrient supply to crops, agricultural productivity as well as providing food sources to fauna, enhancing ecosystem services (Amelung et al., 2020). The sustainable system was effective in promoting the preservation of organic matter, necessary in connecting environmentally sustainable agriculture with climate change mitigation (Toor et al., 2021). ...
Context: Climate change is increasingly requiring the adoption of both climate-resilient alternative crops and sustainable management practices. Millets and sorghum are increasingly recommended as alternatives to maize in addressing these issues, yet there are no studies comparing the environmental impacts of food-crop millets and sorghum with maize, under sustainable management in Mediterranean area. Objective: The present study examined for the first time the environmental and economic impacts, as well as agronomic performances, of rainfed cultivated proso millet, sorghum and maize over a three-year period under challenging climatic conditions in Emilia-Romagna region, Italy. Methods: Different kinds of trials were realized during three years of experimentation in one location in Ravenna province. The first trial aimed to compare proso millet, sorghum and maize agronomical performances and water use efficiency in a low-input system. The second trial aimed to compare soil fertility and biodiversity impacts of two different agronomical management systems (low-input and high input) for the summer crops previously described. Soil basic fertility parameters were monitored and ground dwelling arthropods were collected and analyzed using pitfall traps. The last trial of this study intended to evaluate the environmental and economic performances of the previous cereal crops cultivated in the low-input and high-input systems, applying the Life Cycle Assessment (LCA) and the Life Cycle Costing (LCC) methodologies. Results: Both organic sorghum and millet showed high potential as viable summer-crop alternatives, not only to organic maize, based on yield, water use efficiency, disease tolerance and weed competition, but also to conventional maize, based on reduced environmental and economic impacts. Positive land impacts including improved beneficial arthropod abundances and preserved soil fertility were evident under organic management. In fact, the comparative LCA and LCC, carried out with primary data from conventionally cultivated maize and sorghum within central-north Italy and the organic experimental field under investigation, showed that the Global Warming and Eutrophication Potential, were comparable between the organically cultivated crops and significantly lower than conventional maize and sorghum. Conclusions: The results highlighted the potential of sorghum and millet cultivation as rainfed summer-crop alternative to maize in climate-change context, especially in low-input agronomical systems. In particular, under rainfed, organic management over three years, proso millet yielded consistently. Implications: Under the sustainable practices of the present study, proso millet outperformed maize for yield and WUE stability, as well as potential costs saved, related to the production amount per unit area and potential revenue.
... Since the soil exhaustion crisis of the 19th century, changes in soil fertilization practices reinforced by the invention of the Haber-Bosch process have markedly altered soil physics and biology as well as soil chemistry (Toor et al., 2021). The physical and biological properties of soil are now recognized as critically important to plant health (Feller et al., 2012;Nwokolo et al., 2021;Kopittke et al., 2022;Allen et al., 2023). ...
... The physical and biological properties of soil are now recognized as critically important to plant health (Feller et al., 2012;Nwokolo et al., 2021;Kopittke et al., 2022;Allen et al., 2023). These soil qualities have degraded during the abandonment of traditional farming practices that had focused on maintaining and cycling soil nutrients (Toor et al., 2021). For example, the complexity of microbial communities in soil can keep plant pathogens in check. ...
... The structure of soil is assured in large part by the maintenance of organic content, allowing the soil to confer its major services to plants and the environment (including water holding and filtration, nutrient cycling, decomposition and recycling of organic materials, and production of biomass) (Hu et al., 2023). Yet, in 2015, about one-third of the world's soils had been classified as "degraded" (Toor et al., 2021). Unfortunately, efforts to rectify soil health are increasingly in conflict with other uses of biomass in the multitude of initiatives to recycle biomass. ...
One Health professes that the health of organisms is interconnected through the exploitation of planetary resources, trade, and transportation, in particular. The impetus for the emergence of this concept in the early 2000s was knowledge of the epidemiology of zoonotic diseases that put humans at risk to diseases carried by animals. In spite of the intended comprehensiveness of One Health, the place of plant health in this concept is vague, and few issues about plant health are debated in the scientific literature related to One Health. Here, we explore the history of concepts related to One Health in an attempt to understand why there is this schism between the plant sciences and the medical and veterinary sciences beyond the prism of zoonotic diseases. We illustrate the rich history of concepts in the plant sciences concerning the oneness of plants, animals and humans, and the debates about the definition and scope of sustainability that are precursors to One Health. These concepts continue to be foundations for research and development, particularly for food security and food safety. The emergence of these concepts from plant sciences was based on fundamental understanding of the food web – where plants are food for humans and animals whose digestive processes create important resources for plant growth and health. Yet, this latter part of the food web – recycling of manures in particular – was ruptured during modernization of agriculture. We explain how attaining sustainable One Health depends on restoring this part of the food web via soil stewardship, whose principal guarantors are the ensemble of actors in plant production.
... Soil aggregate stability is considered as the main soil physical indicator as it influences soil aeration, root growth, water retention, soil and water erosion, C sequestration and microbial habitat (Lal, 2007;Mondal et al., 2020bMondal et al., , 2021Sharma et al., 2022;Toor et al., 2021). A strong body of literature has been built up over the past decade, showing considerable improvement in the WSAs (ranging from 11% to 89%) in surface 0-15 cm layer under CA systems, particularly in experimental plots in South Asia ( Table 2). ...
... The soil health improvement caused by crop diversification; the third principle of CA is often overlooked, warrants further assessment, especially in view of the potential multiple benefits it can deliver. Toor et al. (2021) identified four major gaps in our knowledge on soil health assessment under CA system. These gaps included, (1) Inability of soil health parameters to factor in site/soil type information and provide standard, calibrated assessment; ...
... • Future opportunities to advance soil health assessment on a large scale include development of low-cost in situ sensors that can quickly and efficiently provide estimates for several indicators including SOC, BD, pH, soil depth, soil WHC, and EC. Toor et al. (2021) suggested the need to explore the potential of using inelastic neutron scattering to monitor SOC changes and the use of imaging techniques such as X-ray and electron microscopy to elucidate soil processes. • Where a significant increase in SOC stock is measured, it is essential to assess the impact of CA system on net additional transfer of C from atmosphere to soil, and hence measure the real climate change mitigation, rather than a spatial redistribution of organic C in soil. ...
... Dredged materials were viewed as a waste to be disposed of quickly and cheaply. Although significant improvements in erosion losses have been obtained in many countries, losses of organic topsoil remain at levels threatening soil health and national welfare [24], raising the question as to why dredged sediments are not routinely recycled back onto agricultural lands. There are of course many reasons put forth, but the toxicity of chemicals in the dredged material became a major concern for the environmental movement in the 1970s [25]. ...
... Urbanization further limits global food production capacity [113,114]. Losses of organic topsoil also threaten soil health and national welfare [24,29]. Consequently, the USDA established a soil health division in 2015. ...
The Rivers and Harbors Act of 1899 (RHA1899), the Soil Conservation Act of 1935 (SCA1935), and the Clean Water Act (CWA1972) were pivotal in managing United States (US) waters. RHA1899 provided the Army Corps of Engineers authority to regulate dredge and fill operations. SCA1935 authorized the US Department of Agriculture to combat soil erosion. CWA1972 empowered the US Environmental Protection Agency to regulate point-source pollution. The implementation of the European Soil Charter of 1972 and the 2000 European Water Framework Directive empowered Europe to address similar soil erosion and water quality problems. By 2022, improvements in erosion losses were obtained with soil conservation programs, but continued losses of organic topsoil threatened soil health, human welfare, and water ecosystems. Worldwide losses, estimated at 24 billion tonnes per year, include US and European losses of ~3 billion and 970 million tonnes per year, respectively. Approximately 60% of eroded materials are delivered to rivers and lakes threatening waters. Dredged freshwater sediments, however, have beneficial uses including restoring health of agricultural and forestry lands and water resources. National initiatives involving defense, agriculture, and environmental governmental units are proposed for recycling organic, nutrient-rich aquatic sediments in world-wide Put the Land Back on the Land programs.
... For example, these assessments include the soil management assessment framework (SMAF), the Haney soil health test (HSHT), the Soil Health Institute (SHI) and the comprehensive assessment of soil health (CASH). However, as a result of variations in the assessment methods of the various soil health indicators and the need for shortterm responsive indicators, the integration and review of new soil health indicators are essential (Stott, 2019;Toor et al., 2021). Stott (2019) noted that standardized field and laboratory protocols for sampling and analysis, in addition to a 3-5-year review and update of indicators, are crucial to understanding the soil's health status. ...
... Most of the soil indicators conceptually selected for the soil health assessment relate to crop productivity, and for those used in our assessment of soil health under biobased residues, it was sufficient. This further confirmed that sensitivity to management changes for the integrated indicators is crucial for soil health assessment (Toor et al., 2021). In addition, pH, nitrate, cation exchange capacity and nutrients are strongly correlated to at least one of the crop productivity parameters (Table 1). ...
Biobased residues are local and cost‐effective sources of soil amendments, that can efficiently provide nutrients to crops, enhance soil health, and serve as alternatives to mineral fertilizers. The objective of our study was to comprehensively evaluate soil health and crop productivity of temperate agroecosystems amended with different types of organic residues (biobased residues), including composted food waste (compost), biosolid slurry (biosolids) and liquid anaerobic digestate (digestate), compared to nitrogen fertilizer. The experiment was conducted on a silt loam soil under maize‐soybean rotation in Canada where a wide range of physical, chemical, and biological indicators were measured and integrated into a soil health score. Biobased residues resulted in about 50 to 60% increase in soil‐exchangeable potassium, and 10% soil‐exchangeable sodium over levels found in nitrogen fertilizer. Soil microbial biomass and the capacity of soil microbes to utilize carbon substrates differed among growing seasons but not among amendment types ( p >0.05). Crop productivity was similar among amendment types ( p >0.05). We found that the soil health score of biosolids was positively correlated with shoot and root biomass and negatively correlated with shoot nitrogen ( p <0.05), while that of nitrogen fertilizer was positively correlated with shoot carbon ( p <0.05). This was likely due to a variation in the availability of labile carbon and nitrogen among amendment types. Our research also suggests that temperate silt loam soil amended with biobased residues, especially biosolids, supplied sufficient nitrogen without the need for additional nitrogen fertilizer.
... Increasing SOC accumulation is of vital importance to addressing the challenges of climate change and grain security [2,3]. Moreover, SOC accumulation is key to improving soil health [4,5]. SOC can be divided into two fundamentally different fractions based on formation mechanism and persistence. ...
... The area is underlain by sandy loam categorized as a calcareous Fluvisol according to the FAO classification. The Fluvisol is the most widely distributed soil in the North China Plain, accounting for almost 20% of total cropland area and contributing to over 50% of total cereal production in China [5]. The field trial consisted of seven treatments in four replicated plots in a randomized block design. ...
Long-term fertilization affects soil organic C accumulation. A growing body of research has revealed critical roles of bacteria in soil organic C accumulation, particularly through mineral-associated organic C (MAOC) formation. Protists are essential components of soil microbiome, but the relationships between MAOC formation and protists under long-term fertilization remain unclear. Here, we used cropland soil from a long-term fertilization field trial and conducted two microcosm experiments with ¹³C-glucose addition to investigate the effects of N and P fertilizations on MAOC formation and the relationships with protists. The results showed that long-term fertilization (especially P fertilization) significantly (P < 0.05) increased ¹³C-MAOC content. Compared with P-deficient treatment, P replenishment enriched the number of protists (mainly Amoebozoa and Cercozoa) and bacteria (mainly Acidobacteriota, Bacteroidota, and Gammaproteobacteria), and significantly (P < 0.001) promoted the abundances of bacterial functional genes controlling C, N, P, and S metabolisms. The community composition of phagotrophic protists prominently (P < 0.001) correlated with the bacterial community composition, bacterial functional gene abundance, and ¹³C-MAOC content. Co-occurrence networks of phagotrophic protists and bacteria were more connected in soil with the N inoculum added than in soil with the NP inoculum added. P replenishment strengthened bacterial ¹³C assimilation (i.e., ¹³C-phospholipid fatty acid content), which negatively (P < 0.05) correlated with the number and relative abundance of phagotrophic Cercozoa. Together, these results suggested that P fertilization boosts MAOC formation associated with phagotrophic protists. Our study paves the way for future research to harness the potential of protists to promote belowground C accrual in agroecosystems.
... Soil provides physical stability, support for agriculture and contributes to the nutrient cycle, water retention capacity, storage, filtering, buffering, and transformation of compounds (Tsozué et al., 2020a;Toor et al., 2021;Sivaram et al., 2023). ...
The Sudano-Sahelian zone of Cameroon, characterized by a low annual rainfall, faces challenges in soil fertility preservation due to agricultural intensification and unsustainable practices. This study aims to evaluate the effect of trachyte and basalt powders inputs on soil and maize yield in Guiring experimental farm. Fieldwork involved collecting and describing samples of trachyte, basalt, and soil and setting up the experimental design. In the laboratory, the ground rock samples underwent geochemical analysis, and the soil samples were analysed for their mineralogical and physicochemical properties. The experiment followed a completely randomized block design with three repetitions and six treatments (T0, T1, T2, T3, T4 and T5). The soil consists of kaolinite, smectite, sepiolite, and quartz. Its texture is dominated by sand fraction, with a neutral pH (6.98). The organic matter (1.30 to 3.17 %) and total nitrogen contents (0.11 to 0.13 %) are relatively low. The concentrations of potassium, magnesium, sodium, and calcium vary from 0.10 to 0.40 cmolc kg-1, 0.72 to 5.44 cmolc kg-1, 0.13 to 0.56 cmolc kg-1, and 2.64 to 6 cmolc kg-1, respectively. The cation exchange capacity is moderate to high, ranging from 18.70 to 25 cmolc kg-1, while the available phosphorus content is high, ranging from 12.60 to 30.30 mg kg-1. The studied soils are moderately suitable for maize cultivation. Fertilization trials showed a significant improvement in maize growth and yield, within plots treated with basalt powder yielding higher (2558.64 kg ha-1 and 2931.16 kg ha-1) than those treated with trachyte powder (2362.87 kg ha-1and 2763.91 kg ha-1) and the control plots (645.83 kg ha-1). Plots treated with NPK fertilizer recorded the highest yield (3164.45 kg ha-1). Although the treatment with conventional fertiliser resulted in a relative higher yield, the advantage of using rock powders lies in their environmental benefits, long-term effectiveness, and more affordable cost.
... According to Sundar et al. [50], EC is one of the main factors determining the growth and development of rice. EC in the soil directly affects the availability of nutrients, CEC, and soil health [51]. The CEC of the PNSB-supplemented treatment was lower than that of the non-PNSB-supplemented treatment. ...
Highly saline soils negatively affect crop growth, especially rice. Although chemical approaches can be used, they damage the environment and the sustainability of the agriculture. Thus, a biological candidate should be assessed. Therefore, the study evaluated the impact of nitrogen (N)-fixing purple non-sulfur bacteria (PNSB) strains on improving soil properties, nutrient uptake, growth, and rice yield on highly saline soil in My Xuyen district, Soc Trang province. The N-fixing PNSB were hypothesized to boost soil nutrient availability and reduce soil salinity, leading to a greater rice growth and yield. A pot experiment was arranged in a completely randomized block design with two factors, including four N applying rates (100, 75, 50, and 0%) and N-fixing PNSB Rhodobacter sphaeroides (no added bacteria, single bacterial strain R. sphaeroides S01, single bacterial strain R. sphaeroides S06, and a mixture of two bacterial strains R. sphaeroides S01 and S06). The results showed that adding single strains S01, S06, and mixed strains S01 and S06 improved plant height by 4.02–10.4% (the first season) and 3.86–6.84% (the second season). Under the application of the mixture of two strains S01 and S06, the soil NH4 ⁺ increased by 31.8–50.5%, while the soil Na⁺ decreased by 16.0–25.7% in both seasons. From there, the total N uptake was also improved by 34.9–73.8% and the total Na uptake went down by 19.1–26.5% via two seasons. This led to greater rice growth and yield traits, such as the number of panicles per pot, the number of seeds per panicle, and the filled seed rate in both seasons. Ultimately, the rice grain yield was improved by 10.2–14.8% by the N-fixing PNSB under greenhouse condition. In conclusion, the current study successfully provided a potent N-fixer as a candidate for improvements of saline rice growth and soil health. Thus, this liquid biofertilizer should be further tested under field trails.
... By cultivating a variety of crops, their synergistic effects can be leveraged to enhance both the yield and quality of farmland, thus advancing sustainable agricultural development goals. Additionally, the planting of diverse vegetation promotes soil fertility and resistance, optimizes the structure of soil microbial communities, and increases soil organic carbon content, fostering a positive cycle of soil health and ecosystem well-being (Toor et al., 2021). ...
... Higher tillage frequency and ploughing to control weeds likely undermine below-ground functioning in organic systems (Tamburini et al., 2016), which may offset the benefits of pesticide-free farming (Hussain et al., 2009), organic amendments (Walder et al., 2023) and more complex rotations for soil biota (D'Acunto et al., 2018). Solutions may lie in the combination of specific practices at field scale such as reducedtillage systems, crop diversification and crop-livestock systems to create more favourable conditions for soil biota and health (Toor et al., 2021) while limiting yield losses due to weed competition (Liebman & Gallandt, 1997;MacLaren et al., 2020). ...
Finding more sustainable ways to produce food is a major challenge for humanity in the face of biodiversity extinction and climate change. Consequently, research on the ability of agroecosystems to provide multiple functions is growing. In this regard, the relative importance of organic farming and landscape‐scale measures for improving multifunctionality has recently been debated.
We investigated the effects of farming system (conventional vs. organic) at field scale, total length of hedgerows in the landscape and their interaction on the multifunctionality of 40 winter cereal fields in Brittany (France). Our multifunctionality assessment integrated 21 indicators of five agroecosystem goods: biodiversity conservation, nutrient cycling and soil structure, pest and disease regulation, food production and socio‐economic performance.
Many indicators of biodiversity conservation, pest and disease regulation, and socio‐economic performance were higher in organic than in conventional systems. However, indicators of nutrient cycling and soil structure did not improve and food production was much lower in organic systems. Total hedgerow length in the landscape had less influence than organic farming on indicators, although we observed positive interactions. Granivorous carabid abundance and semi‐net margin were highest in organic fields located in well‐preserved hedgerow landscapes.
Synthesis and applications. Our study suggests that field‐scale organic farming is necessary to promote biodiversity conservation and associated ecological functioning in crop fields, whereas landscape‐scale preservation of semi‐natural habitats alone is likely insufficient. Preservation of hedgerows in the landscape brings additional ecological and socio‐economic benefits for organic systems without compromising agricultural production. More broadly, our results call for more ambitious research into the myriad possible combinations of farming practices and agri‐environmental measures at both field and landscape scales, to improve both below‐ground and above‐ground functioning.
... In modern agriculture, soil has an important position in the food-chain and planetary health system [10,11]. Maintaining soil health is important for sustaining agricultural development and food security [12,13]. Overused pesticides can enter not only the air and water but also the soil and persist for extended periods and cause non-point source (NPS) pollution such as soil health hazards, water quality declines, and crop quality reductions [14][15][16]. ...
Biochar derived from biomass pyrolysis has proven to be an excellent material for pesticide adsorption and can be used as soil amendment for pesticide non-point pollution. However, the adsorption and desorption mechanisms for certain biochar and pesticide are still unclear. In this study, we investigated the properties of biochar derived from walnut (Juglans regia L.) shell (WSB), and used batch equilibrium method to investigate the adsorption and desorption behavior for chlorantraniliprole (CAP). The physical-chemical analysis showed that there were mainly lignin charcoal of alkyl carbon, methoxyl carbon, aromatic carbon, and carboayl carbon as the primary carbon compounds of WSB. The π - π electron donor acceptor interaction, electrostatic interaction, and hydrogen bond were the primary adsorption mechanisms of the WSB adsorption. Batch equilibrium study under 298 K showed that WSB application in the soil significantly improved the adsorption ability for CAP, and the adsorption behavior was a mono-layer adsorption process as Langmuir model fitted the adsorption isotherm data better than the Freundlich model. While Freundlich model analysis showed that WSB addition to the soil changed the isothermal adsorption line from the S style to the L style. The spontaneous degree reaction of sorbents from strong to weak was in the following order: 5%-WSB >7%-WSB >10%-WSB >1%-WSB >3%-WSB > soil > WSB, and the maximum application effect was achieved at 5 % (m/m) WSB dosage mixed with the soil. Therefore, we considered that WSB addition in soil increased its CAP adsorption capacity, and 5 % (m/m) WSB application was the best choice for CAP pollution control. These data will contribute to the adsorption mechanism and the optimal use dosage of WSB for CAP pollution control.
... The implications of soil property classification extend beyond agricultural productivity to encompass broader environmental sustainability. By assessing soil health through classification, researchers can identify soils that are capable of supporting ecosystem services, such as carbon sequestration, erosion control, and habitat provision [120]. Understanding these dynamics is essential for developing conservation strategies that enhance soil health, promote biodiversity, and mitigate climate change impacts. ...
Optimization of land management and agricultural practices require precise classification of soil properties. This study presents a method to fine-tune deep neural network (DNN) hyperparameters for multiclass classification of soil properties using genetic algorithms (GAs) with knowledge-based generation of hyperparameters. The focus is on classifying soil attributes, including nutrient availability (0.78 ± 0.11), nutrient retention capacity (0.86 ± 0.05), rooting conditions (0.85 ± 0.07), oxygen availability to roots (0.84 ± 0.05), excess salts (0.96 ± 0.02), toxicity (0.96 ± 0.01), and soil workability (0.84 ± 0.09), with these accuracies representing the results from classification with variations from cross-validation. A dataset from the USA, which includes land-use distribution, aspect distribution, slope distribution, and climate data for each plot, is utilized. A GA is applied to explore a wide range of hyperparameters, such as the number of layers, neurons per layer, activation functions, optimizers, learning rates, and loss functions. Additionally, ensemble methods such as random forest and gradient boosting machines were employed, demonstrating comparable accuracy to the DNN approach. This research contributes to the advancement of precision agriculture by providing a robust machine learning (ML) framework for accurate soil property classification. By enabling more informed and efficient land management decisions, it promotes sustainable agricultural practices that optimize resource use and enhance soil health for long-term ecological balance.
... However, numerous studies have reported an increase in the emission of CO2 and nitrous oxide because of minimum and zero tillage [142][143][144][145]. Therefore, global research is required to identify uniform trends in the effect of tillage on greenhouse gas emission [142]. Different tillage systems are used for different crop fields [148]. Table 2. Effectiveness of zero tillage and strip tillage in controlling greenhouse gas production. ...
Global warming and food insecurity are global concerns, with agriculture being a major contributor to greenhouse gas emissions. Greenhouse gases such as carbon dioxide, nitrous oxide, and methane, from agricultural activities significantly impact climate change. Approximately 24% of global greenhouse gas emissions come from agriculture. Nitrous oxide is 300 times stronger than carbon dioxide and is mainly produced from organic manure and fertilizers. Methane, another potent greenhouse gas, is released during fermentation, manure management, and burning of residues. Carbon dioxide, a major contributor to climate change, is emitted through farming practices, fertilizers, pesticides, and deforestation. Climate change affects food security by directly impacting crop production and indirectly affecting food availability, cost, and supply chains. Hunger rates have been increasing globally, emphasizing the need to control global warming to reduce food insecurity. This review highlights various mitigation strategies for controlling greenhouse gases from agriculture with improved crop productivity. Soil characterization techniques, such as X-ray computed tomography, tracer and chamber-based methods, help to understand the soil composition for greenhouse gas mitigation strategies. Soil amendments, like biochar application can effectively reduce emissions by modifying microbial activity and biogeochemical processes. Controlled irrigation practices, minimum and zero tillage, and efficient nitrogen fertilizer usage also contribute to greenhouse gas mitigation and improves crop productivity. Strategies such as slow release of fertilizers and the use of inhibitors help to increase nitrogen usage efficiency and reduce nitrous oxide emissions. Implementing these strategies globally is crucial for mitigating greenhouse gas emissions, reducing global warming, and ensuring food security.
... These practices include seed treatment, meticulous seedbed preparation, precision drilling of seeds, farmer training, and machinery maintenance to ensure plant health and yield (Carvalho et al. 2021). The "blading" and bunding technique (see Supplemental material), which shapes the soil into raised beds, is unique to vegetable farming to minimize soil runoff and maximize water retention and contrasts with the practices in row crops where turn rows may increase treated seed exposure due to soil disturbance (Toor et al. 2021). As a result, the exposure of treated seeds to the soil surface is expected to be low, as shown by the bunding technique in carrot and onion cultivation in Brazil. ...
Agricultural landscapes in Brazil provide habitat to various bird species, some of which may be exposed to pesticide-treated seeds that have not been fully incorporated into the soil during drilling. Understanding the dynamics and interactions between birds and freshly drilled fields is crucial for developing sustainable farming practices that balance agricultural food production with wildlife conservation. This study investigated the presence and abundance of birds and the availability of pesticide-treated seeds in four onion fields and seven carrot fields in the Brazilian State of Minas Gerais. Bird surveys were conducted using scan sampling and point count methods to observe diversity and behavior before and after crop drilling. For carrot and onion fields, the study found that seed incorporation rates varied according to the distance from the field edges, with close to the edge having lower rates. In carrot fields, bird monitoring showed a decrease in observed species and individuals on the day of drilling, with an increase in bird sightings after drilling. In onion fields, similar trends were observed, with the species composition changing after drilling and a significant decrease in species abundance on the day of drilling. None of the species found foraging in the field after drilling were granivorous or omnivorous. These findings indicated that carrot and onion fields offer limited food sources for granivore bird species due to high seed incorporation rates and intensive seedbed preparation. The research suggests that freshly drilled carrot and onion fields are generally unattractive to foraging birds, with low seed exposure and a reduced likelihood of contact with pesticides applied as a seed treatment.
... The dsRNA can be taken up orally or absorbed directly from the environment by soaking in a dsRNA solution. Systemic RNAi following oral uptake appears possible because nematodes have a mildly alkaline gut lumen, which prevents acid-induced nucleic acid degradation (Timmons and Fire, 1998). The systemic trafficking of dsRNA in nematodes is facilitated by the expression of the systemic RNA interference-deficient gene (SID-1), which encodes a transmembrane channel involved in dsRNA uptake from the environment and cell-to-cell translocation (Winston et al., 2002). ...
The foundation of most food production systems underpinning global food security is the careful management of soil resources. Embedded in the concept of soil health is the impact of diverse soil‐borne pests and pathogens, and phytoparasitic nematodes represent a particular challenge. Root‐knot nematodes and cyst nematodes are severe threats to agriculture, accounting for annual yield losses of US$157 billion. The control of soil‐borne phytoparasitic nematodes conventionally relies on the use of chemical nematicides, which can have adverse effects on the environment and human health due to their persistence in soil, plants, and water. Nematode‐resistant plants offer a promising alternative, but genetic resistance is species‐dependent, limited to a few crops, and breeding and deploying resistant cultivars often takes years. Novel approaches for the control of phytoparasitic nematodes are therefore required, those that specifically target these parasites in the ground whilst minimizing the impact on the environment, agricultural ecosystems, and human health. In addition to the development of next‐generation, environmentally safer nematicides, promising biochemical strategies include the combination of RNA interference (RNAi) with nanomaterials that ensure the targeted delivery and controlled release of double‐stranded RNA. Genome sequencing has identified more than 75 genes in root knot and cyst nematodes that have been targeted with RNAi so far. But despite encouraging results, the delivery of dsRNA to nematodes in the soil remains inefficient. In this review article, we describe the state‐of‐the‐art RNAi approaches targeting phytoparasitic nematodes and consider the potential benefits of nanotechnology to improve dsRNA delivery.
... The soil health assessment is an increasingly relevant concern for farmers and researchers worldwide, as it plays a key role in the sustainability and productivity of production systems [1]. Through this analysis, efficient management practices can be identified, which ensure a healthy environment for plant development ...
... Soils, regarded as the foundational bedrock underpinning food and agricultural production security, play a critical role in providing plants with essential elements-nutrients, water, and structural support for their intricate root systems. Recent insights accentuate the nuanced ecosystem services offered by soils, going beyond the mere sustenance of food production to encompass the vital role they play in ensuring the stability and resilience of the Earth's environment [1,2]. ...
This study aimed to elucidate the impact of phosphate-solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF) inoculation on sorghum growth within substrates derived from phosphate solid sludge, with the overarching objective of repurposing phosphate sludge to be a viable agricultural substrate. Four PSB strains (Serratia rubidaea, Enterobacter bugandensis, Pantoea agglomerans, Pseudomonas sp) were meticulously selected from phosphate solid sludge, along with two AMF strains (Rhizophagus intraradices and Funneliformis mosseae), constituting the experimental inocula. Phosphate solid sludge was judiciously blended with peat at varying volumetric proportions (0%, 10%, 20%, 40%, and 60%), providing the matrix for sorghum cultivation, and concomi-tantly subjected to inoculation with PSB and AMF. Following a meticulously monitored two-month duration, a comprehensive evaluation of diverse morphological parameters, biomass accrual, nitrogen content, total phosphorus concentration, potassium levels, calcium content, and root coloniza-tion in sorghum plants was conducted. The empirical findings underscored a discernible decline in the assessed parameters with escalating concentrations of phosphate solid sludge. Particularly noteworthy was the pronounced amelioration observed in plants inoculated with AMF in comparison to both the control and PSB-inoculated counterparts. In conclusion, the application of raw phosphate solid sludge as an agricultural substrate is deemed unsuitable, prompting the imperative need for further in-depth investigations to ascertain the nuanced intricacies underlying these outcomes.
... Soil health is defined as the capacity of soils to provide a sink for C to mitigate climate change and a reservoir for storing essential nutrients for sustained agricultural ecosystems (Toor et al., 2021). According to Tran et al. (2021), bacterial biomass, TC, and TN might be influenced by agricultural practices rather than soil types. ...
Japan is one of the top greenhouse gasses (GHGs) emitters in the world. The overuse of chemical fertilizers has resulted in polluting air, water, and soil, especially hardening the soil, reducing soil fertility, and weakening soil microbial activity, thereby affecting soil health. The Japanese government has recognized its responsibility to address agri-environmental issues in its domestic agricultural policy. This paper aims to investigate the benefits of sustainable agricultural practices (SAPs) on rice productivity and soil fertility in Shiga Prefecture, Japan. Observational data were obtained from survey questionnaires and key informant interviews. Soil samples were also collected from eight rice fields. The results from the propensity score matching technique showed that farmers’ age, land ownership, farming scale, awareness of sustainable agriculture on soil health, and awareness of receiving direct payment subsidies significantly influence farmers’ choice to implement SAPs. SAPs have lower rice productivity by 37.4 kg/10a compared to conventional farming practices. Nevertheless, the soil fertility analysed using the Soil Fertility Index (SOFIX) in SAPs (i.e., organic farming) performs significantly better than those of conventional farming practices. More specifically, the amount of bacterial biomass is higher in organic rice fields, ranging from 14.5 – 23.3 (108 cells/g) than that in conventional rice fields of 8.8 – 11.5 (108 cells/g). Total carbon (TC) is significantly higher in sustainable rice fields (14,850 – 20,074 (mg/kg) compared to that in conventional rice fields (13,560 – 19,190 mg/kg).
... An increase in atmospheric temperatures may elevate the soil C loss from accelerated SOM decomposition [12]. Climate change impacts soil health within large geographic areas in comparison with agricultural practices, which are often limited within an agricultural field [13]. Land use/land cover change can exacerbate soil health status in a changing climate [14]. ...
The concept of soil health is increasingly being used as an indicator for sustainable soil management, and even includes legislative actions. Current applications of soil health often lack geospatial and monetary analyses of damages (e.g., land development) which can degrade soil health through loss of carbon (C) and productive soils. This study aims to evaluate the damages to soil health (e.g., soil C – primary soil health indicator) attributed to land developments within the state of Illinois (IL) in the United States of America (USA). All land developments in IL can be associated with damages to soil health with 13,361.0 km2 developed, resulting in midpoint losses of 2.5 × 1011 of total soil carbon (TSC) and a midpoint social cost of carbon dioxide emissions (SC-CO2) of 2.7B SC-CO2. New developments occurred adjacent to current urban areas near the capital city of Springfield, Chicago, and St. Louis (border city between states of Missouri and IL). Results of this study reveal several types of damage to soil health from developments: soil C loss, associated “realized” soil C social costs (SC-CO2), and loss of soil C sequestration potential from developments. The innovation of this study has several aspects. Geospatial analysis of land cover combined with corresponding soil types can identify changes in the soil health continuum at the landscape level. Because soil C is a primary soil health indicator, land conversions caused by developments reduce soil health and the availability of productive soils for agriculture, forestry, and C sequestration. Current IL’s soil health legislation can benefit from this landscape level data on soil C loss with GHG emissions and associated SC-CO2 costs by providing insight into the soil health continuum and its dynamics. These techniques and data can also be used to expand IL’s GHG emissions reduction efforts from solely focused on the energy sector to soil-based emissions from developments. Current soil health legislation does not recognize that soil’s health is harmed by disturbance from land developments, and that this disturbance results in GHG emissions. Soil health programs could be broadened to encourage less disturbance of soil types that release high levels of GHG and set binding targets based on losses in the soil health continuum.
... In addition, increasing SOC stocks has also numerous direct and indirect positive impacts on soil quality and soil health, and on food production (Lal 2016). Soil health for the agricultural community has been defined as the capacity of soils to provide a sink for C to mitigate climate change and a reservoir for storing essential nutrients for sustained ecosystem productivity (Toor et al. 2021). The SOC content is the most important and universally accepted master property that determines the state of many soil physical (soil structure, density, porosity, water-holding capacity, percolation rate and erodibility), soil chemical (nutrient availability, sorption capacity and pH), and soil biological (biodiversity, microbial biomass and basal respiration) properties (Cotrufo and Lavallee 2022;Kuzyakov and Zamanian 2019). ...
The soil carbon (C) stock is comprised of the soil inorganic carbon (SIC) and the soil organic carbon (SOC) stock. A site-specific steady state equilibrium soil C stock evolves under natural conditions depending on the balance between soil C inputs (plant residues) and losses (decomposition, erosion, leaching). The SIC stock is perceived as being less dynamic than the SOC stock with uncertain effects of organic agriculture (OA) on SIC sequestration rate, and not the focus of agricultural soil and land-use management. In contrast, the SOC stock receives increasing attention due to its importance for the global climate and soil health. However, increases in the SOC stock may also alter the greenhouse gas (GHG) balance and this must be addressed in the assessment of soil C sequestration practices to mitigate climate change. The historical loss of SOC due to the conversion of natural ecosystems to agroecosystems provides an opportunity to use soil and land-use management practices to partially replenish lost SOC stocks. Topsoil (0–15 cm depth) SOC stocks have been shown to increase under OA management by 1.98–3.50 Mg C ha−1 compared to nonorganic management. But the addition of exogenous C (e.g., with manure) for this improvement and SOC sequestration for climate change adaptation and mitigation may be important. Compared to nonorganic management, topsoil SOC sequestration rates did either not differ or were 0.29–0.45 Mg C ha−1 year−1 higher under OA, respectively. However, assessments of SOC sequestration and stocks for the entire rooted soil profile are scanty but needed to fully address long-term effects of agricultural management on SOC. Lower primary soil C inputs due to lower OA yields and higher losses by tillage compared to conventional no-tillage (NT) system may result in lower steady state equilibrium SOC stocks in OA systems. There is some evidence that root C allocation is higher under OA than that under nonorganic management. More agricultural soils will be managed in the future by OA driven by increasing consumer demand. The net effects of increased soil and land-use management for OA on the global soil C stocks must be critically assessed also in relation to long-term field experiments to support the design of climate-smart and climate resilient agroecosystems. Therefore, the objectives of this chapter are to describe in detail what processes and practices result in changes in SIC and SOC stocks and sequestration in soils under OA management.
Agricultural landscapes in Brazil provide habitat to various bird species, which may be exposed to pesticide-treated seeds that have not been incorporated into the soil during drilling. Understanding the dynamics and interactions between birds and drilled fields is crucial for developing sustainable farming practices that balance agricultural food production with wildlife conservation. This study focused on the attractivity of freshly drilled onion and carrot fields to birds and the potential exposure of birds to the pesticide-treated onion and carrot seeds available on the soil surface after drilling in Minas Gerais, Brazil. Bird surveys were conducted using scan sampling and point count methods to assess diversity and behavior before, on the day of drilling, and after drilling. Carrot fields showed a decrease in observed species and individuals on the day of drilling, with an increase in bird sightings after drilling. Similar trends were observed in onion fields, with the species composition changing after drilling and a significant decrease in abundance on the day of drilling. None of the species found foraging in the field after drilling were granivorous or omnivorous. Seed exposure was assessed by counting available seeds on the soil surface at different timepoints after drilling. Seed exposure was higher in the field border than in the field center. These findings indicate that carrot and onion fields offer limited food sources for granivore bird species probably due to low seed availability and intensive seedbed preparation. The research also suggests that freshly drilled carrot and onion crops are unattractive to foraging birds, with low seed exposure and a reduced likelihood of contact with pesticides applied as a seed treatment.
Soil degradation, resulting from improper agricultural practices and chemical processes, leads to nutrient depletion and pH changes, which affect soil fertility and crop productivity. However, understanding its impact on soil health and identifying mitigation strategies are crucial for improving and sustaining agricultural production and food security. Exposure of the soil environment to abiotic stresses intensifies chemical degradation, further compromising soil health and posing threats to agricultural production. On the other hand, agronomic practices such as tillage management, cropping geometry, nutrient application, and waste handling are crucial for sustainable crop cultivation in degraded soils. In this review, we discuss the harmful effects of elevated soil pH, salinity, and heavy metal stresses on soil degradation, as well as the reduction in nutrient availability and uptake, leading to nutrient deficiency in plants. This review explores various conventional methods, particularly organic and inorganic fertilizer management, to improve nutrient uptake and translocation in plants under chemically degraded soil conditions. In addition, we discuss sensor-based precision agricultural technologies that accurately monitor soil parameters to improve soil health. The potential of microbial biostimulants and biofortification techniques to enhance soil microbial health, promote long-term soil biodiversity, and ensure sustainable plant production is also addressed.
Conservation tillage is a practice adopted worldwide to prevent soil degradation. Although there have been many studies on the impact of conservation tillage on soil quality, most studies on cultivated land in the black soil region of Northeast China are based on the physical and chemical indicators of soil. In addition, the experiment time is generally short, so there is a lack of information about long-term conservation tillage from the perspective of the physical, chemical, and biological integration of soil. A comparative analysis of the physical, chemical, and biological characteristics of soil was conducted under no-till (NT) with straw mulching and conventional tillage (CT) treatments after 19 years of field experiments. By using membership functions to normalize and render all the indicators dimensionless, and calculating the weight of each indicator through principal component analysis, the comprehensive index of soil quality can be calculated as a weighted summation. The results indicate that NT had no significant effect on soil bulk density at a soil depth of 0–20 cm. NT increased the field water-holding capacity of the 0–5 cm layer, reduced the total porosity of the 5–10 cm soil layer, and decreased the non-capillary porosity of the 0–20 cm soil layer. Compared to CT, NT significantly increased the organic carbon content of the soil in the 0–5 cm layer, comprehensively improved the total nutrient content of the soil, and significantly increased the contents of ammonium nitrogen, nitrate-nitrogen, and available phosphorus in the soil. It also significantly improved the total phosphorus content in the 5–20 cm soil layer. NT improved the microbial carbon and nitrogen content of the soil, significantly enhanced the microbial nitrogen content in the 0–5 and 5–10 cm soil layers, and reduced the bacterial species diversity in the 5–10 cm soil layer. However, the soil enzyme activities showed no significant differences between different treatments. Under the NT treatment, the evaluation of soil quality indicators, such as mean weight diameter, field water-holding capacity, non-capillary porosity, microbial biomass nitrogen, total nutrients, and available nutrients, was relatively successful. Based on the weight calculation, the organic carbon, catalase activity, fungal richness, and bacterial diversity indicators are the most important of the 22 soil quality indicators. In terms of the comprehensive index of soil fertility quality, NT increased the soil quality comprehensive index by 34.2% compared to CT. Long-term conservation tillage improved the physical, chemical, and biological properties of the soil, which significantly enhanced the quality of the black soil.
Arable land use change and ages from natural forests alter soil quality, i.e., organic carbon and nutrient losses. Landscape fosters a more complicated spatial distribution of soil quality indicators by soil erosion, resulting in deposition at the lower slope. Although the soil quality index (SQI) has been widely used to assess soil quality, studies comparing the effects of cultivation ages and slope positions on soil quality evolution are rare. Here we report variations in soil quality and corresponding indicators under different cultivation ages (15-yr, 20-yr, and 30-yr) and sloping positions (upper-, middle-, and lower-slope) in the Mollisol region of China. We found a decreasing trend occurred for the soil organic carbon (SOC) and total nitrogen (TN) with cultivation ages. Simultaneously, from upper slope to lower slope position, an increasing trend occurred for the soil fertility properties (i.e., SOC, TN, available potassium-AK, total phosphorus-TP, and available phosphorus-AP), and a decreasing trend occurred for total potassium (TK) and pH. We found that TN, pH and sand content were the most representative indicators for the minimum data set, which represents soil quality under diverse cultivation ages. Moreover, the SQI decreased with increasing cultivation ages while increasing from the upper- to the lower slope. Notably, SQI was primarily affected by the cultivation ages (14.6%) with no considering lower slope positions. While the slope position was the main contribution to SQI (21.6%) with considering lower slope
position. We highlight that although the minimum data set was the most feasible approach for assessing soil quality under different ages of cultivation in the Mollisol region. For diverse slope positions and elevations, variations in key soil quality indicators and their interactions are necessary to be re-considered and assessed due to the soil erosion and deposition processes.
The increased focus on soil quality (SQ) aims to conserve land resources and arrest land degradation. However, there are several unknowns regarding which indicators can most effectively indicate specific SQ outcomes and ecosystem functioning. For the first time, this study aims to integrate the soil morphological properties and earthworm population with physical and chemical properties and propose a comprehensive soil quality index (SQIw) to evaluate SQ across a land-use – soil type – climate gradient. Soil profile data (n = 47) covering semi-arid, sub-humid, and humid climates, three soil types (Inceptisols, Vertisols, and Alfisols) and three major land-use systems (grassland, plantation, and annual field crops) were used in this study. As a novel approach, we used a combination of expert opinion and principal component analysis to select 12 soil quality indicators (five morphological, two physical, three chemical, and two biological properties) and developed four thematic SQ indices, viz., morphological quality index (SQIm), physical quality index (SQIp), chemical quality index (SQIc), and biological quality index (SQIb) from the respective SQ indicators using the weighted additive index method. The thematic SQ indices were integrated to create SQIw for surface and subsurface soils. The SQIm showed a strong relationship with SQIp and SQIc and a moderate relationship with SQIb, indicating that the thematic SQ indices can be employed to evaluate soil quality in resource-limited regions or countries. The SQIw differentiated the effects of climate, soil type, and land use management on soil quality and showed a strong correlation with crop yield, enabling the comparison of production systems. The integration of the earthworm population to SQIw is a crucial advancement in SQ assessment, and the SQIm adds a new dimension. The proposed SQIw could be a potential precursor for emerging consensus towards a generalised and comprehensive SQI, which can be effectively used for SQ monitoring across varied land use, soil types, and climate regions.
Soil is a complex ecosystem within which many species interact and where physicochemical and geological processes occur at different spatiotemporal scales, with strong interactions taking place between ecological and management processes. Soil processes affect the qualities of the food and water that we eat and drink, the regulation of greenhouse gases, and are the foundation of our habitation and transportation infrastructures. However, it is estimated that over 2 billion hectares of lands are degraded, with a further 12 million hectares degraded each year causing the annual loss of 24 billion tons of fertile soil. Soil degradation negatively affects the well‐being of over 3 billion people, costing more than 10% of the annual global GDP via the loss of ecosystem services, and reducing the productivity of 23% of the global terrestrial area. The sustainable management of soil ecosystems is, therefore, fundamental to global food, water, and energy security, especially under increasingly unpredictable weather patterns caused by climate change. The land–water–food–energy nexus is central to sustainable development and soil inextricably links these critical domains. Stakeholders and decision‐makers in all four domains are necessarily focusing on the effects of soil degradation on climate change, water resource management, and food production as key to the development of sustainable agricultural practices and policies. A properly integrated approach to managing rural soils is thus required to ensure global water, food, and energy security, whilst increasing and protecting biodiversity. This special issue collects 15 papers on recent advances on soil physical‐, hydrological‐, and biological processes, and linkages with agroecosystem sustainability across experiments, field observations, and methodological breakthroughs.
Managing terrestrial ecosystems for agricultural production affects the climate. This can occur by: (i) conversion of natural ecosystems to agroecosystems which adds carbon dioxide (CO2) to the atmosphere, (ii) nitrogen (N) fertilizer production and use adding more greenhouse gases (GHGs), and (iii) compensating for lower yields under organic agriculture (OA) by converting additional areas of natural ecosystems. The entire food system emits currently 16.0 Gt CO2e year−1 or one-third of the total global anthropogenic GHG emissions. However, a range of site-specific practices including conventional and OA practices can be combined to reduce overall climate impacts of agricultural production. Among the practices to lessen climate impacts of conventional agriculture is replacing some of the synthetic N fertilizer produced by the Haber-Bosch process responsible for 1.2% of the global anthropogenic CO2 emissions, with less GHG-intensive manure and management of biological nitrogen fixation (BNF). In contrast, allowing some level of mineral N fertilization (e.g., 40% of current average use) would ensure that soils under OA practices are not becoming N-deficient. Enhancing soil health by combining conventional with OA practices may potentially reduce the need for adding climate-negative external inputs. Composite or integrated farming systems combining best conventional and OA practices have become promising with their ability to reduce energy use and global warming potential (GWP). Modern technologies taking advantage of scientific discoveries should be applied in both conventional and OA systems to reduce the negative and promote the positive climate effects of food production. Conventionalization of OA by increasing adopting features of conventional modes of production based on industrial farming methods can potentially reduce climate impacts. Regenerative agriculture (RA) by combining conventional with OA practices enhances ecological processes which may reduce climate effects of agriculture. Overall, many conventional and OA practices are continuously evolving and rather than adhesion to fixed sets of principles, more sustainable and climate-resilient agricultural practices should be developed for site-specific implementation.
The soil carbon (C) stock of terrestrial biomes is determined by natural (e.g., vegetation cover, soil type, climate) and anthropogenic (e.g., soil and land-use management) factors. The soil C stock is comprised of soil inorganic carbon (SIC) and soil organic carbon (SOC) stocks, with the latter mainly controlled by biome type. Data on SOC stocks for terrestrial biomes of the U.S. are often not directly available but rather for ecosystem-type groups, land use/land cover classes, land resource regions or land-use categories. The value of the SOC stock can be estimated based on the avoided social cost of C from the long-term damage resulting from carbon dioxide (CO2) emissions as increases in the SOC stock contribute to climate change adaptation and mitigation. The SOC stock is also the most important master property determining the state of many soil physical, chemical and biological properties, and among the most important soil health indicators. However, anthropogenic conversions to managed land have resulted in SOC losses of 12.2 Pg C (13.4 billion tn C) in 0–200 cm (0–79 in) depth in the U.S. over the past 300 years. Adjustments in cropland management, in particular, can recover some of the lost SOC stock with an estimated total stock of 82.6 Pg C to 200-cm (79-in) depth for the conterminous U.S. (CONUS), i.e., the 48 adjoining U.S. states on the continent of North America. To this depth, forest biomes may contain up to 40 Pg SOC (44 billion tn SOC), but large uncertainty remains. Soils of the boreal forest/taiga biome in Alaska may contain SOC stocks >10 Pg C (11 billion tn C) in 0–1 m (0–7 ft) depth, and estimates need to be improved by better data for peatlands. The SOC stocks of the temperate coniferous forest, and the temperate broadleaf and mixed forest biomes are estimated at 12.2 Pg C (13.5 billion tn C) and 17.8 Pg C (19.7 billion tn C) in 0–150 cm (0–59 in) depth, respectively. To this soil depth, the SOC stock of the tropical forest biome of the U.S. may amount to 191 Tg C (211 million tn C). The SOC stocks of shrublands and rangelands are estimated at 5.6 Pg C (6.2 billion tn C) and 12.3 Pg C (13.6 billion tn C) in 0–100 cm (0–39 in) depth, respectively. Arctic and tundra SOC stocks in Alaska may amount to 19.2 and 21.6 Tg C (21.2 and 23.9 million tn C) to 100-cm (39-in) depth, respectively. Highly uncertain are the data for SOC stocks of terrestrial wetlands including peatlands. To 150-cm (59-in) depth, 28.5 Pg C (31.4 billion tn C) may be stored in wetlands and peatlands in CONUS and Alaska. Data for SOC stocks of the total area of deserts and xeric shrublands in the U.S. have not been published. To 200-cm (7 ft) depth, cropland SOC stocks were estimated at 28.4 Pg C (31.3 billion tn C). Total SOC stock to 100-cm (39-in) depth for urban areas in CONUS was estimated to range between 1.67 and 1.84 Pg C (1.84–2.03 billion tn C). There is an urgent need to improve SOC stock estimates for the entire terrestrial biosphere of the U.S. to identify priority areas for climate change adaptation and mitigation, and enhancing soil quality and health by managing SOC sequestration and stocks. After a brief introduction, this chapter will summarize data on SOC stocks for the different biomes, ecosystems and land uses introduced in Chap. 1.
The soil organic carbon (SOC) stock of actively managed portions of terrestrial biomes of the U.S. can be maintained and/or increased by targeted soil and land-use management practices. Soils that have lost large amount of SOC in the past (carbon ‘debt’) such as cropland soils, and soils with unsaturated reactive mineral/metal-associated C pools can be particularly managed towards increasing SOC stocks. This increase is associated with many benefits including improvements in soil health and quality, soil water storage, biodiversity and biomass production while also contributing to climate change adaptation and mitigation. However, the adoption of SOC-conserving practices such as no-till (NT) and cover crops in the U.S. has been slow as these are also associated with costs to farmers, growers, ranchers and forest land owners while their economic benefits are not immediately tangible, in addition to other barriers to adoption. Here, federal and state level legislation can support the more widespread adoption of carbon farming practices in agricultural and forest land. Another lever is the increasing private sector interest in soil health and climate-friendly supply chains which may be facilitated by generating carbon offsets or credits by enhancing SOC stocks. Many companies in the U.S. have realized this potential as a business opportunity but voluntary carbon markets are in a nascent state and outcomes with regards to net zero emission commitments by corporations uncertain. Importantly, SOC credits must be standardized to build trust and confidence in the credits generated. Another approach may be adding price premiums on products from climate-smart and SOC-friendly practices indicated by a unique seal. This would have the advantage of being independent of any political change similar to the USDA seal for products from organic agriculture (OA) which is well respected in society and already in place for several decades. Consumers are becoming increasingly aware about the effects of their personal choices on the environment, and this should be leveraged for incentivizing more climate-smart and SOC-friendly consumption and use of resources. Long-term commitments over decades and longer are needed to increase and stabilize SOC stocks of terrestrial biomes in the U.S. towards adaption and mitigation of climate change. This chapter briefly summarizes evidence from the previous chapters on how the SOC stock of terrestrial biomes in the U.S. is affected by climate and global changes, and how it can be protected and enhanced by soil and land-use management practices to increase SOC sequestration. This is followed by an overview on initiatives at the federal and state level, and in industry, private and public sectors to increase the adoption of SOC-enhancing practices. The chapter concludes with a discussion on the potential of carbon farming and carbon markets to incentivize stewardship of SOC by land managers.
This document is the first deliverable from SmartSOIL and attempts to clarify some of the socio economic context and frameworks for developing soil science. A key concept that has attracted considerable interest from scientists and policy makers alike is the ecosystem service approach. In soil science, the use of an ecosystem service approach has been developed in parallel with the concept of soil functions, which also have found their way into EU policy developments such as the proposed EU Soil Framework Directive. We find that soil functions overlap with intermediate services in recent ecosystem service categorisations, such as the one used for the UK National Ecosystem Assessment. The distinction between intermediate and final ecosystem services is crucial in this respect, at least if an ecosystem service approach is supposed to serve as a basis for economic assessments of changes in service delivery due to land use or land management changes.
We further highlight the challenges in understanding the underlying complexity in processes and services and illustrated approaches that could be used to manage this complexity in order to produce results that can be of relevance in practice. This includes clarification of soil stock and (service) flow concepts that motivate (albeit theoretical) questions about the meaning of soil resilience and sustainability. As a main product of this work, we produced a comprehensive overview table that highlights the variety of ecosystem services derived from a lowland arable landscape. Central to this overview is the identification of intermediate service outcomes related to soil that are relevant to final service provision. Such information is particularly useful to identify future research needs in order to quantify and understand crucial links between ‘what soil does and provides’ and the associated final ecosystem services, which are to be valued in monetary terms for assessments of economic impacts of service flow changes due to changes in land use and management.
Soils represent the largest terrestrial sink of carbon (C) on Earth, yet the quantification of the amount of soil organic carbon (SOC) is challenging due to the spatial variability inherent in agricultural soils. Our objective was to use a grid sampling approach to assess the magnitude of SOC variability and determine the current SOC stocks in three typical agricultural fields in Maryland, United States. A selected area in each field (4000 m²) was divided into eight grids (20 m × 25 m) for soil sample collection at three fixed depth intervals (0–20 cm, 20–40 cm, and 40–60 cm). Soil pH in all fields was significantly (p < 0.05) greater in the surface soil layer (6.2–6.4) than lower soil layers (4.7–5.9). The mean SOC stocks in the surface layers (0–20 cm: 1.7–2.5 kg/m²) were 47% to 53% of the total SOC stocks at 0–60 cm depth, and were significantly greater than sub-surface layers (20–40 cm: 0.9–1.3 kg/m²; 40–60 cm: 0.8–0.9 kg/m²). Carbon to nitrogen (C/N) ratio and stable C isotopic composition (δ¹³C) were used to understand the characteristics of SOC in three fields. The C/N ratio was positively corelated (r > 0.96) with SOC stocks, which were lower in sub-surface than surface layers. Differences in C/N ratios and δ¹³C signatures were observed among the three fields. The calculated values of SOC stocks at 0–60 cm depth ranged from 37 to 47 Mg/ha and were not significantly different in three fields likely due to the similar parent material, soil types, climate, and a short history of changes in management practices. A small variability (~10% coefficient of variation) in SOC stocks across eight sampling grids in each field suggests that re-sampling these grids in the future can lead to accurately determining and tracking changes in SOC stocks.
Trust is a key ingredient of almost all market interactions. Much of the literature on the relationship between trust and market activity, however, has focused on how trust facilitates market activity rather than on how market activity affects trust. In this study, however, we investigate whether market interactions can affect the subsequent trusting and reciprocating behavior of former trading partners. Additionally, we explore the effect of personal and impersonal exchange on the trusting and reciprocating behavior of former trading partners. We find experimental evidence that suggests that positive and negative market interactions can affect such behavior. Further, we find that past market dealings only affect the trusting and reciprocating behavior of subjects who participated in an experimental market where exchanges were more personal, but did not affect trust and reciprocity between trading partners who participated in an experimental market where exchanges were more impersonal. In the market where exchanges are more personal, people exhibit higher levels of trust and reciprocity to trading partners with whom they have mostly positive market interactions than with whom they have mostly negative market interactions. However, in the market where exchanges are more impersonal, people exhibit the same levels of trust and reciprocity to trading partners regardless of the nature of their previous market interactions.
Tillage intensity affects soil microbiological activity in many ways, often driven by changes in soil organic C (SOC) content. The magnitude and direction of those changes, however, depends on inherent (e.g., soil type and texture), experimental (e.g., study duration and sampling depth) and agronomic factors (e.g., cropping system and crop residue management). This nationwide meta-analysis examines published effects of chisel plowing (CP), no-tillage (NT), and perennial cropping systems (PER) relative to moldboard plow (MP) on seven soil health indicators: SOC, microbial biomass C (MBC), microbial biomass N (MBN), soil respiration (Resp), active-C (AC), beta-glucosidase activity (BG) and soil protein (Prot) within four soil depth increments in 302 studies from throughout the United States (U.S.). Overall, converting from MP to CP primarily affected topsoil (0 to ≤ 15 cm) SOC, MBC, and Resp, whereas converting from MP to NT significantly increased all seven soil health indicators in the topsoil. Below the topsoil, NT had greater MBC, MBN, Resp, and BG relative to MP (i.e., 15 to 25-cm). The impact of NT was affected by latitude, soil order, time under NT, and cropping system. Among soil orders, management practices had the largest positive effects in Ultisols, Inceptisols, Alfisols, and Mollisols. Those effects were most noticeable at lower latitudes, in systems that included cover crops or residue retention, and in experiments conducted for at least three years. Perennial systems had a positive effect on all soil health indicators at all soil depths (0 to >40-cm). The positive response of PER systems compared to MP was enhanced at lower latitudes and in Alfisols, Inceptisols, Entisols, and Mollisols. Based on this meta-analysis, reducing tillage intensity, planting cover crop and/or minimizing crop residue removal within annual cropping systems can significantly improve soil biological health in the U.S. Finally, we demonstrate that SOC and many other biological indicators are sensitive to management practices, confirming their utility in soil health assessment.
Measurement(s)
organic material • grain yield trait • mass density of soil • concentration of carbon atom in soil • soil organic carbon sequestration rate • concentration of nitrogen atom in soil • phosphorus • potassium • pH measurement • soil cation exchange capability • electrical conductivity • soil base saturation • aggregate stability • porosity of soil • soil penetration resistance • soil infiltration rate • field saturated hydraulic conductivity • soil erosion • flood • soil nutrient leaching • temperature of soil • soil water content • available water holding capacity • parasitic weed • diseases of the cropland • pests • Lumbricus terrestris • Arthropoda • Nematoda • Bacteria • Fungi • mycorrhiza • enzyme activity • dinitrogen oxide • carbon dioxide • methane gas emission process
Technology Type(s)
digital curation
Factor Type(s)
conservation management method
Sample Characteristic - Environment
soil environment
Sample Characteristic - Location
United States of America • Canada • Germany • Brazil • French Republic • Italy • Sweden • Kingdom of Denmark • Nigeria • Argentina • Kenya • Zimbabwe • China • South Korea • Kingdom of Spain • Kingdom of the Netherlands • Greece • Kingdom of Norway • New Zealand • Russia • Australia • Ghana • Malawi • Benin • Zambia • Cameroon • Peru • Indonesia • The Philippines • Rwanda • Uganda • Togo • Guinea • Tanzania • Turkey • Moldova • England • India • Costa Rica • Switzerland • Bangladesh • Poland
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.10748210
Soil biodiversity and habitat provisioning is one of the soil functions that agricultural land provides to society. This paper describes assessment of the soil biodiversity function (SB function) as a proof of concept to be used in a decision support tool for agricultural land management. The SB function is defined as “the multitude of soil organisms and processes, interacting in an ecosystem, providing society with a rich biodiversity source and contributing to a habitat for aboveground organisms.” So far, no single measure provides the full overview of the soil biodiversity and how a soil supports a habitat for a biodiverse ecosystem. We have assembled a set of attributes for a proxy-indicator system, based on four “integrated attributes”: (1) soil nutrient status, (2) soil biological status, (3) soil structure, and (4) soil hydrological status. These attributes provide information to be used in a model for assessing the capacity of a soil to supply the SB function. A multi-criteria decision model was developed which comprises of 34 attributes providing information to quantify the four integrated attributes and subsequently assess the SB function for grassland and for cropland separately. The model predictions (in terms of low—moderate—high soil biodiversity status) were compared with expert judgements for a collection of 137 grassland soils in the Netherlands and 52 French soils, 29 grasslands, and 23 croplands. For both datasets, the results show that the proposed model predictions were statistically significantly correlated with the expert judgements. A sensitivity analysis indicated that the soil nutrient status, defined by attributes such as pH and organic carbon content, was the most important integrated attribute in the assessment of the SB function. Further progress in the assessment of the SB function is needed. This can be achieved by better information regarding land use and farm management. In this way we may make a valuable step in our attempts to optimize the multiple soil functions in agricultural landscapes, and hence the multifaceted role of soils to deliver a bundle of ecosystem services for farmers and citizens, and support land management and policy toward a more sustainable society.
More meaningful and useful soil health tests are needed to enable better on-farm soil management. Our objective was to assess the relationship between field management, soil health, and soil microbial abundance and composition (phospholipid fatty acid analysis (PLFA)) in soil collected from two fields (farmer-designated ‘good’ versus ‘poor’) across 34 diverse (livestock, grain or vegetable cropping) farms in Maritime Canada. Soil health was measured using soil texture, surface hardness, available water capacity, water stable aggregates, organic matter, soil protein, soil respiration, active carbon, and standard nutrient analysis. All soils were medium to coarse textured (<8% clay). Mixed models analysis showed that both CSHA and PLFA were able to resolve statistical differences between cropping systems, however conventional soil chemical analysis was the only testing method to resolve statistical differences between farmer designated ‘good’ and ‘poor’ fields. Principle component analyses determined management history (rotation over previous three years), but not ‘good’ or ‘poor’ field designation, to be an important determinant of soil health. Water-stable aggregates and soil respiration were positively correlated with all PLFA microbial groups, and negatively correlated with sand, P, Cu and Al. Lower-intensity management (perennial forage, mixed annual-perennial cropping), manure application and low tillage were linked to higher soil respiration, water-stable aggregates, fungi, mycorrhizae, Gram negative bacteria, and lower soil available P. Correlations between CSHA and PLFA shows promise for integrating these two tests for improved soil health assessment.
Core Ideas
Soil health metrics were sensitive in North Carolina soils.
Tillage intensity and fertility practices were especially differentiated by biological soil health metrics.
Soil health metrics associated with labile organic matter correlated well with crop yields.
Soil health (SH) refers to the ability of a soil to function and provide ecosystem services. This study reanalyzes data from long‐term agronomic management experiments in North Carolina and addresses previous conclusions regarding the utility of SH test metrics. Data for 15 SH indicators in the Comprehensive Assessment of Soil Health (CASH) framework from three long‐term trials in North Carolina were analyzed to assess effects of tillage intensity and organic vs. conventional management. This included four soil biological indicators—organic matter (OM), active carbon (ActC), respiration (Resp), and protein (Prot); four soil physical indicators—available water capacity (AWC), water‐stable aggregation (Agstab), surface and subsurface penetration resistance (SurfHard, SubHard); and seven soil chemical (fertility) indicators (P, K, Mg, Fe, Mn, Zn, pH). Corn (Zea mays L.) and soybean (Glycine max L. Merr.) yield data and SH indicator values were correlated using site‐specific and multi‐site datasets. Long‐term management practices most commonly showed significant impacts with AgStab (up to 2.2′), ActC (2.1′), Prot (2.3′), and most chemical indicators. Tillage intensity had a greater impact than organic vs. conventional management and linear regression of multi‐year mean corn and soybean yield response to tillage showed significant correlations with eight SH indicators, highest among them ActC, Protein, Resp, and Mn (R² = 0.85–0.93). Contrary to previous conclusions, CASH indicators, especially those related to labile C and N, responded well to management practices and showed utility for SH assessment in agronomic trials.
Core Ideas
Despite nationwide emphasis on soil health in the USA, current measurements lack consistency.
A meta‐analysis showed 8 of 42 soil health indicators reported >20% of time.
Only 13 indicators showed short‐term (1–3 yr timescale) responses to cover cropping.
Wide variation in soil sampling protocols suggests standardization is needed.
Translating soil health research across systems requires a common framework.
Despite a nationwide emphasis on improving soil health in the United States, current measurement protocols have little consistency. To survey assessment practices, we conducted a meta‐analysis of cover crop ( n = 86) and no‐tillage ( n = 106) studies and compiled reported indicators, cropping systems, and soil sampling protocols from each. We then analyzed which indicators significantly responded to cover crop usage after 1 yr and 2 to 3 yr. Our results showed that out of 42 indicators, only 8 were reported in >20% of studies. Thirteen indicators showed >10% relative response after 1 to 3 yr; the remainder lacked either sufficient observations or consistent results. Looking forward, we propose that emphasis should be placed on (i) pursuing dynamic indicators (e.g., aggregate stability), (ii) standardizing sampling protocols, and (iii) developing a common framework for information sharing. These efforts will generate new insight into soil health across systems, ultimately ensuring that soil health science is useful to producers and regulators.
This assessment examines the extent to which advisory services are able to address practitioners (primarily farmers) current and emerging knowledge needs about sustainable soil management (SSM) in Europe. The assessment is structured around the following components: the context of advice (policy, market, socio economic conditions, privatisation of advisory systems); the challenges that SSM presents for advice; the current and emerging practitioner knowledge needs and the existing structure and function of advisory services for SSM. The analysis reveals fragmented policy and advisory services, paralleled by the multi‐scale character of SSM and a diverse audience for advice. The challenges and opportunities this complex arena presents are analysed and suggestions made for achieving more effective advisory services for SSM, together with examples of existing approaches.
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Ecosystem services provided by soil can be supporting (e.g. providing primary production and biodiversity) or regulatory (e.g. erosion control, water infiltration, nutrient retention, atmospheric gas regulation and pest control). This chapter explains how ecosystem services benefit human welfare through these functions, addressing the role of soil in the production of food, fibre and energy, erosion control and nutrient abatement. The chapter also examines how soil regulates infiltration of water, can mitigate greenhouse gases control pests and supports biodiversity. The chapter provides an extensive review of the literature for further reading on the subject and looks ahead to future research trends in this area.
A healthy soil has the capacity to sustain biological activity, maintain environmental quality and promote plant and animal health. This chapter reviews the impact of changing climate on the key components of soil health i.e., soil physical, chemical, and biological properties. Holistically, under the nexus of climate change and farming systems, this chapter also reviews some of the key management practices that have been demonstrated to improve soil health and deliver climate benefits. To address the conundrum of building soil health under a changing climate, this chapter proposes a framework for wider implementation of sustainable management approaches for improving soil health globally. The knowledge gap relating to the practicalities of sustainable strategies requires multi-disciplinary collaboration and communications.
Sampling and analysis or visual examination of soil to assess its status and use potential is widely practiced from plot to national scales. However, the choice of relevant soil attributes and interpretation of measurements are not straightforward, because of the complexity and site-specificity of soils, legacy effects of previous land use, and trade-offs between ecosystem services. Here we review soil quality and related concepts, in terms of definition, assessment approaches, and indicator selection and interpretation. We identify the most frequently used soil quality indicators under agricultural land use. We find that explicit evaluation of soil quality with respect to specific soil threats, soil functions and ecosystem services has rarely been implemented, and few approaches provide clear interpretation schemes of measured indicator values. This limits their adoption by land managers as well as policy. We also consider novel indicators that address currently neglected though important soil properties and processes, and we list the crucial steps in the development of a soil quality assessment procedure that is scientifically sound and supports management and policy decisions that account for the multi-functionality of soil. This requires the involvement of the pertinent actors, stakeholders and end-users to a much larger degree than practiced to date.
Soil health has traditionally been judged in terms of production; however, it recently has gained a wider focus with a global audience, as soil condition is becoming an environmental quality, human health, and political issue. A crucial initial step in evaluating soil health is properly assessing the condition of the soil. Currently most laboratory soil analyses treat soils as non-living, non-integrated systems. Plant available nutrients have traditionally been estimated with methods that utilize harsh chemical extractants in testing soil for inorganic N, P, K, and micronutrients. Complementary methods, including soil texture, pH, and total soil organic matter, also do not evaluate biological soil aspects. In this paper we introduce and describe the theory behind the Soil Health Tool, focusing on two objectives: 1) to estimate plant available N, P, and K; and 2) to provide an indication of soil health with respect to nutrient and C cycling. The Soil Health Tool is an integrative soil testing approach that measures inorganic N, P, and K with a soil extractant comprised of organic acids. It also estimates potentially mineralizable N and P as influenced by water extractable organic C and N and microbial soil respiration. The Soil Health Tool was designed for use in commercial soil testing laboratories and uses rapid, cost-effective procedures. The tool also offers insight into the complex interactions between soil chemistry and biology and providing additional value to producers through improved plant available nutrient estimates as well as an indication of the soil health status as related to C, N, and P cycling.
The control of soil moisture, vegetation type, and prior land use on soil health parameters of perennial grass cropping systems on marginal lands is not well known. A fallow wetness-prone marginal site in New York (USA) was converted to perennial grass bioenergy feedstock production. Quadruplicate treatments were fallow control, reed canarygrass (Phalaris arundinaceae L.Bellevue) with nitrogen (N) fertilizer (75 kg N ha−1), switchgrass (Panicum virgatum L. Shawnee), and switchgrass with N fertilizer (75 kg N ha−1). Based on periodic soil water measurements, permanent sampling locations were assigned to various wetness groups. Surface (0–15 cm) soil organic carbon (SOC), active carbon, wet aggregate stability, pH, total nitrogen (TN),
root biomass, and harvested aboveground biomass were measured annually (2011–2014). Multi-year decreases in SOC, wet aggregate stability, and pH followed plowing in 2011. For all years, wettest soils had the greatest SOC and active carbon, while driest soils had the greatest wet aggregate stability and lowest pH. In 2014, wettest soils had significantly (p < 0.0001) greater SOC and TN than drier soils, and fallow soils had 14 to 20% greater SOC than soils of reed canarygrass + N, switchgrass, and switchgrass + N. Crop type and N fertilization did not result in significant differences in SOC, active carbon, or wet aggregate stability. Cumulative 3-year aboveground biomass yields of driest switchgrass + N soils (18.8 Mg ha−1) were 21% greater than the three wettest switchgrass (no N) treatments. Overall, soil moisture status must be accounted for when assessing soil dynamics during feedstock establishment.
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Globally soil quality and food security continue to decrease indicating that agriculture and the food system need to adapt. Improving connection to the soil by knowledge exchange can help achieve this. We propose a framework of three types of connections that allow the targeting of appropriate messages to different groups of people. Direct connection by, for example, handling soil develops soil awareness for management that can be fostered by farmers joining groups on soil-focused farming such as organic farming or no-till. Indirect connections between soil, food and ecosystem services can inform food choices and environmental awareness in the public and can be promoted by, for example, gardening, education and art. Temporal connection revealed from past usage of soil helps to bring awareness to policy workers of the need for the long-term preservation of soil quality for environmental conservation. The understanding of indirect and temporal connections can be helped by comparing them with the operations of the networks of soil organisms and porosity that sustain soil fertility and soil functions.
The living soil is instrumental to key life support functions (LSF) that safeguard life on Earth. The soil microbiome has a main role as a driver of these LSF. Current global developments, like anthropogenic threats to soil (e.g., via intensive agriculture) and climate change, pose a burden on soil functioning. Therefore, it is important to dispose of robust indicators that report on the nature of deleterious changes and thus soil quality. There has been a long debate on the best selection of biological indicators (bioindicators) that report on soil quality. Such indicators should ideally describe organisms with key functions in the system, or with key regulatory/connecting roles (so-called keystone species). However, in the light of the huge functional redundancy in most soil microbiomes, finding specific keystone markers is not a trivial task. The current rapid development of molecular (DNA-based) methods that facilitate deciphering microbiomes with respect to key functions will enable the development of improved criteria by which molecular information can be tuned to yield molecular markers of soil LSF. This review critically examines the current state-of-the-art in molecular marker development and recommends avenues to come to improved future marker systems.
Climate-smart cropping systems should be designed with three objectives: reducing greenhouse gas (GHG) emissions, adapting to changing and fluctuating climate and environment, and securing food production sustainably. Agriculture can improve the net GHG emissions balance via three levers: less N2O, CH4 and CO2 emissions, more carbon storage, and green energy production (agrifuels, biogas). Reducing the application of mineral N fertilizer is the main option for reducing N2O emissions either directly or by increasing the proportion of legumes in the rotation. The most promising options for mitigating CH4 emissions in paddy fields are based on mid-season drainage or intermittent irrigation. The second option is storing more carbon in soil and biomass by promoting no-tillage (less fuel, crop residues), sowing cover crops, introducing or maintaining grasslands and promoting agroforestry. Breeding for varieties better adapted to thermal shocks and drought is mainly suggested as long-term adaptation to climate change. Short-term strategies have been identified from current practices to take advantage of more favorable growing conditions or to offset negative impacts: shifting sowing dates, changing species, cultivars and crop rotations, modifying soil management and fertilization, introducing or expanding irrigation. Some crops could also move to more suitable locations. Model-based tools and site-specific technologies should be developed to optimize, support and secure farmer's decisions in a context of uncertainty and hazards. Most of the adaptation and mitigation options are going in the same way but tradeoffs will have to be addressed (e.g. increasing the part of legumes will be possible only with significant breeding efforts). This will be a challenge for designing cropping systems in a multifunctional perspective.
SOIL BIOLOGICAL HEALTH is a topic of great interest to sugarcane growers, although there is confusion as to what constitutes soil health. Many growers and consultants are unaware that beneficial organisms, rather than pathogens and pests, dominate the biological community in a healthy soil. Considering the vast diversity of soil organisms and their complex interactions, it is unsurprising that there is limited knowledge about how farming practices precisely impact on soil biological health, and how biological health can be achieved. The former Sugar Yield Decline Joint Venture (SYDJV) and subsequent activities have demonstrated that soil biological health represents a significant production constraint. The modern farming system (MFS), with controlled traffic, permanent beds, minimum tillage, legume break crops and crop residue retention, aims to overcome soil constraints, including soil biological health, by minimising problems arising from soil compaction, continuous monoculture and low levels of soil organic matter. In this paper we discuss key organisms that inhabit soils under sugarcane production and how soil biology responds to management practices. We highlight biological indicators of soil health, and their usefulness to growers for quantifying soil responses to changed farming practices. We outline research needs to advance the industry’s ability to manipulate soil biological health.
Slow release of nitrate by charred organic matter used as a soil amendment (i.e. biochar) was recently suggested as potential mechanism of nutrient delivery to plants which may explain some agronomic benefits of biochar. So far, isolated soil-aged and composted biochar particles were shown to release considerable amounts of nitrate only in extended (>1 h) extractions (“slow release”). In this study, we quantified nitrate and ammonium release by biochar-amended soil and compost during up to 167 h of repeated extractions in up to six consecutive steps to determine the effect of biochar on the overall mineral nitrogen retention. We used composts produced from mixed manures amended with three contrasting biochars prior to aerobic composting and a loamy soil that was amended with biochar three years prior to analysis and compared both to non-biochar amended controls. Composts were extracted with 2 M KCl at 22°C and 65°C, after sterilization, after treatment with H2O2, after removing biochar particles or without any modification. Soils were extracted with 2 M KCl at 22°C. Ammonium was continuously released during the extractions, independent of biochar amendment and is probably the result of abiotic ammonification. For the pure compost, nitrate extraction was complete after 1 h, while from biochar-amended composts, up to 30% of total nitrate extracted was only released during subsequent extraction steps. The loamy soil released 70% of its total nitrate amount in subsequent extractions, the biochar-amended soil 58%. However, biochar amendment doubled the amount of total extractable nitrate. Thus, biochar nitrate capture can be a relevant contribution to the overall nitrate retention in agroecosystems. Our results also indicate that the total nitrate amount in biochar amended soils and composts may frequently be underestimated. Furthermore, biochars could prevent nitrate loss from agroecosystems and may be developed into slow-release fertilizers to reduce global N fertilizer demands.
The '4 per mille Soils for Food Security and Climate' was launched at the COP21 with an aspiration to increase global soil organic matter stocks by 4 per 1000 (or 0.4 %) per year as a compensation for the global emissions of greenhouse gases by anthropogenic sources. This paper surveyed the soil organic carbon (SOC) stock estimates and sequestration potentials from 20 regions in the world (New and Russia). We asked whether the 4 per mille initiative is feasible for the region. The outcomes highlight region specific efforts and scopes for soil carbon sequestration. Reported soil C sequestration rates globally show that under best management practices, 4 per mille or even higher sequestration rates can be accomplished. High C sequestration rates (up to 10 per mille) can be achieved for soils with low initial SOC stock (topsoil less than 30 t C ha −1), and at the first twenty years after implementation of best management practices. In addition, areas which have reached equilibrium will not be able to further increase their sequestration. We found that most studies on SOC sequestration only consider topsoil (up to 0.3 m depth), as it is considered to be most affected by management techniques. The 4 per mille number was based on a blanket calculation of the whole global soil profile C stock, however the potential to increase SOC is mostly on managed agricultural lands. If we consider 4 per mille in the top 1m of global agricultural soils, SOC sequestration is between 2-3 Gt C year −1 , which effectively offset 20–35% of global anthropogenic greenhouse gas emissions. As a strategy for climate change mitigation, soil carbon sequestration buys time over the next ten to twenty years while other effective sequestration and low carbon technologies become viable. The challenge for cropping Geoderma j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / g e o d e r m a farmers is to find disruptive technologies that will further improve soil condition and deliver increased soil carbon. Progress in 4 per mille requires collaboration and communication between scientists, farmers, policy makers, and marketeers.
Cycling of nutrients, including nitrogen and phosphorus, is one of the ecosystem services we expect agricultural soils to deliver. Nutrient cycling incorporates the reuse of agricultural, industrial and municipal organic residues that, misleadingly, are often referred to as ‘wastes’. The present review disentangles the processes underlying the cycling of nutrients to better understand which soil properties determine the performance of that function. Four processes are identified (i) the capacity to receive nutrients, (ii) the capacity to make and keep nutrients available to crops, (iii) the capacity to support the uptake of nutrients by crops and (iv) the capacity to support their successful removal in harvested crop. Soil properties matter but it is imperative that, as constituents of ‘soil quality’, they should be evaluated in the context of management options and climate and not as ends in their own right. The effect of a soil property may vary depending on the prevailing climatic and hydrologic conditions and on other soil properties. We recognize that individual soil properties may be enhancing one of the processes underlying the cycling of nutrients but simultaneously weakening others. Competing demands on soil properties are even more obvious when considering other soil functions such as primary production, purification and flow regulation of water, climate modification and habitat provision, as shown by examples. Consequently, evaluations of soil properties and management actions need to be site-specific, taking account of local aspects of their suitability and potential challenges.
To reduce the environmental footprint of human activities, the quality of environmental media such as water, soil and the atmosphere should be first assessed. Microorganisms are well suited for a such assessment because they respond fast to environmental changes, they have a huge taxonomic and genetic diversity, and they are actively involved in biogeochemical cycles. Here, we review microbiological methods that provide sensitive and robust indicators for environmental diagnosis. Methods include genomics, transcriptomics, proteomics and metabolomics to study the abundance, diversity, activity and functional potentials of indigenous microbial communities in various environmental matrices such as water, soil, air and waste. We describe the advancement, technical limits and sensitivity of each method. Examples of method application to farming, industrial and urban impact are presented. We rank the most advanced indicators according to their level of operability in the different environmental matrices based on a technology readiness level scale.
Soils act as sources and sinks for greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4),and nitrous oxide (N2O). Since both storage and emission capacities may be large, precise quantificationsare needed to obtain reliable global budgets that are necessary for land-use management (agriculture,forestry), global change and for climate research. This paper discusses exclusively the soil emission-related processes and their influencing parameters. It reviews soil emission studies involving the mostimportant land-cover types and climate zones and introduces important measuring systems for soilemissions. It addresses current shortcomings and the obvious bias towards northern hemispheric data.When using a conservative average of 300 mg CO2e m−2h−1(based on our literature review), thisleads to global annual net soil emissions of ≥350 Pg CO2e (CO2e = CO2equivalents = total effect of all GHGnormalized to CO2). This corresponds to roughly 21% of the global soil C and N pools. For comparison,33.4 Pg CO2are being emitted annually by fossil fuel combustion and the cement industry.
Soils are integral to the function of all terrestrial ecosystems and to food and fibre production. An overlooked aspect of soils is their potential to mitigate greenhouse gas emissions. Although proven practices exist, the implementation of soil-based greenhouse gas mitigation activities are at an early stage and accurately quantifying emissions and reductions remains a substantial challenge. Emerging research and information technology developments provide the potential for a broader inclusion of soils in greenhouse gas policies. Here we highlight 'state of the art' soil greenhouse gas research, summarize mitigation practices and potentials, identify gaps in data and understanding and suggest ways to close such gaps through new research, technology and collaboration.
Science can serve as a valuable foundation for the making of public policy. For science to have this effect, it must be effectively communicated to individuals, organizations, and institutions. Effective science communication often involves frames that highlight particular aspects of a scientific finding or issue. This chapter discusses ways in which frames can be used to facilitate effective scientific communication- particularly we explore the impact of frames with regard to attention limitations, political polarization, and the politicization of science. We also highlight unanswered questions and challenges. The main lesson of this chapter is that there are certain conditions under which choosing particular frames yields more effective communication. While understanding these conditions does not guarantee success, it can help science communicators avoid common mistakes.
Policymakers and investors have perceived securing soil organic carbon as too difficult, with uncertain returns. But new technical, policy and financial opportunities offer hope for rapid progress.
Recent soil tests evaluating “soil health” on a broad scale may not properly consider the intrinsic limitations of soil properties, and have not been assessed in regionally unique soil conditions. To evaluate three soil tests in North Carolina, we used long-term agronomic management trials from three distinct physiographic regions: mountain (22 yr), piedmont (32 yr), and coastal plain (17 yr). Mountain and coastal plain trials included combinations of organic or chemical management with or without tillage; the piedmont trial included nine different tillage treatments. Soil samples were collected and submitted for analysis as recommended by the North Carolina Department of Agriculture and Consumer Services, Haney soil health test (HSHT), and Cornell comprehensive assessment of soil health (CASH). Plant nutrient concentrations varied but were still sufficient for crops. The CASH physical soil indicators, such as surface hardness and aggregate stability, were not statistically different, regardless of tillage intensity or management. Biological soil indicators (e.g., CO2 respiration) responded differently to management, but this differentiation was inconsistent among locations and tests. Despite many years of conservation management, the CASH results described mountain soils as “low” or “very low” soil health for all but no-till organic management, which received a “medium” score. The HSHT results considered soil from all but moldboard plowing (piedmont) to be in good health. Finally, there was no correlation between soil health tests and crop yields from North Carolina soils. Soil health tests should be calibrated to better differentiate among soil management effects that vary depending on intrinsic soil limitations. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
Grazing is one of most important agricultural activities in mountainous and semi-mountainous regions in the Basque Country and a sustainable use, based on soil properties monitorization, is necessary for the conservation of grassland ecosystems. Visible- and near-infrared reflectance spectroscopy (VNIRS) has been reported to be a relevant alternative for monitoring soil properties, given that it rapidly provides a large number of measurements at low cost. The present work aimed at evaluating the feasibility of NIRS to predict usual chemical and biological soil properties. Soil spectra of VNIRS (350–2500 nm) of 147 samples from representative grassland sites of the most common combinations of management practices and altitudes ranges in the Basque Country (Northern Spain) were acquired to predict chemical and biological soil properties (pH, soil organic matter (SOM), total nitrogen (TN), Olsen phosphorus (P Olsen), extractable potassium (K) and basal respiration (BR)). Furthermore, differences were analyzed among a homogenization gradient of soil sample presentations (0–10 cm topsoil fresh core cylinders; fresh and crumbled; and air-dried ground and sieved to ≤ 2 mm) which were respectively acquired with three different probes (contact; sample turn table (STT); muglight). The partial least squares regression (PLSR) method was applied to develop prediction models. With the contact probe and fresh core presentation, the best prediction models were for pH and BR (RPD = 2.67 and RPD = 2.77 respectively; RPD: ratio of prediction to deviation). For fresh samples, spectra recorded with the STT probe provided better prediction accuracy, i.e. RPD = 2.81 and 3.03 for pH and BR respectively. With sample presentation homogenization, calibration models improved for processed samples to a RPD = 3.59 and 3.23 for pH and BR respectively together with SOM (RPD = 4.01). Conversely, P and K were the variables with the poorest models for all cases, with RPD values ≤ 1.82 and ≤ 1.48 respectively. The sample processing effort for soil homogenization related to the used probe improved significantly model quality. Altogether, VNIRS can be considered a useful method for monitoring grasslands soil properties for management purposes.
Crop rotations involving corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] are well-known production systems across the Midwestern United States, but the addition of wheat (Triticum aestivum L.) in the rotation has received less attention. Additionally, the interactive effect of crop rotation with nitrogen (N) fertilizer and foliar fungicide application on yields for these three crops is not yet well understood. Data were collected in Wisconsin from a long-term crop rotation experiment during 2013 to 2015 to measure corn (grain and silage), soybean, and wheat yield response to crop rotation frequency (seven rotations involving corn, soybean, and wheat), six levels of N, and foliar fungicide use. During the 3 yr of the experiment, minimal interactive effects were detected, which suggested that the examined management decisions can remain separate for growers in Wisconsin. Yearly crop rotation of corn and soybean increased corn grain yields in 2014 by 15 to 18% and soybean yields by 24 to 31% in 2015 compared with continuous cropping. No other crop rotation effect was observed. Fungicide use at the V5 growth stage for corn, at R3 for soybean, and at GS9 for wheat, increased wheat (7.4-16.8%) and soybean yield (3.6-5.4%) but not corn grain or silage yields. Nitrogen application was more beneficial for corn compared with wheat and soybean. The effect of N on soybean was similar across all rotations, and grain yields increased when N rate was higher than 100 kg ha⁻¹. The data suggest that N rate recommendations should be based on crop needs, regardless the rotation system. © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved.
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Climate change negotiations at the 21st Conference of the Parties to the United Nations (UN) Framework Convention on Climate Change (COP21) in Paris (November 30 to December 11, 2015) were unique because soil carbon (C) and agriculture were on the agenda for the first time ever since COP meetings started 21 years ago. The “4 per Thousand” proposal calls for a voluntary action plan to enhance soil organic carbon (SOC) content of world soils to a 40 cm (16 in) depth at the rate of 0.4% per year. The strategy is to promote SOC sequestration through adoption of recommended management practices (RMPs) of C farming including conservation agriculture (CA), mulch farming, cover cropping, agroforestry, biochar, improved grazing, and restoration of degraded soils through soil-landscape restoration, etc. Theoretically, the world's cropland soils could sequester as much as 62 t ha⁻¹ (25 tn ac⁻¹) over the next 50 to 75 years (0.8 to 1.2 t ha⁻¹ y⁻¹ [0.3 to 0.5 tn ac⁻¹ yr⁻¹]) with a total C sink capacity of ~88 Gt (~97 billion tn) on 1,400 Mha (3,500 million ac). In addition, there is also SOC sequestration potential of grazing lands, forest lands, and degraded and desertified lands. With global implementation,…
Soil quality is a concept that has deeply divided the soil science community. It has been institutionalized and advocated without full consideration of concept weaknesses and contradictions. Our paper highlights its disfunctional definition, flawed approach to quantification, and failure to integrate simultaneous functions, which often require contradictory soil properties and/or management. While the concept arose from a call to protect the environment and sustain the soil resource, soil quality indexing as implemented may actually impair some soil functions, environmental quality, or other societal priorities. We offer the alternative view that emphasis on known principles of soil management is a better expenditure of limited resources for soil stewardship than developing and deploying subjective indices which fail to integrate across the necessary spectrum of management outcomes. If the soil quality concept is retained, we suggest precisely specifying soil use, not function or capacity, as the criteria for attribute evaluation. Emphasis should be directed toward using available technical information to motivate and educate farmers on management practices that optimize the combined goals of high crop production, low environmental degradation, and a sustained resource.
