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Organic soil amendments influence soil health, yield, and phytochemicals of globe artichoke heads
Abstract
The objective of this study was to assess the influence of plant- and animal-based soil amendments on soil nutrient availability, CO2 respiration, yield and phytochemicals of artichoke (Cynara cardunculus cv. 179) heads. Four certified organic fertilisers: fish meal, blood meal, alfalfa meal and chicken manure, were used as experimental treatments. After two years of organic soil amended with the plant-based fertiliser (alfalfa meal), soil respiration and content of organic matter (OM) was higher than that in soil amended with animal-based fertilisers (fish meal, blood meal, and chicken manure), though the difference in OM between alfalfa and chicken manure was not statistically significant. The marketable yield from soil amended with chicken manure was higher than that amended with alfalfa meal and in the first year (2015) yields from both chicken manure and fish meal treatments were higher than that of the alfalfa treatment. Concentrations of phytochemicals in artichoke heads grown in soil amended with alfalfa treatment were higher than in those grown with animal-based fertilisers (for chlorogenic acid the difference was significant only in 2016). Conversely, the cost of the alfalfa meal was higher than that of the animal-based fertilisers. Overall, plant-based fertiliser can be an ideal option for improving soil and head quality of artichokes, but animal-based fertilisers may be an appropriate choice for organic farmers when yield and cost are the main concerns.
... Also, organic culture proved to suppress soil pathogens, such as Fusarium wilt in cucumber (Cucumis sativus) [144] and plant parasitic nematodes Pratylenchus and Meloidogyne in maize and bean compared to conventional culture systems [145]. [143]; Leskovar and Othman [16]; Othman and Leskovar [147]). For microbial biomass carbon, data were from Chang et al. [146]; Mangalassery et al. [148]; Mäder et al. [137]. ...
... Relative yields differed between crops with soybean, rice, and corn scoring higher than 80% and wheat, barley, and potato scoring lower than 80%. Except for countries with very intensive agricultural systems (e.g., Netherlands where the conventional yield gap was significantly larger), most studied regions had relative [16]; Othman and Leskovar [147]). For microbial biomass carbon, data were from Chang et al. [146]; Mangalassery et al. [148]; Mäder et al. [137]. ...
... Legumes can fix atmospheric N in the soil, reduce the risk of NO 3 − leaching, improve soil physical and chemical properties as well as fruit quality [162,164]. In artichoke, organic soil amended with alfalfa meal had higher soil respiration (soil health indicator) and head phytochemicals than soil amended with animal-based fertilizers (fish meal, blood meal, and chicken manure) [147]. However, artichoke grown in soil amended with animal-based fertilizer (chicken manure) had higher head yield and input cost (N: $US 31 kg −1 for blood meal, $US 28 kg −1 for chicken manure, $US 44 kg −1 for fish meal, and $US 74 kg −1 for alfalfa meal) than those amended using, alfalfa meal [147]. ...
Healthy soil acts as a dynamic living system that delivers multiple ecosystem services, such as sustaining water quality and plant productivity, controlling soil nutrient recycling decomposition, and removing greenhouse gases from the atmosphere. Soil health is closely associated with sustainable agriculture because soil microorganism diversity and activity are the main components of soil health. Agricultural sustainability is defined as the ability of a crop production system to continuously produce food without environmental degradation. Arbuscular mycorrhizal fungi (AMF), cyanobacteria, and beneficial nematodes enhance water use efficiency and nutrient availability to plants, phytohormones production, soil nutrient cycling, and plant resistance to environmental stresses. Farming practices have shown that organic farming and tillage improve soil health by increasing the abundance, diversity, and activity of microorganisms. Conservation tillage can potentially increase grower's profitability by reducing inputs and labor costs as compared to conventional tillage while organic farming might add extra management costs due to high labor demands for weeding and pest control, and for fertilizer inputs (particularly N-based), which typically have less consistent uniformity and stability than synthetic fertilizers. This review will discuss the external factors controlling the abundance of rhizosphere microbiota and the impact of crop management practices on soil health and their role in sustainable crop production.
... In addition, organic manure had positive effects on growth, physiological parameters and also on quality and quantity of essential oil of Agastache foeniculum [4]. Recent studies have shown that organic fertilizer sources (plant-based vs. animal-based) also influence soil health [5]. Organic fertilizer from plant sources, such as alfalfa (Medicago sativa), are an ideal choice for enhancing soil chemical composition and head quality of globe artichokes (Cynara cardunculus). ...
... Organic fertilizer from plant sources, such as alfalfa (Medicago sativa), are an ideal choice for enhancing soil chemical composition and head quality of globe artichokes (Cynara cardunculus). But those from organic animal sources (fish meal and chicken manure) reached a higher yield and net return in sort-term (2 years) compared to plant-based fertilizers [5]. ...
... N, P, K), higher organic matter and lower electrical conductivity. Plantbased fertilizers normally have lower soil electrical conductivity compared to animal-based fertilizers (Table 2) [5,23,35,36]. This is an attribute of the external salt supplement which is normally added to animal diet in order to improve the productivity [37]. ...
The present article reviews the scientific literature
on the influence of organic and conventional
farming as well as organic fertilizer source
(plant-based vs. animal-based) on soil health. Additionally,
the role of tillage practices (conservational
vs. conventional) in soil performance is studied.
Research shows that organic farming systems potentially
enhanced soil health through improved soil
respiration-CO2 (soil health indicator), soil organic
carbon, cation exchange capacity, soil water content
as well as soil microorganism’s (fungi, bacteria and
nematodes) activity and abundance. Conversely,
organic systems had lower yield compared to conventional.
Organic farming sources also significantly
affected soil health. Plant-based fertilizers (e.g.
corn and alfalfa meal) also improved soil health
(respiration-CO2), organic matter %, nutrient availability
and fruit quality. But, animal-based fertilizers
(e.g. fish meal, chicken manure and blood meal)
significantly increased marketable yield compared
to plant-based ones, especially, in short-run projects.
Tillage practices have also an impact on soil
quality variables (physical, chemical and biological
properties). Conservation tillage (no-till and strip)
practices improve soil penetration resistance, organic
carbon, and biota biomass, density, activity and
diversity. In fact, conservation tillage practices
increased soil microorganism (bacteria, fungi and
nematode) activity and abundance and also available
nutrients in comparison to conventional tillage.
However, conservational tillage practices lead to
higher soil compaction and greater number of rootfeeding
nematodes (harmful to plant roots). Overall,
organic farming systems can successfully improve
soil health but may not be the best choice for farmers
whose essential short-term objective is a higher
yield. Also, organic growers with a primary focus
on yield should not use plant-based fertilizers (e.g.
alfalfa).
... Globe artichoke is a popular Mediterranean crop rich in antioxidant compounds such as chlorogenic acid, dicaffeoylquinic acids, and cynarin, which are known to be beneficial for human health [18,19]. In addition to genotype, cultural practices and farming systems have been shown to affect the content of chlorogenic acid, with ranges from 60-600 (µg g −1 ), and cynarin from 2 to 20 (µg g −1 ) [20][21][22][23]. In organic farming, head chlorogenic acid increased by 31% and cynarin by 12% compared to those grown in conventional fields [19]. ...
... Plants produce reactive oxygen species (ROS) in stress conditions (e.g., drought) and to detoxify ROS, the antioxidants and flavonoids play a key role in protecting plants from abnormal abiotic stresses [36,37]. Significant increases in shoot and reproductive growth have been normally coupled with reductions in nutrient and protein concentrations in tissues due to dilution effects [21,23,38]. In this study, this dilution effect was noticed in the content of chlorogenic acid in 2016 (Table 4), where the significant increase (34%) in artichoke yield from the transplanting method produced heads with reduced (54%) chlorogenic acid. ...
The objective of this two-year field study was to assess the influence of stand establishment methods (direct seeding or transplanting) on root growth dynamics, shoot morphology, leaf physiology, yield, and quality of globe artichoke (Cynara cardunculus). Three artichoke cultivars were evaluated, ‘Green Globe Improved’ (GGI), ‘Imperial Star’ (IS), and ‘Romolo’ (ROM). Plants established with the transplanting method had higher mean root length intensity (La), root length, and root surface area as compared to plants established by direct seeding. The topsoil (0–20 cm) had on average higher La, root length, and root surface area than deeper soil profiles. Transplanted
plants had higher plant shoot width and leaf area index (LAI) chlorophyll content index (SPAD) than direct seeded plants at the vegetative stage in 2015. The improvement of root and shoot growth in transplants (compared to direct seeding) also resulted in higher (p < 0.05) marketable yield (21.1 vs. 19.9 ton ha−1 in 2015 and 18.3 vs. 13.7 ton ha−1
in 2016). Additionally, 46–50% of the total yield occurred during the first 30 days of harvest in the transplanting method compared to 13–38% for direct seeding. No significant differences were found between planting methods or cultivars in leaf-level
gas exchange (photosynthesis, stomatal conductance, and transpiration) and cynarin concentration in the marketable heads. Although chlorogenic acid was similar in both establishment methods in 2015, direct seeding had higher concentration in 2016. Comparing cultivars, GGI had higher root length, surface area, root volume, and earlier and higher marketable yield than ROM. However, ROM had higher mean root length intensity (La; total root length per specific area in soil profile) than GGI in both growing seasons. This study showed significant and consistent improvements in root and shoot traits, and yield for transplants as compared to direct seeded plants.
... Sauerbeck (1982) revealed that the accumulation of SOC increased in the order of green manure < straw < fresh manure < composted manure. Othman and Leskovar (2018) showed that soil respiration and SOM contents were enhanced with applications of plant-based fertilizers such as alfalfa (Medicago sativa L.), compared with animal-based fertilizers including fish meal, blood meal, and chicken manure. However, application of chicken manure and fish meal resulted in higher artichoke yields compared with application of alfalfa (Othman & Leskovar, 2018). ...
... Othman and Leskovar (2018) showed that soil respiration and SOM contents were enhanced with applications of plant-based fertilizers such as alfalfa (Medicago sativa L.), compared with animal-based fertilizers including fish meal, blood meal, and chicken manure. However, application of chicken manure and fish meal resulted in higher artichoke yields compared with application of alfalfa (Othman & Leskovar, 2018). As such, knowledge of the characteristics and properties of organic amendments is essential when ...
The objectives of this study are to compare the chemical properties of organic matter (OM) in alkaline extracts of turkey litter compost, source‐separated organic compost, and biosolid pellets, and to validate the use of humic acids (HAs) for analyzing the functionality (i.e., the ability to complex with nutrients) of OM. The humic fractions, including (HAs), fulvic acids (FAs), and alkaline nondissolved fraction (humin), were isolated either with NaOH or Na4P2O7 (PyroP) and the chemical properties were analyzed by solid‐state ¹³C NMR spectroscopy. The study showed that the proportions of each functional group of the combination of HAs, FAs, and humin were essentially identical to that of their HCl‐treated original materials, except for a lower recovery of O‐alkyl groups. Although the yield of HAs extracted with PyroP was lower than that with NaOH, their spectral characteristics were not significantly different. The functionality of the OM, assuming a correlation with the sum of the proportions of carboxyl and phenolic groups, was higher in both HAs and FAs than that in humin. Based on the proportion and functionality of the HAs in the OM, we conclude that the use of HAs extracted with either NaOH or PyroP is valid for studies of OM functionality. The study also shows that the functionality and stability of OM are highly source dependent. We predict that amendments of the more humified turkey litter compost would have higher potential to increase SOM levels and retain nutrients compared with the source‐separated organic compost and biosolid pellets.
... Agricultural interventions have, however, frequently changed this. Most of the internal processes of the agricultural soil system, which is a subsystem of the agro-ecosystem, interact in different ways at different geographical and temporal scales [39]. Biological fertilisers, composts, ground coverings, mulches, and biological ...
A healthy soil serves as a dynamic living system that provides a variety of ecosystem services, including maintaining plant production, managing the recycling and breakdown of soil nutrients, and eliminating greenhouse gases from the environment. Because soil microbial activity and variety are the primary determinants of soil health, soil health and sustainable agriculture are intimately related. Tillage and organic farming have been demonstrated to enhance soil health by raising the quantity, variety, and activity of microorganisms in the soil. While organic farming may result in exclusion of synthetic fertiliser inputs, and improve stability in environment sustainability, conservation tillage has the potential to increase growers' profitability by reducing inputs and labour costs when compared to conventional tillage. The capacity of a crop production system to consistently generate food without causing environmental damage is known as agricultural sustainability. Beneficial microbes, nematodes, cyanobacteria, and arbuscular mycorrhizal fungus (AMF) improve plant water and nutrient availability, phytohormone synthesis, soil nutrient cycling, and plant resilience to environmental challenges. Concepts related to soil health are frequently used to compare soils, analyse changes, and gauge how well land-use management is working. The external elements influencing soil health and their significance for sustainable agriculture will be covered in this review.
... A two-year study compared the influence of plant-and animal-based organic fertilizers on soil nutrient availability, yield, and phytochemical content of artichokes. It was found that the concentration of phytochemicals was higher in soil treated with alfalfa meal than in those treated with animal-based fertilizers [136]. Given the higher cost of alfalfa meal, the authors concluded that while plant-based fertilizers might be ideal for improving soil and the quality of artichoke heads, animal-based fertilizers might be a more suitable choice for organic farmers when yield and cost are primary considerations. ...
Organic farming, which is deeply rooted in traditional agricultural practices, has witnessed a profound evolution over the last century. Transitioning from a grassroots initiative resisting the industrialization of agriculture to a global industry, organic farming now plays a pivotal role in addressing contemporary challenges related to environmental health, sustainability, and food safety. Despite the growing consumer demand for organic products and market access, organic farming has its challenges. This paper discusses the origin and evolution of organic farming with an emphasis on different types of organic fertilizers, benefits, and challenges. Nutrient variability and the slow-release nature of organic fertilizer often do not meet crop demands and can substantially reduce yield. Some organic fertilizers, like manure and biosolids, can provide a higher yield benefit, but there are environmental and health risks associated with them. Weed and pest management in organic farming can be labor-intensive and increase costs. Inefficient planning of organic farming and rapid transition can also create food insecurity. This paper also gives a brief account of the current certification process for organic fertilizers and their technicalities. It showcases how the holistic approach of organic farming extends beyond production, including strategies like reducing food waste and building self-sufficient farming communities. These practices contribute to a more sustainable agricultural system, reducing environmental impacts and supporting local economies. Future technological innovations, especially in precision agriculture and bio-physicochemical models, can help in formulating targeted organic fertilizers.
... Specifically, to artichoke, to our knowledge, just a few research projects compared the chemical composition of organic artichoke heads versus conventional ones. Additionally, there is no study regarding the comparison of the respiratory activity, texture properties, fibre and sugar content of the heads (Spanu et al., 2018;Leskovar and Othman, 2018;Othman and Leskovar, 2018;Yildirim et al., 2020). Yet, results related to comparison between organic and conventional grown artichoke are contrasting according to the cultivar taken into consideration. ...
... Cantaloupe is a commercially important crop in many countries, being cultivated in all temperate regions of the world in part due to its good adaptation to soil and climate. Cantaloupe is an extremely fragile commodity; even if harvested, managed, and held under ideal conditions, the fruit will retain good quality for only about two weeks after the harvest [9] . ...
Biostimulants are biological additives that are used in crop production to improve plant growth, productivity, and health. This research aimed to study the effects of cantaloupe (Cucumis melo L.) production in organic management systems influenced by humic substances and biochar. The study was conducted in replicated research trials conducted during the 2020 to 2021 growing seasons at the Tennessee State University Organic Research Farm (TN, USA). Two organic varieties, Divergent F1 and PMR Delicious 51 were selected for the study. Three treatments included 1) humic substances, 2) fulvic acid and humic acid combination, and 3) biochar. The parameters examined were number of fruits, fruit height, fruit diameter, and fruit weight through comparisons within each variety and between two varieties. Results indicated significant variations in fruit height and fruit diameter but not in fruit weight between two varieties. Within var. PMR Delicious 51, there were significant distinctions in fruit height, fruit diameter and fruit weight for the humic substances’ treatments (HA and HA + FA) compared to biochar and control. Biochar treatment showed improved yield traits in the 2020 research trial, however humic substance combination concluded exceptional plant growth and yield in the 2021 trial. Humic substances combined and alone yielded more fruits per plant in both research trials. Significant variance in fruits per plant was recorded in var. Divergent F1 in humic substance combination which generated higher yield. Fruit diameter and fruit weight in cantaloupe treated with humic substances were higher compared to biochar in the 2021 research trial. Humic acids were observed to be effective at improving yields of var. Divergent F1 within the two research trials conducted.
... To ensure consistency in soil sampling horizons and periods, soil cores (4 cores per zone, from 0-30 cm depth) were collected, sieved in a 2 mm sieve, and transferred in ice box into laboratory from the four reserves. Soil respiration was measured using the Solvita Soil Respiration System (Solvita) [18]. The test was determined on 40 g air dried soil. ...
Healthy forests are essential to human life because they provide food, energy, and other benefits including carbon sequestration. The objective of this study was to assess the forests health status in Mediterranean ecosystems, specifically, arid to semi-arid. Four forest reserves directed by Royal Society for the Conservation of Nature, Jordan were evaluated. Plant health indicators [(gas exchange (photosynthesis, stomatal conductance, transpiration), chlorophyll, middy stem water potential (Ψsmd), relative water content], regeneration, lichens, plant disease, as well as soil variables (respiration CO2-C, electrical conductivity (EC), pH, microorganisms' abundance) were measured. The Ψsmd values in those semi-arid/arid ecosystems were within the normal ranges (−0.3 to −1.3 MPa) in spring but was under extreme water stress (−1.6 to −5.3 MPa) in summer in three reserves. Similarly, gas exchange variables reduced by 25%-90% in summer (compared to spring) across the studied forests. Although the regeneration (seedling per 1000 m 2) was higher than 100 in two forest (Ajloun and Dibbeen), the number of seedlings in hiking sites was extremely low in both forests. Soil health indicators reveled that soil respiration CO2-C were higher than 25 mg kg −1 in two forests [Ajloun, Dibbeen, (except hiking zone)]. The mean soil saprophytes (number g −1) ranged from 86 to 377 across the forests reserves. In addition, the mean arbuscular mycorrhizal fungi (spores 100g −1 soil) was between 350 and 877. Soil EC was consistently optimal (less than 0.5 dS m −1) and pH was slightly basic (7.5-8.3) across the reserves. The results revealed that the fluctuation of rainfall and anthropogenic pressures (grazing, hiking) led to partial forest degradation. When forests (Dana Bi-osphere Reserve) received 81 mm annual precipitation, Ψsmd values in Juniperus phoenicea at summer ranged from −4.4 to −5.3 MPa, regeneration and lichens were less than 20 per 1000 m 2 , and several trees were dead after infected with soil and air borne pathogens including wilt diseases and die back. Intensive hiking activities (Dibbeen forests, tourism area) and heavy grazing (Yarmouk frosts) reduced regeneration, lichens and soil respiration. Interestingly, the native species had better water relations (RWC, Ψsmd) and gas exchange performance than the introduced species. Overall, it is better to grow native species, and exclude anthropogenic pressure on the territory of introduced species. The conservation programs must persist to sustain several native historical forest trees including Juniperus phoenicea (>600 year old), Quercus ithaburensis (>500 year old), and Pinus halepensis (>100 year old) at Mediterranean semi-arid forests. Citation: Alananbeh, K.M.; Othman, Y.A.; Tahat, M.M.; Al-Dakil, H.; Yahya, A.A.; Ayasrah, B.; Al-Share, T.; Alkhatatbeh, S.; Al-Zoubi, R.; Alnaanah, M.; et al. Forests Health Assessment in Four Jordanian Reserves Located in Semi-Arid Environments. Forests 2023, 14, 918.
... Soil respiration has been used as an indicator for soil health by measuring the CO 2 emission that resulted from the respiration of soil micro-organisms [60]. Respiration gives a reliable and scientific basis on which to evaluate microbial activity [61]. ...
Lawns achieve environmental, functional, and aesthetical roles in urban environments. The objectives of this research were to assess the effect of different salinity levels on Trichoderma isolates and to study the effect of Trichoderma spp. on perennial ryegrass under different levels of salinity. T. harzianum (ThLem2017-01) and T. atroviride (TaDP2019-01) isolates had a higher mycelium growth rate than T. atroviride (TaDP2019-02) when salinity levels were low. In contrast, the mycelium growth rate of T. atroviride (TaDP2019-02) isolate at high salinity levels had superior results. Turfgrass seeds that were inoculated with (TaDP2019-02) isolate maintained high radicle length, coleoptile length, and leaf length under high salinity levels. Increasing salinity level decreased clippings’ fresh weight (FW), dry weight (DW), and shoot and root dry weight of perennial ryegrass. Interestingly, perennial ryegrass pots that were treated with (TaDP2019-02) isolate had increased FW and DW by 16 to 114% and 24 to 76%, respectively. Soils that were inoculated with Trichoderma (TaDP2019-02) had higher CO2 respiration (75%) than the control. Therefore, using T. atroviride (TaDP2019-02) isolate revealed promising results in increasing plant biomass and as an environmentally friendly alternative factor to overcome salinity stress.
... Plants are also effective against several organic contaminants and, thus, can be used to remediate organic pollutants (Rada et al., 2019;Donati et al., 2019;Ahmad et al., 2017;Cole, 1998). The use of plants in bioremediation processes has several benefits such as lower cost, possible recovery and reuse of metals, maintains the fertility of soil (Ali et al., 2013), helps to increase the health of soil, yield, plant phytochemical (Othman and Leskovar, 2018), reduces leaching of metals and erosion of soils (Ali et al., 2013), but the processes also have some limitations. There are various processes mediated by plants in the treatment of environmental issues, such as phytoextraction or phytoaccumulation or phytosequestration (phytoextraction exploits the capability of plants or algae to eliminate pollutants from soil or water by converting them into harvestable plant biomass. ...
Biofilm is an aggregate of microorganisms enclosed inside an extracellular polymeric substance (EPS) matrix adhering to living or non-living surface. It has extensively been studied since it was identified as the primary growth mode of microbial life. As biofilms are extremely resistant to antimicrobials in the clinical set-ups and food processing industries, they have been considered a threat to human health. On the other hand, biofilms also have beneficial properties and they can be exploited due to their suitability for the remediation of pollutants. Biofilms have been proved appropriate for pollutants remediation due to their high microbial biomass and pollutants immobilization capability. It has the ability of treating wastewaters having certain types of contaminants. In this chapter, we will discuss the role of the biofilms in pollutants remediation from the environment. Attention should be given to hydrocarbons, pharmaceuticals, halogenated compounds, toxic chemicals, pesticides and some heavy metals, as these groups signify the majority of significant pollutants. The biofilm structure and durability along with the varied range of metabolic and structural features make such communities striking performers in ecosystems monitoring and also in biofilm-enabled remediation solutions.
... Plants are also effective against several organic contaminants and, thus, can be used to remediate organic pollutants (Rada et al., 2019;Donati et al., 2019;Ahmad et al., 2017;Cole, 1998). The use of plants in bioremediation processes has several benefits such as lower cost, possible recovery and reuse of metals, maintains the fertility of soil (Ali et al., 2013), helps to increase the health of soil, yield, plant phytochemical (Othman and Leskovar, 2018), reduces leaching of metals and erosion of soils (Ali et al., 2013), but the processes also have some limitations. There are various processes mediated by plants in the treatment of environmental issues, such as phytoextraction or phytoaccumulation or phytosequestration (phytoextraction exploits the capability of plants or algae to eliminate pollutants from soil or water by converting them into harvestable plant biomass. ...
Dyes are highly coloured compounds being extensively used by different types of industries for dyeing various materials. They are highly useful in dyeing clothes, papers, fibres, leathers, food materials, boards, woods, etc. There are various types of dyes, but broadly, they may be divided into natural and synthetic dyes, out of which most of the dyes are synthetic, derived from petrochemicals. These dyes or by-products released into the aqueous environment are highly toxic to the living beings in that environment as well as to human beings. Dyes act as big pollutants as they are released in wastewater and cause significant harms to biological systems. Most of the synthetic dyes are carcinogenic, while many of them are also not easily degradable. Pollutions caused by synthetic dyes are a matter of serious concern in the modern time due to their indiscriminate use. Poor safety measurements as well as poor pollution control techniques are also responsible for this. In the present time, several researches are going on the development of techniques and methodologies for the treatment of various toxic dyes and dye accumulations, out of which biological research attracts significant attention due to its green methodologies. Detoxification of dyes using microbes, enzymes, plants or any biological sources by applying green techniques are generally known as bioremediation of dyes. Plants, individually or as in combination with microbes, may play a good role in the detoxification of dyes. This chapter nicely deals with the significances of plants in bioremediation of synthetic dyes either individually or in combination with other biological resources.
... In the last decade, several organic fertilizers are available commercially such as, plantbased (e.g., leguminous crop) and animal-based (e.g., blood and fish meals, feathers, bones and composted-manure) fertilizers (Gaskell and Smith, 2007;Othman and Leskovar, 2018). Legumes green manure improve soil physical and chemical properties, improves soil N fertility and reduce the risk of nitrate (NO3) leaching (Fauci and Dick, 1994;Vyn et al., 2000;Fageria, 2007). ...
Organic farming systems contribute to enhance food security and agricultural sustainability. with the potential to increase farmer’s income when external input costs are reduced. Two experiments were conducted to evaluate the influence of organic farming on soil quality (respiration-CO2), yield and head quality (chlorogenic acid and
cynarin concentration) of globe artichoke (Cynara cardunculus). Both experiments were conducted over two growing seasons, October 2014 to June 2016. In the first experiment, we compared organic and conventional farming systems while organic matter fertilizer source (plant- vs. animal-based) evaluation was considered in the
second experiment. For the first experiment, eight cultivars were used; ‘Deserto’, ‘Lulu’, ‘Romolo’, ‘11-018’, ‘12-179’, ‘Green Globe Improved’ and ‘Imperial Star’. The cultivar ‘12-179’ was used for the second study in order to screen plant-based (alfalfa meal) and
animal-based (fish meal, blood meal, and chicken manure) fertilizers for soil health, yield and head quality. Conventional farming had higher plant marketable yield compared to organic. Conversely, artichoke head from organic farming had 31% chlorogenic acid and 12% cynarin higher than conventional system. Interestingly, organic farming improved the soil health indicator (respiration-CO2) by 20-fold
compared to conventional. Although cultivar response to soil farming system treatments was inconsistent across the study period (2015-2016), ‘Imperial Star’ had the lowest marketable yield and head quality. After two years of organic soil amended with animal-based fertilizers, marketable yield was higher than soil amended with plant-based fertilizer. However, alfalfa meal (plant-based) organic fertilizer increased soil respiration by about 3.5-fold compared to animal-based (fish meal, blood meal, and chicken manure) organic fertilizers at the end of the experiment. In addition, concentrations of phytochemicals (chlorogenic acid and cynarin) in artichoke heads grown in soil amended with alfalfa meal were higher than in those grown with animal based fertilizers.
... This is because external salt is normally added to animal diet to increase productivity and prevent mineral disorders (Diacono and Montemurro, 2015). Therefore, it is highly probable that organic fertilizer sources will significantly impact soil chemical properties as recently reported for animal-based (fish meal, blood meal, and chicken manure) or plant-based (alfalfa meal) fertilizers (Othman and Leskovar, 2018). ...
Soil amendment using organic fertilizer has been used widely to dispose animal waste, reduce environmental pollution and improve soil and fruit quality. The objective of this two-year study was to assess the influence of organic and conventional systems on growth, marketable yield, head quality (chlorogenic acid and cynarin concentration) and soil chemical properties of globe artichoke (Cynara cardunculus). Cultivars used were Deserto, Lulu, Romolo, 11-018, 12-179, Green Globe Improved and Imperial Star. Fertilizers were applied to both conventional and organic soil through drip irrigation system. In both years, significant differences were found across cultivars and soil type. Although cultivar response to soil system treatments were inconsistent across the two growing seasons, the cv. Imperial Star had the lowest marketable yield and head quality. Artichoke grown in the conventional field had higher plant height and width, chlorophyll content index (SPAD), leaf area index (LAI), stomatal conductance (gs), photosynthesis (Pn) and marketable yield. Conversely, artichoke head quality from the organic field was higher than conventional. Organic system increased chlorogenic acid by 31% and cynarin by 12% compared to the conventional system. In fact, after two years of soil amendment, organic fertilizer improved soil respiration-CO2 (soil health indicator) by 20-fold compared to chemical fertilizer (conventional field). Overall, based on this two-year study we suggest organic farming as the best system to improve soil and head quality of globe artichoke, but it may not be the best option for farmers when yield is the primary target short-term.
... This is because external salt is normally added to animal diet to increase productivity and prevent mineral disorders (Diacono and Montemurro, 2015). Therefore, it is highly probable that organic fertilizer sources will significantly impact soil chemical properties as recently reported for animal-based (fish meal, blood meal, and chicken manure) or plant-based (alfalfa meal) fertilizers (Othman and Leskovar, 2018). ...
Soil amendment using organic fertilizer has been used widely to dispose animal waste, reduce environmental pollution and improve soil and fruit quality. The objective of this two-year study was to assess the influence of organic and conventional systems on growth, marketable yield, head quality (chlorogenic acid and cynarin concentration) and soil chemical properties of globe artichoke (Cynara cardunculus). Cultivars used were Deserto, Lulu, Romolo, 11-018, 12-179, Green Globe Improved and Imperial Star. Fertilizers were applied to both conventional and organic soil through drip irrigation system. In both years, significant differences were found across cultivars and soil type. Although cultivar response to soil system treatments were inconsistent across the two growing seasons, the cv. Imperial Star had the lowest marketable yield and head quality. Artichoke grown in the conventional field had higher plant height and width, chlorophyll content index (SPAD), leaf area index (LAI), stomatal conductance (gs), photosynthesis (Pn) and marketable yield. Conversely, artichoke head quality from the organic field was higher than conventional. Organic system increased chlorogenic acid by 31% and cynarin by 12% compared to the conventional system. In fact, after two years of soil amendment, organic fertilizer improved soil respiration-CO2 (soil health indicator) by 20-fold compared to chemical fertilizer (conventional field). Overall, based on this two-year study we suggest organic farming as the best system to improve soil and head quality of globe artichoke, but it may not be the best option for farmers when yield is the primary target short-term.
This review addresses the growth and development of medicinal plants under arid land conditions and the potential use of remote sensing technologies to map their distribution, as well as morphological and physiological responses in Arid lands. Plant morpho-physiological variables including, chlorophyll content, and gas exchange (photosynthesis, transpiration, vapor pressure, and stomatal conductance) are linked to plant water status. Multispectral and hyperspectral remote sensing techniques are promising for detecting morphological physiological changes. Vegetation indices derived from hyperspectral
and multispectral imagery makes it possible to assess medicinal plants’ health through successful detection of the ground plant physiological variables and canopy cover including chlorophyll, canopy density, gas exchange (red, 600-700 nm, nearinfrared spectrum, 700-1100 nm) as well as water status (shortwave infrared, 1300-2500 nm). Surface reflectance data within the shortwave infrared bands (water bands) revealed significant differences between well-watered and drought-stressed plants. However, the moderate spatial resolution (Sentinel-2: 20 m, Landsat: 30 m) for the space-born free sensors and the need for a cloud-free sky could be limitations. Overall, vegetation indices derived from remotely sensed data are a useful approach for estimating the physiology of plants (medicinal plants) especially those under drought stress.
Applications of gibberellic acid (GA3) during the vegetative stage is used routinely in artichoke production systems in semi-arid regions to induce vernalization and improve yield. The objective of this two-year field study was to evaluate the effect of exogenous GA3 (20 mg l⁻¹) application date (4th and 8th leaf stages) and frequency (two and three times) on morphological and physiological traits, yield and head quality of globe artichoke (Cynara cardunculus L. cv. Green Globe Improved) under a warm and semi-arid environment. Foliar application of GA3 at the 4-leaf stage increased plant height across growing seasons. However, no significant differences between application dates were noticed in plant width, gas exchange and leaf area index when measured at the harvesting period. GA3 application frequency (two or three) did not affect yield and head quality. Interestingly, foliar application of GA3 at 8-leaf stage increased yield by 13%, chlorogenic acid by 19%, cynarin by 30% and total N by 20% compared to the application at 4-leaf stage. In both years, GA3 applied at 8-leaf stage delayed the harvesting by 10 days when compared to plants that received GA3 application at 4-leaf stage. Considering the increase in yield and head quality without negative effects in canopy morphology or leaf physiology two applications of GA3 at the 8-leaf stage appears an effective crop management strategy for globe artichoke grown under warm climates.
Polyethylene mulch is widely used for vegetable production in the United States as a tool to conserve water, control weeds, and produce earlier and cleaner products (i.e., less attached soil). However, the increasing labor costs for mulch removal and disposal after harvest and soil environmental pollution are major concerns. The objective of this study was to assess fruit yield and quality, mulch deterioration, soil microbial activity, and nutrient changes in 'Stargazer' watermelon (Citrullus lanatus) grown with degradable plastic mulch. The deterioration rates of degradable mulch were 7%, 37%, 57%, and 92% after 120, 210, 300, and 365 days, respectively, of placing the mulch in the field. However, the extra difference in using degradable mulch was calculated as 600.9/acre vs. degradable $659.5/acre), including all costs associated with laying and disposing. One year after placing mulch in the field, the nitrate content and total and active fungi numerically increased (P = 0.08) in soils with the degradable mulch compared with polyethylene mulch. However, there were no statistical differences in soil phosphorus, potassium, organic carbon, and total and active bacteria. Extra-large fruit size yield (category >24.0 lb) from the polyethylene mulch treatment was higher than that from degradable mulch, whereas the 18.0-to 24.0-lb category was lower than that with degradable mulch. However, total yield and total soluble solids from both mulches were statistically similar. Considering the complete deterioration (less waste), mulch removal cost (not required), microbial associations (higher fungi abundance and activity), and similar yield and fruit quality of degradable mulch compared with polyethylene, the implementation of degradable mulches in commercial watermelon field practices is promising.
Plants and microbes are the reservoirs of many structural and biological distinctive properties, which can be used to combat against environmental pollutants. They are the primary producers of ecosystems and transfer the primary productivity in the form of carbon energy to higher trophic levels in the food chain. They play a pivotal role in protecting the environment by reducing greenhouse gas emission, excess nutrients, heavy metal degradation, and other pollutants. They are found in every kind of habitat such as terrestrial, aquatic, and desert. A direct correlation has been identified among different plant and microbial communities, at different pollution levels, and different heavy metals in their habitats. Besides this, species composition of plants and microbes depends on different types of habitats and abiotic environmental factors. They consume excess amount of nutrients from the land and wastewater and take up CO2 from the environment by the process of photosynthesis maintain the biological oxygen demand (BOD) and chemical oxygen demand (COD) of the habitat and restore the original conditions of natural habitat by reducing environmental and soil pollution. Further, their biomass can be used for bioenergy production, food production, and novel biochemical production for human and animal welfare. Further, their residual part can be utilized as fodder to cattle. The main aim of the article is to overview the advances in current and futuristic techniques for phytoremediation.
The objective of this two-year study was to assess the influence of using a leguminous crop, Sesbania grandiflora, on soil nutrient levels (NO3, P, K, Ca2+, Mg2+, Na and S), pH, EC, soil organic matter (OM) and respiration. Sesbania seeds were planted in a certified organic field in March at a planting density of 50 kg ha-1 in 2015 and 90 kg
ha-1 in 2016. In order to determine soil chemical analysis, soil cores were collected from the topsoil layer (0-20 cm) prior to the experimental period in February, 2015, and from 3 soil depths (0-20, 20-40 and 40-60 cm) at the end of 2015 and 2016 growing
seasons. Except for soil OM %, soil nutrients (NO3, P, K, Ca2+, Mg2+, and S) and pH were higher in 2015 than 2016. In both years soil P, K, Mg2+, OM% and respiration in the topsoil layer (0-20 cm) was higher than at deeper soil depths (20-40 and 40-60 cm). Conversely, soil Ca2+, S, and Na in the 40-60 cm soil layer were higher than in the topsoil (0-20 cm). No significant differences were found in soil pH, EC and NO3 across soil layers during the study. Additionally, shoot NO3 and total N concentration during the flowering period was similar across both years. Shoot NO3 was 415 and 425 ppm, and total N was
2.98 and 3.06%, in 2015 and 2016, respectively. Interestingly, soil respiration in the topsoil (0-20 cm) increased slightly in 2015, but by 9-fold in 2016 as compared to the baseline level measured in February, 2015. In addition, soil respiration in the 20-40 cm and 40-60 soil depth was 39 and 50% lower than the topsoil (0-20 cm) at the end of the
experiment in July 2016. Overall, this study revealed that organic soil amendment using Sesbania grandiflora significantly improved soil respiration, but did not potentially enhanced nutrient levels compared to the baseline soil.
This research was aimed at assessing the impact of different doses of nutrients on growth and flower quality of the Asiatic hybrid Lilium ((Lilium × elegans Thunb.) cv. ‘Fangio’) under the soilless culture. Five nutrient (fertigation) regimes were applied (T1: daily, T2: twice a week, T3: weekly, T4: twice a month and T5: control). Increasing the nutrient supply increased chlorophyll content index (SPAD, 45–93%), leaf area (30–55%), number of flowers per plant (25–67%) and substrate electrical conductivity (EC: 28–300%) compared to control. Although T3 (weekly nutrient supply) had lower shoot N, P, K+ and Ca+2 concentrations than T1, this regimen increased the number of flower buds by 20% and flower longevity by 56% compared to T1. Overall, weekly nutrient application is effective at maintaining flower quality and yield in the ‘Fangio’ lily, and compares favourably with programs in which fertigation is more frequent and the level of total applied nutrients is higher.
Nitrogen (N) mineralisation contributes considerably to crop growth in fertilized and unfertilized fields. It is useful to be able to assess potential N mineralisation to increase fertilizer application efficiency, prevent excessive N runoff, and improve environmental system models. The microbes present in soil mineralize N based on many factors, including soil temperature and moisture, tillage, and levels of organic C and N. The measurement of soil’s ability to mineralize N is considered a good indicator of soil quality. Many methods have been developed to estimate N mineralisation in the laboratory and field. The 7-day anaerobic N mineralisation method developed in the 1960’s is considered reliable and is often used to compare new N-mineralisation testing methods. This study examines the use of soil CO2 evolution as determined using the Solvita Soil Respiration System (Solvita) for estimating N mineralisation by comparing it directly to the anaerobic N mineralisation test. Measured CO2 using Solvita was strongly correlated with anaerobic N mineralisation (r 2 = 0.82). Results indicate that the Solvita Soil Respiration System can be used to rapidly assess soil respiration and relative N mineralisation potential in any given soil and is considerably faster and easier to perform in a laboratory setting than the anaerobic N mineralisation test.
Demand for New Mexico’s limited water resources coupled with periodic drought has increased the necessity for tree water status monitoring to guide irrigation scheduling of pecan (Carya illinoinensis) orchards. The objectives of this study were to assess the impact of water status developed during the flood irrigation dry-down cycles on photosynthesis (Pn), and gas exchange [stomatal conductance (gS) to H2O (gH2O), transpiration (E), and intercellular CO2 (ci)] and to establish values of midday stem water potential (Ψsmd) that are needed to maintain Pn and gas exchange of pecan. We conducted the study simultaneously on two southern New Mexico mature pecan orchards from 2011 through 2013. Flood irrigation as determined by grower practice was used on both orchards and Pn, gH2O, E, and ci were assessed at Ψsmd of –0.4 to –2.0 MPa. Photosynthesis and gas exchange were higher in pecan trees shortly after irrigation than trees exhibiting water deficit near the end of a flood irrigation dry-down cycle. The decline in Pn was markedly noticeable when Ψsmd dropped below –0.9 MPa. We attributed the reduction in Pn mostly to stomatal limitation. The decline in Pn and gH2O exceeded 50% when Ψsmdranged from –1.5 to –2.0 MPa. For those reasons, we recommended that pecan orchards be maintained at Ψsmd higher than –0.90 MPa to prevent significant reductions in carbon assimilation and gas exchange. © 2014 by the American Society for Horticultural Science.All rights reserved.
Studies of the effect of organic fertilization of perennial crops are scarce due to the time necessary for the plants to present the first results. The objective of this study was to assess the leaf nitrogen (N) content, the direct and indirect measures of chlorophyll content, fruit yield and their correlations in an orchard of adult guava trees of the Paluma cultivar, through five consecutive harvests, in function of application of a byproduct of guava processing. The following doses of the byproduct were applied: 0, 9, 18, 27 and 36 t ha−1. The material was applied on the surface, without incorporation, once a year between 2006 and 2010. The byproduct doses influenced the nitrogen concentrations, SPAD index, chlorophyll b level and fruit production.
To explore the effects of long-term organic and mineral fertilization practices on the physical properties in Ultisol of south China, a study was conducted since 1998 to investigate the effects of a control (CK), application of chemical fertilizers (NPK), application of organic manure (OM), and NPK fertilizer plus straw returning (NPK + straw). Results showed that OM significantly increased soil water retention capacity at all tensions but with larger increment in low tension at depths of 0–10 cm and 10–20 cm (p < 0.05) when compared with the CK. On the contrary, NPK and NPK + straw led to a decrease in soil water retention capacity under chemical treatments. In the field both in wet and dry periods, soil water content was significantly higher in OM than in NPK + straw and NPK (p < 0.05) since soil hydraulic conductivity (saturated and unsaturated) are lower in OM than in other treatments (p < 0.05). OM was also found to have the lowest soil bulk density and penetration resistance of the four treatments. A high negative correlation was observed between the soil organic carbon and the bulk density and the penetration resistance (p < 0.01). In this way, the application of OM improved the clayey soil physical properties.
The impact of organic fertilizer source on the growth, fruit quality, and yield of blackberry (Rubus L. subgenus Rubus Watson) cultivars (Marion and Black Diamond) grown in a machine-harvested, organic production system for the processed market was evaluated from 2011 to 2013. The planting was established in Spring 2010 using approved practices for organic production and was certified in 2012. Plants were irrigated using a dripline under a woven polyethylene groundcover (weed mat) installed for weed management. Two sources of liquid fertilizer were evaluated: 1) a corn steep liquor and fish waste digestion blend ("corn"; 2.5N-1.1P-1.2K); and 2) a fish solubles and molasses blend ("fish"; 4N-0P-1.7K). Fertilizers were applied by fertigation through the drip system at rates of 56 kg.ha(-1) nitrogen (N) per year in 2011-12 and 90 kg.ha(-1) N in 2013. The impact of fertigation on drip system performance was evaluated with two maintenance options, "flushing" and "no flushing" of the driplines. Total yield differed among years, whereas fruit soluble solids concentration and firmness as well as floricane biomass at pruning showed a year x cultivar interaction. 'Black Diamond' had greater total yield and average fruit weight than 'Marion', but produced a greater proportion unmarketable fruit. There was no effect of fertilizer source on yield, fruit quality, primocane length, or primocanes/plant in any year with the exception of fruit weight, which was greater with corn than with fish. 'Marion' had a greater floricane biomass when fertilized with fish than with corn. Soil nutrients were within the recommended range, except for boron (B), which was below recommended levels. Only soil nitrate-N was affected by fertilizer source, which was greater in 'Marion' than in 'Black Diamond' when fertilized with fish. Primocane leaf tissue nutrient concentrations were within recommended levels for all nutrients, except for calcium (Ca) and B, which were below recommended standards in both cultivars. Primocane leaf potassium (K) and zinc (Zn) concentrations were greater with fish than with corn. There was no fertilizer source or maintenance effect on emitter flow rate of the drip system in either year. However, flow rates decreased an average of 4.5% in the first year and 19% in the second year. Overall, there were no differences between the fertilizers on plant growth, yield, or fruit quality, and both fertilizers were suitable for planting establishment.
An inadequate replacement of organic matter in agricultural lands progressively leads to soil fertility reduction and therefore, soil application of organic fertilizers and amendments should be promoted. The objectives of this 3-year research project on organic lettuce were to investigate the agronomic performance of experimental organic amendments obtained by using agro-industrial wastes in comparison with a commercial organic fertilizer, and to evaluate their short-term effects on soil mineral-N and soil organic carbon changes. Two types of olive pomace mixtures, with different initial C/N ratios, were composted and either stopped at the active phase (A1 and B1) or processed until maturation (A2 and B2). Also an anaerobic digestate (DA) and the B2 in combination with mineral fertilizer (B2-MIN) were studied. The four composts, DA and B2-MIN were compared with a commercial organic fertilizer (Org), and an unfertilized control (N0). Results suggested that the best compromise for organic lettuce yield and soil fertility could be obtained with the B2 compost, thus highlighting the need for choosing a good stage of maturity of the compost, along with an appropriate C/N ratio of composting mixture, to improve the fertilizing efficiency of agro-food residues in organic farming. Furthermore, the application of immature amendments did not increase (B1) or significantly reduce (A1) marketable lettuce yield, indicating that the choice of organic fertilizer is an important concern in sustainable agriculture, especially in organic vegetable production
Globe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] has been recently introduced as a specialty crop in southwest Texas. Marketable yield, yield components, quality, and phenolic compounds of artichoke heads were investigated in response to three irrigation [50%, 75%, and 100% crop evapotranspiration (ETc)] regimes and four nitrogen (0 to 10, 60, 120, and 180 kg ha-1) rates under subsurface drip irrigation. Field experiments were conducted over three seasons (2005-2006, 2006-2007, and 2007-2008) at Uvalde, TX. Irrigation was more effective than nitrogen (N) rates to optimize crop yield and head quality. Marketable yields significantly increased at 100% ETc compared with 75% and 50% ETc, whereas a 20% to 35% yield reduction occurred at 50% ETc across seasons. This yield reduction was associated with a decrease in both number of marketable heads and head weight and with reductions in plant physiological responses as measured in the last season. The lack of yield responses to N rates was in part the result of high pre-plant soil NO3-N and NH4-N levels. Total phenolics and chlorogenic acid of artichoke heads increased as the harvesting season progressed and were highest at 50% ETc during mid- and late harvests in one season. Based on these results, we estimate that under these environmental conditions, ≈700 mm (for a bare soil system) of water inputs and 120 kg ha-1 or less of N (rate depending on soil available N) appear sufficient to obtain high marketable yields, superior size, and nutritional head quality of artichokes.
The use of organic amendments in agriculture could sustain crop production and preserve the
agroecosystem, due to their importance in the conservation of organic matter in soil. The objective of
this research was to evaluate the effects of differing organic fertilizers and of previous crops on lettuce
growth, nutritional status and yields. The effects on soil characteristics were further investigated.
The research was carried out during two years (2006 and 2007) at Metaponto (MT) in southern
Italy, on lettuce crops cultivated after eggplant and melon to avoid their continuous cropping. The
effects of application of a mineral fertilizer (MF), and of three treatments with organic fertilizers
(commercial stable manure - OM; anaerobic digestate based on wine distillery wastewater - AD;
composted municipal solid organic wastes coming from the separate collection - MSW) were studied.
Head average weight, leaf area index, nitrate content and SPAD readings during the cropping cycles
did not show significant differences among fertilizer treatments. On the contrary, marketable yield
and head average weight at the harvest presented significantly different among the three organic
fertilizers. The average marketable yield and head average weight of organic fertilizers experimental
(AD and MSW treatments) decreased of 16 and 17%, respectively, compared to OM treatment. The
previous melon crop influenced positively all analyzed parameters of the lettuce compared with previous
eggplant crop. The previous melon crop reached the highest marketable yield with an increase
of 59% compared with previous eggplant crop. Compared to the mineral fertilizer, the organic ones
significantly increased the extracted fraction of soil organic carbon (6.9, 10.7 and 14.9% for OM,
AD and MSW, respectively), without significant changes for the humic and fulvic content.
Fusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum J. H. Owen, results in considerable yield losses for cucumber plants. A bio-organic fertilizer (BIO), which was a combination of manure composts with antag-onistic microorganisms, and an organic fertilizer (OF) were evaluated for their efficiencies in controlling Fusarium wilt. Application of the BIO suppressed the disease incidence by 83% and reduced yield losses threefold compared with the application of OF. Analysis of microbial communities in rhizosphere soils by high-throughput pyrosequencing showed that more complex community structures were pres-ent in BIO than in OF treated soils. The dominant taxonomic phyla found in both samples were Proteobacteria, Firmi-cutes, Actinobacteria and Acidobacteria among bacteria and Ascomycota among fungi. Abundance of beneficial bacteria or fungi, such as Trichoderma, Hypoxylon, Tritir-achium, Paenibacillus, Bacillus, Haliangium and Strepto-myces, increased compared to the OF treatment, whereas the soil-borne pathogen, Fusarium, was markedly decreased. Overall, the results of this study demonstrate that the appli-cation of the BIO was a useful and effective approach to suppress Fusarium wilt and that the high-throughput 454 pyrosequencing was a suitable method for the characteriza-tion of microbial communities of rhizosphere soil of cucumber.
Globe artichoke (Cynara cardunculus L. subsp. scolymus (L.) Hayek, (formerly Cynara scolymus L.) represents an important component of the Mediterranean diet, and is a rich source of bioactive phenolic compounds, and also inulin, fibre and minerals. In addition, artichoke leaf extracts have long been used in folk medicine, particularly for liver complaints. These therapeutic properties have been often been ascribed to the cynarin (1,3-O-dicaffeoylquinic acid) content of these extracts. In various pharmacological test systems, artichoke leaf extracts have exhibited hepatoprotective, anticarcinogenic, antioxidative, antibacterial, anti-HIV, bile-expelling, and urinative activities as well as the ability to inhibit cholesterol biosynthesis and LDL oxidation. These broad therapeutic indications cannot be ascribed to a single, but to several active compounds that together generate additive or synergistic pharmacologic effects; these include mono-and dicaffeoylquinic acids, and flavonoids such as luteolin and its 7-O-glucoside. Artichoke by-products such as leaves, external bracts and stems that are produced by the artichoke processing industry, represent a huge amount of discarded material (about 80–85% of the total biomass of the plant), which could be used as a source of inulin but also of phenolics, and should be considered as a raw mate-rial for the production of food additives and nutraceuticals.
The mineralization of organic forms of phosphorus (P) in soil contributes significantly to plant P uptake, although quantification
of organic P mineralisation has been impeded by methodological difficulties. An isotopic dilution method, based on tracer
kinetic theory, was used to study the organic P flux rates for unamended and green manure amended soil in an incubation experiment
carried out over 35days. Firstly, the specific activity (SA) between two points of time as affected by dominant biological
processes (under conditions of constant soil respiration rates) was determined in a series of successive labelling incubation
experiments. Secondly, the instantaneous specific activity (instSA) between two points of time was also determined by shaking an unlabelled soil with 33P, i.e. soil samples that were not labelled with 33P, but kept under conditions identical to the labelled soil samples. This gives the net size of the exchangeable inorganic
P pool in the labelling experiments at two points of time during incubation. The SA dilution in the labelling experiments
at a constant exchangeable inorganic P pool between two times was attributed to the release of non-labelled inorganic P from
the organic P pool by mineralisation. The daily gross organic P mineralisation rates for the 21days of incubation were 0.06
and 0.27mgPkg−1 day−1 for unamended and green manure amended soils, respectively. The study demonstrated that green manure amendment contributed
to an overall increase in soil P availability through enhanced organic P mineralisation.
Core Ideas
Soil biological activity is a key indicator for productivity and environmental quality.
The flush of CO 2 possesses many qualities of a robust soil test.
Field calibration is underway to relate the flush of CO 2 to nitrogen availability.
Health of agricultural soils depends largely on conservation management to promote soil organic matter accumulation. Total soil organic matter changes slowly, but active fractions are more dynamic. A key indicator of healthy soil is potential biological activity, which could be measured rapidly with soil testing services via the flush of CO 2 during 1 to 3 d following rewetting of dried soil. The flush of CO 2 is related to soil microbial biomass C and has repeatedly been shown strongly related to net N mineralization during standard aerobic incubations. New research is documenting the close association with plant N uptake in semicontrolled greenhouse conditions ( r ² = 0.77, n = 36). Field calibrations are underway to relate the flush of CO 2 to the need for in‐season N requirement in a variety of crops. An index of soil biological activity can and should be determined to help predict soil health and soil N availability.
Legumes represent an important N source in organic vegetable rotations. Since the amount of N2 fixed as well as N mineralisation from legume biomass are highly variable, N availability does often not match the requirements of following crops. The production of grain legume seeds followed by their temporary storage and application as N fertilizer may represent a flexible and controllable alternative to traditional legume green manures. In two field experiments, narrow-leaved lupine was investigated as N source for subsequent white cabbage and beetroot and was compared to two grass-clover treatments, in which cut herbage was either removed from the sward or remained as mulch. Symbiotic N2 fixation was highest for cut grass-clover, averaging about 350 kg ha⁻¹. Mulching reduced N2 fixation by on average 57%. Lupine N2 fixation was largely comparable to that of mulched grass-clover swards. Net N mineralisation from grass-clover residues within the year of their incorporation was positively related to the percentage of clover (R² = 0.93). Application of coarsely milled lupine seeds on plots previously cropped with lupines resulted in an N supply for cabbage being higher or equal to that after mulched grass-clover. Residual effects on the N supply for beetroot, grown in the third rotational year following white cabbage, averaged −2 and 28 kg N ha⁻¹ for lupine and grass-clover, respectively. In conclusion, lupines may provide a highly flexible N source alternative to frequently mulched grass-clover swards. Further attention should be directed towards the utilization of cut forage legume herbage as mobile N source.
Tillage practices are critical for sustaining soil quality necessary for successful crop growth and productivity. A three-year study (2012–2014) was carried out to evaluate the influence of strip and conventional tillage practices and three water status levels [T1 = 100% of evapotranspiration (ET) demands, T2 = 0.75T1and T3 = 0.5T1] on plant morphology, physiology, yield and quality of triploid (seedless) watermelon (Citrullus lanatus cv. Magestic). Soil chemical and biological properties were also assessed at the end of the experimental study. Tillage practices (strip or ST and conventional or CT) started in 2009 and are being carried out to the present date of 2016. Irrigation was established using a center pivot system. Photosynthesis rate (Pn), stomatal conductance (gs), and chlorophyll content index (SPAD) were measured at flowering, fruit development and harvest stage and vine length measured at the harvest stage. Total marketable yield and fruit quality (firmness and sugar content) were determined during the harvest period. Soil chemical and microbial analysis were conducted at the end of the experimental period (March 2015). No significant differences (P = 0.05) were found between water deficit treatments in vine length, SPAD, Pn, gs, fruit firmness, and sugar content during the three-year study, except for vine length in 2013. But, marketable yield from T1 treatment was significantly higher (P = 0.03) than T3 in 2013. Vine length and SPAD measured from the ST plots were higher than CT, especially in 2012. Interestingly, marketable yield from ST was 8.6, 9.7 and 14.9 t ha−1 higher than CT in 2012, 2013 and 2014, respectively. Additionally, fruit sugar content under ST was statistically higher (P = 0.05) than those from CT. After 6 years of tillage practices (2009–2015) in the same site, ST increased total bacteria by 49%, active bacteria by 27%, active and total fungi by 37%, nematodes by 275%, and electrical conductivity by 14% compared to CT. However, ST significantly increased root-feeding nematodes (harmful to plant roots) and reduced phosphorus and nitrate-N compared to CT. Although long-term studies aimed at assessing soil quality and cumulative yield are required to further validate our results, yield and fruit quality (sugar content) responses were consistent across three years and with promising abundance of soil microbial activities.
The objective of this study was to evaluate effects of spent mushroom substrate (SMS) and chicken manure compost (ChMC) on growth, yield, and fruit quality of honeydew melon and to determine the most suitable rate of SMS for honeydew melon production. Honeydew melon seedlings grown in four different rates of SMS were planted in the net house with two different organic material rates (M1, M2). The experiment was arranged in a split-plot design. The results showed that increasing of organic materials in the net house increased growth, yield, and quality of honeydew melon, due to enhancing of pH, organic matter (OM,) and the nutrient concentrations in the soil. However, growing media with 40 % SMS + 60 % ChMC in the nursery period and the rate of 10 tons SMS + 10 tons ChMC ha−1 in the net house period gave the best yield and fruit quality of honeydew melon.
Cynarin (CYN) is the main derivative of caffeoylquinic acid, found in leaves and heads of artichoke. It may have hepatoprotective, antiatherosclerotic, antioxidative, choleretic, and cholesterol-lowering effects. We tested the effects of various doses of CYN on the proliferative potential, survival, morphology, and stress response (SR) markers heme oxygenase-1 (HO-1) and heat shock protein-70 (HSP70) in normal human skin fibroblasts (FSF-1), telomerase-immortalized mesenchymal stem cells (hTERT-MSC), and cervical cancer cells (HeLa). The effects of CYN on cell proliferation and morphology were dose- and cell type-dependent, with 500 µM CYN as the upper limit for all cell types. While the growth and proliferation of cells decreased after exposure to 75 µM CYN for 3 days, overall survival of FSF-1 and hTERT-MSC was higher than that of HeLa cells. Furthermore, CYN induced the oxidative SR marker HO-1 in both fibroblasts and stem cells in a biphasic manner. A slight induction of HSP70 was observed only in the stem cells. Thus, CYN may be useful for protection against the growth and survival of potentially cancerous cells and may promote longevity of normal cells by inducing SR proteins. Further advanced research related to CYN and artichoke is recommended.
Remediation of abandoned mine tailing sites are a challenge due to lack of infrastructure and funding.•We show that fertilizer and low levels of organic matter application (wood chips or paper mill sludge) improve tailing physical structure and increase the cover of seeded grasses and Medicago sativa after two years, even though nutrient levels increases were short lived.•Increased grass cover increased the survival of native Picea mariana tree seedlings, suggesting conditions on the site were now appropriate for colonization by native species.
Many studies have confirmed the validity of plant cover and organic farming in ameliorating soil quality. The goal of this study was to investigate the efficiency of rehabilitation practices in a degraded soil ecosystem consisting of: (i) organic or inorganic fertilization; and (ii) presence or absence of almond trees. The experiments were carried out for 2 years in the South of Italy in three fields characterized by different slope (0%, 2%, and 6%). Each field was split up into two parts, one assigned to organic fertilization and the other assigned to mineral fertilization, and planted with almond trees using GF677 or Franco rootstocks. The results showed that the organic fertilization, particularly in the presence of the Franco rootstock, resulted more effective in increasing soil organic matter content and microbial activity especially in the 0% and 2% slopes. However, in the 6% slope, where a lower soil metabolism was observed, an improvement of chemical and biochemical soil properties was generally evident for both fertilization systems. The Franco rootstock improved soil quality and maintaining a good production, whereas the GF677 has exploited more soil resources, resulting in a higher growth and yield; therefore, the use of almond tree with Franco rootstock associated with organic matter application is a useful practice in order to preserve soil quality and to rehabilitate degraded soils. Copyright © 2013 John Wiley & Sons, Ltd.
Organic matter and nutrients in municipal sewage sludge (SS) and chicken manure (CM) could be recycled and used for land farming to enhance fertility and physical properties of soils. Three soil management practices were used at Kentucky State University Research Farm, Franklin County, to study the impact of soil amendments on kale (Brassica oleracea cv. Winterbar) and collard (Brassica oleracea cv. Top Bunch) yields and quality. The three soil management practices were: (i) SS mixed with native soil at 15 t acre(-1), (ii) CM mixed with native soil at 15 t acre(-1), and (iii) no-mulch (NM) native soil for comparison purposes. At harvest, collard and kale green plants were graded according to USDA standards. Plants grown in CM and SS amended soil produced the greatest number of U.S. No. 1 grade of collard and kale greens compared to NM native soil. Across all treatments, concentrations of ascorbic acid and phenols were generally greater in kale than in collards. Overall, CM and SS enhanced total phenols and ascorbic acid contents of kale and collard compared to NM native soil. We investigated the chemical and physical properties of each of the three soil treatments that might explain variability among treatments and the impact of soil amendments on yield, phenols, and ascorbic acid contents of kale and collard green grown under this practice.
ADDITIONAL INDEX WORDS. sustainable agriculture, fertilizers, compost, green manure crops SUMMARY. Fertilization is the most expensive cultural practice for the increasing numbers of organic vegetable growers in the United States. Nitrogen (N) is the most important and costly nutrient to manage, and cost-effective N management practices are needed for efficient organic vegetable production. There is a wide array of organic N sources available, but they vary in cost, N content, and N availability. Compost and cover crops are commonly used sources of N for vegetables because they are relatively inexpensive and offer additional nutrients or soil improvement qualities in addition to N. Studies have shown that compost quality factors that affect N mineralization vary by source and among different batches from the same source. Compost carbon to N ratio should be equal to or less than 20:1 to assure net short-term mineralization. Cover crops also vary in N content and mineralization rate after incorporation. Leguminous cover crops decompose and release N more rapidly than grass or cereal cover crops at the preheading stage typically incorporated. Even the most efficient N-supplying composts, cover crops, or other organic N sources do not release appreciable N to a subsequent crop beyond 6 to 8 weeks from incorporation, and this burst of early N may not synchronize with N requirements for many vegetable crops. Other potential organic fertilizer N sources have been evaluated for vegetables, and they vary in N cost and N mineralization rate. Materials evaluated include seabird guano, liquid fish, feather meal, corn meal (Zea mays), blood meal, and liquid soybean meal (Glycine max) among others. Of those evaluated, feather meal, seabird guano, and liquid fish stand out as more economical organic sources of available N. Organic sources generally lack uniformity and are bulky, unstable, and inconsistent as a group, and this contributes to additional hidden management costs for organic growers. Liquid organic N sources for use in microirrigation systems may have additional disadvantages caused by loss of valuable nutrient N that is removed by filters.
To decrease the potential for adverse environmental impacts of N in agroccosystems, there is increasing emphasis on improving N efficiency of organic and inorganic sources. Greater reliance on organic N sources can cause short-term crop yield decreases. Consequently, a study was conducted to determine the effect of decreasing rates of inorganic N during a transition from inorganic to organic N sources. The approach was to grow four crops of maize (Zea mays L.) during a period of 306 d in the greenhouse on soils that varied widely in organic matter and biological activity because of long-term residue and fertilizer management. Treatments were arranged as a complete factorial with the following factors: four soils obtained from the Residue Utilization Plots (RUP), Columbia Basin Research Center, Pendleton, OR (beef manure or pea [Pisum sativum L.] vine residue, 0 or 90 kg N ha-1, applied biennially since 1931); four greenhouse amendments (pea vine, composted beef or poultry manure, or control); and four rates of N fertilizer (0-1600 mg N [2 kg]-1 soil as NH4NO3). In the absence of organic residue or N fertilizer, soil from the manure RUP produced greater dry matter yield (DMY) and plant N uptake than soil from the other RUP treatments. There was no net N mineralization from beef manure added in the greenhouse. Between 10 and 30% of the total poultry manure and pea vine N added was taken up by the four maize crops. Results showed that, by the fourth crop, when inorganic N applications had decreased to zero, plant productivity by organic residues was best maintained by pea vine residue or poultry manure.
Amounts of manure generated by concentrated animal operations often exceed the capacity of nearby land, and stricter environmental regulations lead to creation of pockets of highly impacted sites within a watershed basin. Linking forage production with manure utilization can be an effective approach for addressing both the problems of manure disposal and impact reductions on water quality. In general, cropping patterns, climate, topography, and fertilization practices affect concentrations of nutrients, including N and P in runoff waters. Forage plants include diverse groups of grasses and legumes adapted to different climatic zones and varying soil fertility. To optimize the P remediation in affected sites, knowledge of P forms and soil properties is crucial. Given the possibility of producing high quality and quantity of herbage from such impacted agricultural areas, it would be worthwhile to utilize existing knowledge of herbage production from differentially manured soils and optimize nutrient uptakes. This review attempts to consolidate the available information on the potentials and limitations of pasture usage for phytoremediation of P in affected soils. Such herbage production systems may not only be environmentally sound for recycling of nutrients and minimizing nutrient loss to water bodies, but they may also help farmers/producers to maintain a profitable business enterprise.
Maximizing the environmental and economic benefits of cover crops partially depends on an accurate estimate of the N fertilizer requirement of subsequent crops. Four trials involving cover crop, tillage, and N rate variables were conducted from 1992 to 1995 in southcentral Ontario on well-drained Typic Hapludalf soils. Rye (Secale cereale L.), oilseed radish [Raphanus sativus (L.) var. oleiferus Metzg (Stokes)], oat (Avena sativa L.), and red clover (Trifolium pratense L.) cover crops were established after winter wheat (Triticum aestivum L.) to evaluate their effects on soil NO3-N levels as well as subsequent corn (Zea mays L.) grain yield response at fertilizer rates of 0 and 150 kg N ha-1. Corn response to cover crops was compared in autumn plow and no-till tillage systems. Within no-till, autumn vs. spring chemical kill for red clover and rye was also evaluated. Although red clover biomass N yields were usually at least double those with other cover crops, all cover crops were equally effective at lowering residual soil NO3-N concentrations following wheat harvest. Presidedress NO3-N concentrations after autumn-killed or plowed red clover were at least 24% higher than after any other cover crop. Grain corn yield responses indicated that red clover substantially enhanced N availability to corn in both autumn plow and no-till systems, but that oilseed radish, oat, and rye cover crops did not enhance N availability to succeeding corn, compared with the no cover treatment, in either tillage system. Furthermore, the presidedress NO3-N test reliably estimated N fertilizer requirements of corn following all cover crop systems except spring-killed red clover.
The positive role of green manuring in crop production has been known since ancient time. Importance of this soil ameliorating practice is increasing in recent years because of high cost of chemical fertilizers, increased risk of environmental pollution, and need of sustainable cropping systems. Green manuring can improve soil physical, chemical, and biological properties and consequently crop yields. Furthermore, potential benefits of green manuring are reduced nitrate (NO3 ) leaching risk and lower fertilizer N requirements for succeeding crops. However, its influence may vary from soil to soil, crop to crop, environmental variables, type of green manure crop used, and its management. Beneficial effects of green manuring in crop production should not be evaluated in isolation; however, in integration with chemical fertilizers. The objective of this article is to review recent advances in green manuring practice, in the context of potential benefits and drawbacks in use of this practice for annual crop production and sustain soil health and fertility.
The objectives of this study were to modify the Mehlich 2 (M2) extractant to include Cu among the extractable nutrients, retain or enhance the wide range of soils for which it is suitable and minimize it's corrosive properties. The substitution of nitrate for chloride anions and the addition of EDTA accomplished those objectives. The new extracting solution, already designated Mehlich 3 (M3) is composed of 0.2N CH3COOH‐0.25N NH4N03‐0.015NNH4F‐0.013NHN03‐0.001M EDTA. Extractions from 105 soils using M3, M2, Bray 1 (Bl) and Ammonium Acetate (AA) were compared to evaluate the new extractant. The quantity of F extracted by M3 exceeded that by M2 20% and that by Bl 4% but the results from all extractions were highly correlated. Extractions of both K and Mg by M3 were 6–8% higher than those by AA and 3–4% higher than those by M2, but, again, there was high correlation among methods. Addition of EDTA increased Cu extractions by 170%, Mn by 50% and Zn by 25%. Cu extractions by M3 correlated with those from the Mehlich‐Bowling method. High correlations between Mn, as well as Zn, extracted by M3 and M2 were shown.
An automated CHN Analyzer was compared with the Walkley‐Black and Kjeldahl methods for organic carbon (C) and nitrogen (N). Four organic compounds, twenty nine plant materials and five soils were tested. The CHN Analyzer gave C and N values that were not significantly different (P<0.05) to the theoretical weight percents of the organic compounds. The Walkley Black method gave soil C values significantly lower (P<0.05) than those obtained with the CHN Analyzer. The Kjeldahl method gave soil N values significantly lower (P<0.05) than the CHN Analyzer on three of five soils tested. The discrepancies observed between methods appear to be due to different oxidation efficiencies. CHN Analyzer and Kjeldahl N analyses were not significantly different (P<0.05) for the plant materials except where samples contained greater than 0.7% NO3‐N. Potassium nitrate was also added as a spike to a tall fescue sample. Based on recovery of the spiked NO3‐N, the Kjeldahl method was a poor measure of total N for plant materials containing greater than 0.7% NO3‐N. The findings suggest the CHN Analyzer can be used for the rapid, accurate and simultaneous determination of C and N in plant and soil samples.
Nitrate (NO3 ) meters have been used effectively for crop nitrogen (N) management in many crops, including corn and cabbage. The use of a Cardy NO3 meter to assess the N status of the carrot crop could improve the utilization of applied N, but critical NO3‐N concentrations are required. Two carrot cultivars were grown on mineral and organic soils over 3 years at five N application rates to establish critical sap and soil NO3‐N concentrations and to identify the effects of soil type and cultivar. Although a yield response to N application occurred on mineral soil in 2 of 3 years, consistent critical sap NO3‐N concentrations could not be established because of variability among years, cultivars, and soil types. Critical soil nitrate concentrations were highly variable, but values of 31 to 36 mg · L NO3‐N could be established for the early sampling date to 30 cm deep. Sap NO3‐N concentrations cannot be used alone for N analysis of carrots, but early‐season soil NO3‐N assessment could be useful in adjusting N‐fertilization practices.
This review is concerned with the summary and evaluation of the results from more than 150 investigations comparing the quality of conventionally and organically produced food or of foods produced with the aid of different fertilisation systems. Cereals, potatoes, vegetables, fruits, wine, beer, bread, cakes and pastries, milk, meat, eggs and honey, as well as products made from them, have been included in the review. Most of the studies evaluated are physico-chemical investigations of concentrations of desirable and undesirable ingredients, pesticide residues, contaminants, sensory analyses and feed experiments with animals. Nutritional studies in humans and experiments which used holistic methods of analysis are also included. Since different methods of sampling were used in the investigations, a summary evaluation of individual results is extremely difficult. Even when the sampling methods are of the same type, a great many factors have to be taken into consideration which are not directly related to the production system but which do influence food quality to a large degree. Despite the heterogeneity of the sample material, some differences in quality between products from conventional and organic farming or foods produced with the aid of different fertilisation systems have been identified. © 1997 SCI
A 13-year long-term experiment on the Loess Plateau of China was used to evaluate the effect of two different fertilizer regimes on the soil's physical/hydraulic properties. The fertilizer regimes included (i) control without any fertilizer (C), (ii) applications of chemical fertilizer (NPK), and (iii) applications of chemical fertilizer plus dairy manure (MNPK). Undisturbed soil cores were collected from the field to determine soil water retention curves and hydraulic conductivity (saturated and unsaturated). In addition, gravimetric water content, soil bulk density, porosity and saturated hydraulic conductivity were measured several times during the crop growing season to check seasonal variations. Annual application of manure increased soil water retention at the two soil depths tested (0–5 and 10–15 cm) relative to the control treatment (P ≤ 0.1), by 13 to 32% at tension ranges from 0 to 300 kPa for the 0–5 cm layer, and by 5 to 19% from 0 to 2 kPa for the 10–15 cm layer. The field soil water content was also significantly increased at 0–10 cm depth (P ≤ 0.05). Saturated hydraulic conductivity did not show any significant differences among treatments on the sampling dates due to large variations in the data. In contrast, the MNPK and NPK treatments decreased unsaturated hydraulic conductivity compared with C at 0–5 cm depth. No significant differences between treatments in this variable were observed at 10–15 cm depth. Generally, NPK showed similar effects to C. Soil physical properties (bulk density and porosity) showed significant seasonal variations.
Soil health is the capacity of soil to function as a vital living system, within ecosystem and land-use boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Anthropogenic reductions in soil health, and of individual components of soil quality, are a pressing ecological concern. A conference entitled ‘Soil Health: Managing the Biological Component of Soil Quality’ was held was held in the USA in November 1998 to help increase awareness of the importance and utility of soil organisms as indicators of soil quality and determinants of soil health. To evaluate sustainability of agricultural practices, assessment of soil health using various indicators of soil quality is needed. Soil organism and biotic parameters (e.g. abundance, diversity, food web structure, or community stability) meet most of the five criteria for useful indicators of soil quality. Soil organisms respond sensitively to land management practices and climate. They are well correlated with beneficial soil and ecosystem functions including water storage, decomposition and nutrient cycling, detoxification of toxicants, and suppression of noxious and pathogenic organisms. Soil organisms also illustrate the chain of cause and effect that links land management decisions to ultimate productivity and health of plants and animals. Indicators must be comprehensible and useful to land managers, who are the ultimate stewards of soil quality and soil health. Visible organisms such as earthworms, insects, and molds have historically met this criterion. Finally, indicators must be easy and inexpensive to measure, but the need for knowledge of taxonomy complicates the measurement of soil organisms. Several farmer-participatory programs for managing soil quality and health have incorporated abiotic and simple biotic indicators. The challenge for the future is to develop sustainable management systems which are the vanguard of soil health; soil quality indicators are merely a means towards this end.
Erosion changes soil properties, especially physical properties, mainly because it removes surface soil rich in organic materials and exposes lower soil layers. In 1988, a study was established to determine the effects of soil erosion and long-term manure applications on selected soil phys ical properties and corn (Zea mays L.) production. After 10 years of an nual manure applications, soil core samples were collected in 7.6-cm in crements at three depths, 0 to 7.6, 15 to 22.6, and 30 to 37.6 cm, to determine soil bulk density (� b), hydraulic conductivity of saturated soil (Ks), and water retention. Bulk density and Ks increased slightly with ero sion level. Water retention did not change in the surface 7.6 cm, but it did decrease with increasing erosion level at deeper depths. Long-term application of manure decreasedb by 10%, whereas Ks was doubled in the top 7.6 cm of soil. Manure increased soil-water retention capacity and decreased differences in water retention between erosion levels, espe cially at low suctions (0 to 20 kPa). Soil carbon content correlated well with water retention andb. Corn grain yields in 1997, 1998, and 1999 were 15, 6, and 14% less, respectively, in the severe than in the slight ero sion phase. Long-term manure additions increased corn grain yields by 19% in 1998 and by 25% in 1999. Increased yield from manure additions was likely related to an enhancement in water retention. Results from this study show that long-term manure application is a possible management alternative for restoring the physical properties and crop productivity of eroded soil. (Soil Science 2003;Volume 168:888-899)
To survey existing literature comparing nutrient content of organic and conventional crops using statistical methods to identify significant differences and trends in the data.
Published comparative measurements of organic and conventional nutrient content were entered into a database for calculation. For each organic-to-conventional comparison, a percent difference was calculated: (organic - conventional)/conventional x 100. For nutrients where there was adequate data, the Wilcoxon signed-rank test was used to identify significant differences in nutrient content as represented by the percent difference. Mean percent difference values were also calculated for each significant nutrient by study and by vegetable for the most frequently studied vegetables. The nutrient content of the daily vegetable intake was calculated for both an organic and conventional diet.
Organic crops contained significantly more vitamin C, iron, magnesium, and phosphorus and significantly less nitrates than conventional crops. There were nonsignificant trends showing less protein but of a better quality and a higher content of nutritionally significant minerals with lower amounts of some heavy metals in organic crops compared to conventional ones.
There appear to be genuine differences in the nutrient content of organic and conventional crops.
The potential use of soil biotic activity as an indicator of productivity, sustainability and pollution
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Elliott E. 1994. The potential use of soil biotic activity as an indicator of productivity, sustainability and pollution. In:
Pankhurst C, Doube B, Gupta V, editors. Soil biota: management in sustainable farming systems. Melbourne: CSIRO;