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Published: 28 August 2021
by MDPI
Abstract:
Adoption of suitable organic fertilizers and soil mulching are useful tools to enhance soil quality, which will inevitably lead to improved growth and yield of crops. Little is known about the soil organic amendments and Azolla (Azolla pinnata) under soil organic mulching on the growth and yield of squash plant (Cucurbita pepo L.). A comparative study mainly focused on the impacts of organic fertilizer treatments on soil fertility and squash growth under wheat straw mulch was conducted on wooden boxes filled with silty loam soil. Wheat straw, as an organic mulch, and five organic-fertilization treatments were added to the soil. Wheat straw with a size of <2 cm was added to the soil surface with a 2 cm thickness. The fertilization treatments were: control (CO), chemical fertilizer (CF), compost (CT), vermicompost (VC), and dry Azolla (DA). Wheat straw mulch had positive effects on the soil properties, growth, and yield. The maximum fruit yield was obtained from the soil fertilized with DA under wheat straw mulch, while the lowest one was found in the control without mulching. Azolla and organic fertilizers showed a remarkable superiority over the mineral fertilization in increasing the soil fertility as well as the growth and quality of squash fruits; this superiority increased under the wheat straw mulching system. The application of recommended mineral fertilization (CF), compost (CT), vermicompost (VC), and dry Azolla (DA) under wheat straw mulch increased the soil available-N by 2, 20, 12, and 29%, respectively, above the control (CO), while these organic fertilizers without mulching increased the soil available-N by 11, 32, 26, and 48%, respectively. The production of vegetable crops such as squash plants requires the addition of organic fertilizers and mulching to increase yield and quality of fruits.
AnandKumar Naorem, Somasundaram Jayaraman, S. K. Udayana, N. A. K. Singh
Conservation Agriculture: A Sustainable Approach for Soil Health and Food Security pp 267-287; https://doi.org/10.1007/978-981-16-0827-8_12

Abstract:
To feed around 9.8 billion people by 2050, it is equally important to increase food production while maintaining the sustainability of the environment. Conservation agriculture (CA) is one of the approaches to manage agro-ecosystems in order to improve productivity, increase the profitability and food security and enhance the resource base and environment. Although many researchers have pointed out the prospects and concerns of adopting CA in different climatic conditions, CA in arid regions raises uncertainties due to its extreme climates, most of the soils with low water holding capacity, high potential evapotranspiration, low and non-uniform distribution of rainfall and greater wind erosion. However, CA practices could benefit the arid agriculture through moderation/reducing of evaporation, regulating water and nutrient in soil and reducing wind erosion. Arid soils, largely characterised by low soil organic carbon (SOC), have the greater potential for higher C sequestration with the use of CA practices. Among the key components of CA, no-tillage (NT) coupled with mulching might be effective in distribution of the soil moisture at proper stage of the crop growth. The emission of CO2 flux from soil and soil salinity are reduced with the adoption of CA in arid soils with the use of cover crops. Due to better aeration and nutrient movement in CA land, beneficial bacterial community and diversity are promoted. However, for CA to work effectively in arid regions, the three components of CA such as minimum disturbances of soil through no- and reduced-tillage, permanent soil cover and crop rotation must be critically followed together or simultaneously for improving soil health, crop productivity through high nutrient and water efficiency, carbon sequestration, mitigation of climate change and sustainability.
Agniva Mandal, Salwinder Singh Dhaliwal, Pabitra Kumar Mani, Amardeep Singh Toor
Published: 13 August 2021
Advances in Organic Farming pp 17-37; https://doi.org/10.1016/b978-0-12-822358-1.00014-6

Abstract:
Conservation agriculture (CA) is a resource-saving strategy encompassing three broad principles viz., minimum soil disturbance, diversified crop rotation and adequate soil cover through residue retention. Nowadays organic farmers are encouraged to adopt conservation practices to ensure soil quality and sustainability along with food security. In this chapter, we aimed to disseminate comprehensive knowledge regarding recent findings, advantages, drawbacks and opportunities of introduction of conservation practices in organic farming (OF). The possible potential benefits of adopting CA in OF are less soil erosion and degradation due to improved soil structure, rise in soil carbon stock, augmented biomass and diversity of macro- as well as micro-organisms, and reduced loss of nutrients through run-off and/or leaching. As CA and OF relies on principles of contrasting strategies of practices, introduction of CA in OF also poses challenges like difficulties in weed control, soil compaction, restricted nutrient availability due to slow mineralization rate and restricted choice of crops. Apart from these, some other constraints such as unavailability of suitable equipment, low incentives and funding from Governments and lack of organic market development strategies are also hindering the spontaneous adoption of CA by the organic farmers. Thus, practicing conservation techniques in OF strongly requires modification of traditional management practices into well optimized practices with some degree of flexibility depending upon pedo-climatic conditions, equipment availability and targeted objectives of farmers.
, Philipp Götze, Heinz‐Josef Koch
Journal of Plant Nutrition and Soil Science; https://doi.org/10.1002/jpln.202100122

Abstract:
Background Crop rotations with sugar beet (SB) vary in accompanying crops, affecting the organic matter input into the soil and thus the soil organic carbon (SOC) stocks. Furthermore, the impact of aboveground SB residues themselves on SOC stocks is unclear. Aims The aims of this study were to analyze the effects of three SB rotations and different amounts of SB residues on SOC stock development. Methods In a field experiment started in 2006, three different SB crop rotations [(1) SB–winter wheat (WW)–WW, (2) SB–WW–silage maize (SM), and (3) SB–WW–winter oilseed rape (WOR)–WW–WW–grain pea (GP)] were sampled for SOC stocks in 0–10, 10–20 and 20–30 cm soil depth in spring of 2018 and 2019. Further plots with an SB–WW–WW rotation received either no or the doubled amount of aboveground SB residues and were sampled as described above. Results After four rotations, doubled SB residues led to significantly higher SOC stocks in 0–10 cm depth compared to the removal of SB residues. However, the effect was relatively low with 12% of the added residue-C being recovered in the soil. Comparing different SB crop rotations, SOC stocks in 0–20 cm depth were significantly higher in the SB–WW–WW compared to the SB–WW–SM rotation, while the SB–WW–WOR–WW–WW–WW–GP rotation was intermediate. Differences in SOC stocks were likely due to the different amounts and possibly quality of crop residue C input. Conclusion In total, the accompanying crops rather than the share of SB seem to be decisive for SOC development in SB rotations.
Published: 15 July 2021
by MDPI
Abstract:
Reducing tillage intensity and increasing crop diversity by including perennial legumes is an agrotechnical practice that strongly affects the soil environment. Strip tillage may be beneficial in the forage legume–cereals intercropping system due to more efficient utilization of biological nitrogen. Field experiments were conducted on a clay loam Cambisol to determine the effect of forage legume–winter wheat strip tillage intercropping on soil nitrate nitrogen (N-NO3) content and cereal productivity in various sequences of rotation in organic production systems. Forage legumes (Medicago lupulina L., Trifolium repens L., T.alexandrinum L.) grown in pure and forage legume–winter wheat (Triticum aestivum L.) strip tillage intercrops were studied. Conventional deep inversion tillage was compared to strip tillage. Nitrogen supply to winter wheat was assessed by the change in soil nitrate nitrogen content (N-NO3) and total N accumulation in yield (grain and straw). Conventional tillage was found to significantly increase N-NO3 content while cultivating winter wheat after forage legumes in late autumn (0–30 cm layer), after growth resumption in spring (30–60 cm), and in autumn after harvesting (30–60 cm). Soil N-NO3 content did not differ significantly between winter wheat strip sown in perennial legumes or oat stubble. Winter wheat grain yields increased with increasing N-NO3 content in soil. The grain yield was not significantly different when comparing winter wheat–forage legume strip intercropping (without mulching) to strip sowing in oat stubble. In forage legume–winter wheat strip intercropping, N release from legumes was weak and did not meet wheat nitrogen requirements.
, Hongtu Xie, Zhiwen Chen
Published: 7 June 2021
Soil and Tillage Research, Volume 213; https://doi.org/10.1016/j.still.2021.105091

Abstract:
Crop residue management is an important conservation practice which provides numerous benefits to soil-related structural components and processes in agricultural ecosystems. However, the current understanding of the effects of soil environmental changes induced by different amounts of crop residue mulch on regulating soil mesofauna remains poor. To address this issue, an experimental field study was carried out in the Conservation Tillage Research and Development Station of the Chinese Academy of Sciences located in northeastern China. No-till and different amounts of corn stover mulch were included in a randomized complete block design with the following treatments: no-till with no corn stover mulch (NT-0); no-till with 2.5 t ha−1 corn stover mulch (NT-33 %); no-till with 5 t ha−1 corn stover mulch (NT-67 %); no-till with 7.5 t ha−1 corn stover mulch (NT-100 %), and conventional tillage (CT) as a control treatment. Soil mesofauna were sampled in spring, summer, and autumn of 2016. The abundance, diversity, and composition of the mesofauna were measured to estimate the potential interacting effects on the mesofauna of no-till with different amounts of corn stover mulch. The results showed that compared with CT, no-till with corn stover mulch altered the mesofauna communities. NT-100 % harbored significantly more mesofauna than CT in spring, whereas higher densities of mesofauna were observed in NT-33 % and NT-67 % than other treatments in summer and autumn. The individual numbers of the majority of the mesofauna taxa in all no-till with corn stover mulch treatments were significantly higher compared with CT, particularly NT-100 % in spring and NT-67 % in summer and autumn. Although corn stover mulch had displayed beneficial roles in greatly contributing to the mesofauna assemblage, the relationship between the amount of corn stover mulch and the abundance of mesofauna changed across the growing season. The total density, richness, and the numbers of Oribatida, Isotomidae, Hypogastruridae, Neanridae, and Coleoptera had displayed significant linear relationships with the amount of corn stover mulch in spring. Meanwhile, the total density and the numbers of Mesostigmata, Hypogastruridae, Entomobryidae, and Diptera larvae had displayed significant 2nd degree polynomial relationships with the amount of corn stover mulch in summer and autumn. The results obtained in this study demonstrated that the corn stover mulch was the important factor in supporting more abundant and diverse mesofauna, however, the magnitude and direction of the effects of the amount of corn stover mulch on the mesofauna were highly seasonally specific.
Published: 3 June 2021
by MDPI
Sustainability, Volume 13; https://doi.org/10.3390/su13116356

Abstract:
Crop residues are widely considered as a biofuel source and used in livestock feeding, or are burned off to clean the field for tillage and planting. Nonetheless, crop residue burning poses serious threats to the soil stability and sustainability of the food chain. This study aimed to investigate the potential environmental impacts of wheat residues burning on declines in soil quality in developing (Iran) and developed (Italy) countries by analyzing metadata of the last 50 years. All metadata were provided from the ‘Food and Agriculture Organization of the United Nations’ (FAO) including wheat harvested area, annual production, and biomass burning, to assess the potential impact of crop residue burning on soil quality. In detail, the greenhouse gases (GHGs) emission, and energy and nutrient losses by the wheat residues burning were estimated. Our results showed a robust interdependence between wheat residues burning and environmental effects in both developed and developing systems. Accordingly, the global warming potential increased in Iran (4286 to 5604 kg CO2eq) and decreased in Italy (3528 to 1524 kg CO2eq) over the last 50 years. Amongst all nutrient losses, nitrogen represents the higher lost value in both countries, followed by potassium, sulfur, and phosphorus.
Published: 28 May 2021
by MDPI
Abstract:
On the semiarid Colorado Plateau, dryland farmers are challenged by degraded soils and unreliable precipitation. While cover crops have been shown to support soil fertility, control erosion, and enhance soil water capture, they also use limited soil water and, thus, may impact cash crop productivity in dryland systems. Most literature on cover crops comes from relatively humid climates, where yield penalties due to cover crops may be less pronounced. Two field trials were conducted in Southwestern Colorado to assess the short-term viability of cover crops in dryland systems in this region. The effect of cover crops on subsequent winter wheat (Triticum aestivum L.) yield ranged from a decrease of 78% to an increase of 13%, depending on the amount of cover crop biomass produced in the previous year. Cover crop biomass was inversely correlated with soil nitrate levels and soil water storage at wheat planting, which decreased by 0.39 mg kg−1 and 10 mm, respectively, per 1000 kg ha−1 of cover crop biomass produced. Less available soil water and immobilized N therefore appeared to contribute to wheat yield reductions. These impacts are particularly important for semiarid environments, where decomposition of residue is water-limited and soil water recharge depends on unpredictable precipitation patterns.
, Alexis Thoumazeau, Audrey Leopold, Pascal Lienhard, Stéphane Boulakia, Aurélie Metay, Tobias Sturm, Philippe Tixier, Alain Brauman, Bruno Fogliani, et al.
Published: 23 May 2021
Soil and Tillage Research, Volume 212; https://doi.org/10.1016/j.still.2021.105079

Abstract:
Conservation agriculture (CA) is one strategy with which both sustainability and productivity can be achieved by improving soil health. However, linkages between practices, soil health and cropping system performance remain poorly disentangled. We assessed the relationships between soil health and cropping system performance for three maize-based cropping systems in New Caledonia. Two CA systems, one with direct seeding into a mixed species dead mulch (CA-DM) and one into a stylo living mulch (CA-LM), were compared to a conventional tillage (CT) system. CA vs. CT experiment started in 2011, whereas the differentiation between CA-DM and CA-LM was initiated in 2017 only. In 2018, soil health was evaluated using Biofunctool®, a set of ten in-field tools that assess soil carbon transformation, structure maintenance and nutrient cycling functions. The performance of the three cropping systems were assessed by monitoring weeds, maize growth and yield components. Structural equation modelling (SEM) was used to disentangle the links between agricultural management, soil health and cropping system performance. Soil structure maintenance and nutrient cycling functions were higher under CA-DM and CA-LM than under CT, and carbon transformation function was higher under CA-DM than under CT and CA-LM. Overall, the soil health index (SHI) was 1.3-fold higher under CA systems than under CT. Cropping system management had both direct and indirect effects on soil functioning and crop productivity leading to a 1.3-fold higher yield under CA than under CT. The direct and indirect effects of CA systems on soil health had positive impacts on ecosystem services (i.e., productivity, weed regulation and soil ecosystem services). Such integrative approaches that account for the relationships and possible trade-offs between cropping system components enable a better understanding of the effects and the performance of practices, and support adaptive agricultural management.
, Bram Govaerts, Nele Verhulst, Andrew McDonald, Bruno Gérard
Published: 18 May 2021
Biological Conservation, Volume 259; https://doi.org/10.1016/j.biocon.2021.109167

Abstract:
Increased agricultural production through both intensification and extensification is a major driver of the current biodiversity crisis. As a response, two contrasting approaches have been advocated: ‘land sparing’, which minimizes demand for farmland by increasing yield, and ‘land sharing’, which boosts densities of wild populations on farmland but decreases agricultural yields. While these approaches have been useful in drawing attention to the impact of meeting the growing global demand for agricultural products on biodiversity, they have been driven mainly by conservation ecologists, and have often overlooked important issues related to farming. As agricultural scientists with practical experience in developing, testing and scaling alternative forms of agriculture in some of the most biodiversity-rich areas of Latin America, Eastern and Southern Africa and South Asia, we are pointing in this paper at what we see as being two major limitations of the land sparing/sharing framework: (1) the reliance on yield-density relationships that focus on trade-offs and overlook synergies between agriculture and biodiversity, and (2) the overemphasis on crop yield, neglecting other metrics of agricultural performance which may be more important to local farmers, and more strongly associated with positive biodiversity outcomes. It is our hope that this paper will stimulate other agricultural scientists to contribute to the land sparing/sharing framework, in order to develop together with conservation ecologists viable solutions for both improved agricultural production and biodiversity conservation.
Binaya Parajuli, , Min Luo, , Dara Park, Matthew Smith,
Soil Science Society of America Journal; https://doi.org/10.1002/saj2.20277

Abstract:
Conservation tillage (CS) is a major component of sustainable soil management. The objective of the study was to investigate soil carbon (C) and nitrogen (N) pools and the associated microbial activities in sandy Ultisols after 40‐year of CS and conventional tillage (CT). Soil samples were collected from fields under continuous CS and CT for 40 years (1979 to 2018) and subjected to a range of physio‐biogeochemical analyses. When compared with CT, CS increased total C, total N, and active C by 35%, 45%, and 44% at 0–5 cm, respectively, but not at 5–15 cm. In contrast, CT had 128% and 121% higher inorganic N and dissolved organic N at 5–15 cm depth, which was not observed at 0–5 cm. Respiratory CO2 production and organic N mineralization were found higher in CS soils than in CT soils at 0–5 cm, but both were higher in CT than CS at 5–15 cm. Concurrently with increased active C concentrations, potential activities of C‐cycling enzymes were higher in CS soils than CT soils at 0–5 cm, which however were not observed at 5–15 cm. The increased labile C supply stimulated microbial activities in CS soils at 0–5 cm, but at 5–15 cm, the higher N availability increased microbial biomass N and organic N mineralization potentials in CT than CS soils. The contrasting CS and CT impacts on C and N at different soil depths likely reflected the decouple of C and N cycling in the tested soils. This article is protected by copyright. All rights reserved
, S.P. Poonia, Rakesh Kumar, Rachana Dubey, Virender Kumar, Surajit Mondal, S.K. Dwivedi, K.K. Rao, Rahul Kumar, Manisha Tamta, et al.
Published: 3 May 2021
Field Crops Research, Volume 267; https://doi.org/10.1016/j.fcr.2021.108164

Abstract:
In the eastern Indo-Gangetic Plains (EIGP), conventional rice-wheat system has led to a decline in productivity, input-use efficiency, and profitability. To address these, a four-year field study was conducted to evaluate the performance of tillage and crop establishment (TCE) methods in rice-wheat-greengram rotation. The treatments included: 1) random puddled transplanted rice (RPTR) - conventional-till broadcast wheat (BCW) - zero-till greengram (ZTG); 2) line PTR (LPTR) - conventional-till drill sown wheat (CTW) - ZTG; 3) machine transplanted rice in puddled soil (CTMTR) - zero tillage wheat (ZTW) - ZTG; 4) machine transplanted rice in zero-till wet soil (ZTMTR) - ZTW - ZTG; 5) system of rice intensification (SRI) - system of wheat intensification (SWI) - ZTG; 6) direct-seeded rice (DSR) - ZTW - ZTG; and 7) zero-till DSR - ZTW - ZTG. During the initial two years, conventional rice system (PTR) recorded a 16.2 % higher rice grain yield than DSR system. Whereas in the fourth year, the rice yields under DSR and PTR were comparable. As compared to SRI/SWI, the average wheat yield in ZT system was significantly high, whereas in rice, SRI/SWI system was comparable with CT system. ZTW after non-puddled rice was at par to CTW after PTR. The ZT wheat produced 4.6 % more yield than CT system. DSR production system consumed 6.8 % less water compared to transplanted system. On the system basis, 10.8 % higher net returns were recorded with CA-based system compared to conventional system. The system energy productivity under CA-based production system was 14–36 % higher than PTR-based systems. CA-based system also led to 8–10 % lower global warming potential (GWP) than conventional methods. The current study indicated that as compared to conventional system, a significant gain in productivity, profitability and energy-use efficiency, and reduction in the environmental mitigation are possible with emerging alternative TCE methods. Long-term expansion and further refinement of these technologies in local areas need to be explored for the second green revolution.
, Jacques Avelino, Paula Fernandes, Philippe Letourmy, Régis Babin, Péninna Deberdt, Jean-Philippe Deguine, , Krishna Naudin, Béatrice Rhino, et al.
Published: 29 April 2021
Crop Protection, Volume 146; https://doi.org/10.1016/j.cropro.2021.105658

Abstract:
It has been suggested that increasing plant species diversity (PSD) in agroecosystems at different spatiotemporal scales reduces the impacts of crop pests and diseases as well as the dependence on synthetic plant protection products. This principle was applied to a range of tropical case studies. These studies involved various pests and pathogens with contrasting life history traits, different cropping systems (a cereal crop in conservation agriculture, vegetable crops in rotational and trap cropping systems, perennial crops in agroforestry) and various spatial scales of PSD deployment (field and farmscape). Here we review the outcomes of these studies, and discuss the lessons learned regarding synergies and tradeoffs associated with regulation effects provided by PSD. The major points are: 1) results contributed to solve local crop pest and disease problems such as bacterial wilt on tomato in Martinique, scarab beetles and witchweed on upland rice in Madagascar, fruitworms on tomato in Martinique and okra in Niger, fruit flies on cucurbit vegetables in Reunion, mirid bugs and black pod rot on cocoa in Cameroon, berry borer and leaf rust on coffee in Costa Rica; 2) the importance of cross-cutting issues regarding green manure, cover crops or companion plants across case studies at the field scale involving below-ground and aerial processes, were highlighted, particularly that of the within-species genetic variation of these plants; 3) based on the fruitworm/tomato case study, a dynamic and spatially-explicit individual-based model was developed as a generic tool to improve understanding of system functioning by assessing infestation patterns in response to main crop/trap crop relative attractiveness, spatiotemporal deployment of the main crop/trap crop and insect behavioral traits; 4) tradeoffs were highlighted regarding pest and disease complex management, single-option pest and disease control via several pathways based on a single PSD-deployment measure and other ecosystem services and disservices at various scales.
Published: 26 April 2021
by MDPI
Abstract:
A laboratory investigation of abrasive waterjet cutting of wheat straws was conducted. The work was aimed at a systematic characterization of the abrasive waterjet cutting capability of wheat straws, as a potential alternative to cutting discs currently adopted in no-till drills and planters for crop residue management. A two level 2IV73 fractional factorial design was applied to investigate the influence of abrasive waterjet process parameters on the cutting efficiency of wheat straws. Straw coverage thickness, water pressure, and orifice diameter were found to be the most significant ones. Experimental results suggest that straw cutting mechanism is mostly related to the hydraulic power of the jet. A multiple logistic regression was performed to model the relationship between the cutting efficiency and the jet power. The logistic model was then applied to estimate the average water and power consumption for wheat straw cutting during a no-tillage seeding operation. An average jet hydraulic power of 6400 W would be sufficiently high to guarantee 90% cutting efficiency in presence of heavy residue distribution. The experimental study shows that a small quantity of abrasive powder (50 g·min−1) allows one to increase the jet cutting capability of wheat straws, and to reduce the required maximum hydraulic power, compared to pure waterjet cutting. Results show are potentially relevant for field validation in agriculture based on no-tillage.
Published: 15 April 2021
Scientia Horticulturae, Volume 285; https://doi.org/10.1016/j.scienta.2021.110168

Abstract:
Growing nitrogen (N)-fixing green manure, such as red clover (Trifolium pratense L.), in blackcurrant (Ribes nigrum L.) plantation alleys for use as a plant-based fertiliser could potentially reduce the need for animal manure fertilisation in organic farming. Knowledge about nutrient release from plant-based fertilisers is limited. Therefore, a blackcurrant field experiment was conducted in Denmark (2016–2019) to investigate the effects of using red clover (Clover) as a plant-based fertiliser, compared to poultry manure (Poultry), on soil nutrient availability, plant nutrient status and blackcurrant yield. Four weeding/fertiliser placement strategies were included to assess the combined effects of weed suppression and fertiliser placement, forming the following four field experiment conditions: no weeding, surface-applied fertiliser (NO); no weeding, fertiliser incorporation (NOinc); weeding with a brush cutter, fertiliser incorporation (Brushinc); and weeding with a rotary harrow, fertiliser incorporation (Rotaryinc). Nutrient release of surface-applied and incorporated fresh clover (Clover), ensiled clover (Silage), and poultry manure (Poultry) was studied from litterbags subjected to controlled conditions in a 70-day plant-free incubation experiment based on changes in nutrient concentration and dry matter contents in remaining litter; data were collected at 0, 14, 35, 49, and 70 days. Levels of released N and potassium (K) from litterbags were comparable between Poultry and Silage treatments during the 70-day incubation period. Meanwhile, soil mineral N and K levels were similar (or higher) with Clover in the field than with Poultry, indicating that Clover can be substituted for Poultry. However, phosphorus (P) release from litterbags was faster from Poultry than from Clover and Silage in the 70-day incubation experiment, while soil P levels were higher in the field with Poultry, suggesting that Clover should be a preferred fertiliser option for fields with high P levels. Generally, compared to surface-applied fertilisation, incorporation of fertilisers increased N, P, and K release from litterbags in the 70-day incubation experiment, and increased blackcurrant leaf N and K concentrations in the field. Fertiliser types did not affect blackcurrant yield, supporting the replacement of imported poultry manure with a plant-based fertiliser from alley-grown clover.
Published: 19 March 2021
by MDPI
Abstract:
Weeds are often harmful to crop growth due to the competition for space and resources. A field experiment containing four treatments with three replications in a complete randomized design was conducted at Yucheng Comprehensive Experiment Station, Chinese Academy of Sciences since 2008 to assess the impact of shifting from conventional tillage to no-till with crop residue management on weeds and wheat production at the North China Plain. We found that both aboveground weed density and species richness were higher under continuous no-till (NT) than conventional tillage (CT) in the regrowth and stem elongation stage of wheat growth. On the other hand, aboveground weed density in the stage of flowering and filling decreased with crop residue mulching. The density of the soil seed bank in crop residue removal treatments was significantly higher than that of crop residue retention. Besides, either crop residue mulching or incorporating into the soil significantly increased the wheat yield compared with crop residue removal regardless of tillage management. In conclusion, crop residue retention could decrease the weed density and species richness both aboveground and in the soil seed bank and inhibit the growth of broadleaf weeds by the residue layer. Moreover, crop residue retention could improve the wheat yield.
Lucas Rafael Lommez Vaz, Robson Rolland Monticelli Barizon, Adijailton José de Souza,
Published: 6 March 2021
Water, Air, & Soil Pollution, Volume 232, pp 1-11; https://doi.org/10.1007/s11270-021-05074-7

Abstract:
Sugarcane is a major crop in Brazil as well as other tropical areas. The rise of green cane systems that maintain straw on the soil surface after mechanical harvesting alongside extreme precipitation has changed the use and environmental fate of pesticides, mainly herbicides. The goal of this research was to evaluate the effects of straw amounts (0, 7, and 14 t ha−1), soil water contents (10 and 18%, volumetric basis), and herbicide incubation time (0 and 3 days) on the runoff of hexazinone and diuron in green cane systems, under a heavy rainfall event of 120 mm that is becoming more frequent over the decades in tropical areas. A rainfall event of 80 mm h−1 during 1.5 h was simulated over a 1 m2 area, using a rainfall simulator with a structure designed to collect runoff. Herbicides in water runoff were determined by ultra performance liquid chromatography with mass spectrometry (UPLC ESI QTOF/MS), while herbicides attached to sediments were estimated using Kd values. Sugarcane straw on the soil surface decreased water, sediments, and diuron runoffs, but barely affected hexazinone losses. Crop residues cannot prevent runoff of highly soluble molecules, such as hexazinone. Herbicides’ runoffs were much higher in the aqueous phase and at higher soil moisture content. Maintaining 7 t ha−1 of sugarcane straw on the soil surface was enough to mitigate water, sediments, and diuron runoff, but 3-day herbicide incubation did not affect both herbicides runoffs. Diuron and hexazinone are heavily used herbicides that can reach concerning concentrations in the runoff and contaminate surface waters in vulnerable areas if no control measures are taken.
, Meagan E. Schipanski, Angela Tucker, Wilma Trujillo, Johnathon D. Holman, Augustine K. Obour, S.K. Johnson, Joe E. Brummer, Lucas Haag, Steven J. Fonte
Agriculture, Ecosystems & Environment, Volume 313; https://doi.org/10.1016/j.agee.2021.107358

Abstract:
Cover crops are important for soil conservation efforts but can compete with cash crops for limited water in dryland agricultural systems. Grazing cover crops may provide additional income to improve the profitability of cover cropped systems, but the effect of grazing cover crops on soil health remains poorly understood in semi-arid regions. We conducted on-farm research to examine the short-term effects of grazed and un-grazed spring-planted cover crops compared to full summer fallow on soil health metrics and wheat yields across ten no-till, dryland producer fields over two years in eastern Colorado, western Kansas and western Nebraska, USA. Soils were evaluated at cover crop termination following two to three months of growth for differences in a suite of soil physical and chemical properties. Grazed and un-grazed cover crops increased soil aggregation relative to summer fallow by 30−50%. Surface bulk density (0−5 cm) decreased by 4% with un-grazed cover crops, while bulk density under grazed cover crop was similar to fallow. Soil moisture in the top180 cm depth was reduced by 4–22 % with cover crops, with the greatest water depletion occurring below 30 cm, and grazing did not appear to affect soil moisture compared to un-grazed cover crops. Both cover crop treatments reduced wheat yields by roughly 20 %. The short-term improvements to key soil health metrics with cover crops were largely maintained with grazing, indicating the potential for livestock integration as a management option to offset the short-term yield impacts of cover crop moisture use in water-limited environments.
Ernst H. Smit, Johann A. Strauss,
Published: 6 February 2021
Plant and Soil, Volume 462, pp 207-218; https://doi.org/10.1007/s11104-021-04864-6

Abstract:
Cover crops can provide multiple agroecosystem services to crops produced in conservation agriculture systems. South African grain producers in the Mediterranean climate region are reluctant to integrate cover crops in rainfed systems since cover crops replace cash crops leading to financial losses. Using cover crops as fodder can help cover input costs, while providing a range of advantageous services to the cropping system. The aim of this study was to investigate how cover crop mixtures and the utilisation of cover crops affect soil quality, the quality and quantity of the mulch as well as wheat (Triticum aestivum L.) produced in the subsequent year. A two-year study was conducted in the Western Cape Province of South Africa. In Year 1, diverse legume and cereal-based cover crop mixtures were partially grazed, cut and material removed for haymaking, or left unutilised as a mulch. In Year 2, spring wheat (Triticum aestivum L.) was planted to investigate the effects of cover crop mixtures and utilisation method on subsequent spring wheat yield. Cover crops used as hay or for grazing did not affect (P < 0.05) grain yield of wheat that followed in rotation. Legume-based cover crop mixtures increased (P < 0.05) wheat grain protein content regardless of utilisation method. Soil quality and nitrogen content improved (P < 0.05) when cover crops were grazed. Cover cropping can be used by South African grain producers as an important agronomic tactic to improve system productivity and support sustainable intensification of rainfed cropping systems.
, , Blanca Aide Albarrán Contreras, Enrique Andrio Enríquez, Luis Castillo Villaseñor, Fabian Enyanche Velázquez, Helios Escobedo Cruz, Juan Espidio Balbuena, Avelino Espinosa Solorio, Paul Garcia Meza, et al.
Published: 25 January 2021
Land Degradation & Development, Volume 32, pp 2242-2256; https://doi.org/10.1002/ldr.3894

Abstract:
Maize (Zea mays L.) is Mexico’s primary staple food, but the country’s degrading soils and climate variability limit its productivity. Conservation agriculture (CA), a management technique which combines minimal tillage, permanent soil cover and crop diversification, could reduce soil degradation and help improve soil health. There is however a lack of information about the effects of CA on soil health in the diverse agroecological conditions in Mexico. This study reports results of a field trial network established to adapt CA to Mexico’s diverse cropping systems and local conditions. Physicochemical soil health, also referred to as soil quality, was studied in 20 trials in agro‐ecologies ranging from handplanted traditional systems to intensive irrigated systems, initiated between 1991 and 2016. Soil in CA was compared to the local conventional practice, which commonly involves tillage, residue removal and continuous maize production. Across the sites, organic matter and nitrates were higher in the top (0‐5 cm) layer of soil and soil aggregate stability was greater under CA than under conventional practices. For other soil health parameters, such as nutrient content, pH or penetration resistance, the effects of management varied widely across sites and soil types and most were determined more by local soil type than by management. Conservation agriculture increased maize yields at most sites and on average by 0.85 ± 1.80 t ha‐1. Given the significant variation across agro‐ecologies, local adaptive trials are important to assess the effects of CA on soil health and fit the practice to local conditions.
Published: 16 January 2021
by MDPI
Abstract:
Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This study aimed to evaluate the influence of maize and wheat residues, applied in three different quantities (1, the field quantity, 0.5, and 1.5-fold amounts of the field quantity), on the emergence of eight weed species: Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, Setaria pumila, Sonchus oleraceus, and Sorghum halepense. The experiment was conducted over two consecutive years. The results showed that the quantities 1 and 1.5 could suppress seedling emergence by 20 and 44%, respectively, while the quantity 0.5 seems to promote emergence by 22% compared with the control without residues. Weed species showed different responses to crop residues, from C. album showing 56% less emergence to S. halepense showing a 44% higher emergence than the control without residues. Different meteorological conditions in the two-year experiment also exhibited a significant influence on weed species emergence.
Published: 13 January 2021
by MDPI
Abstract:
The effects of earthworm inoculation and cropping systems on upland rice systems were examined over a four-year period in the Highlands of Madagascar. Each year, endogeic earthworms Pontoscolex corethrurus (Rhinodrilidae) were inoculated (EW+) at a density of 75 ind m−2 or were not inoculated (EW0). Inoculation was tested in three cropping systems: conservation agriculture (CA) and traditional tillage with or without residues restitution. Soil and plant properties were measured during the first three years while soil biological properties were assessed at the fourth year. At the end of the experiment, earthworm density was three-fold higher in EW+ than in EW0, demonstrating the success of the inoculation. Earthworm density was more important in CA than in tillage systems. Earthworm inoculation had higher significant effects on soil and plant properties than cropping systems. Earthworm inoculation had positive effects on soil macroaggregation (+43%), aboveground biomass (+27%), rice grain yield (+45%), and N grain amount (+43%). Intensifying earthworm activity in field conditions to meet the challenge of ecological transition is supported by our study.
José Luis Gabriel, Irene García-González, Miguel Quemada, Diana Martin-Lammerding, María Alonso-Ayuso,
Published: 9 January 2021
Abstract:
Replacement of bare fallow in rotations by cover crops is a promising tool to reduce crusting, although the interactions with the soil moisture and the effect of the cover crop species are still not well understood. The objective of this work was to determine how cover crops modify the soil surface response to penetration and their relation with the soil water content. Two winter cover crops, barley (Hordeum vulgare L.) and vetch (Vicia sp. L.), were compared with a bare fallow treatment in a 10-year field experiment in central Spain. Soil resistance to penetration and soil water content were intensively measured (76 sampling dates) at two surface depths, using two types of surface penetrometers. Under the barley cover crop, the number of very dry events was reduced by around 20%, compared to the bare fallow. The soil resistance to penetration was closely related to the surface soil water content (R2 = 0.65) and cover crops affected it through soil moisture modification. In this line, the greater mulch provided by barley cover crop respect to vetch, increased the soil water content prior to main crop seeding, resulting in less resistance to penetration during this critical period. The good performance of barley resulted in a reduction of more than 60% of the soil resistance to penetration between the 3rd and 8th year of the experiment (7.2–2.9 kg cm−2, respectively). Even under bare fallow, soil strength was decreased after ten years with reduced tillage. Therefore, the maintenance of cover crop residues over surface soil together with reduced tillage enhanced the soil surface conditions and steadily reduced the risk of crust formation. Expected enhancement of main-crop germination, water infiltration, soil aeration and erosion mitigation may be attained by cover-cropping in degraded soils.
Published: 21 December 2020
by MDPI
Abstract:
Conservation agriculture has three main pillars, i.e., minimum tillage, permanent soil cover, and crop rotation. Covering the soil surface with plant residues and minimum mechanical soil disturbance can all result from introducing a strip-till one-pass (ST-OP) system. The aim of this study was to determine the impact of the ST-OP technology on the management of plant residues, soil properties, inputs, and emissions related to crop cultivation. We compared the effect of a ST-OP system against conventional tillage (CT) using a plough, and against reduced, non-ploughing tillage (RT). Four field experiments were conducted for evaluating the covering of soil with plant residues of the previous crop, soil loss on a slope exposed to surface soil runoff, soil structure and aggregate stability, occurrence of soil organisms and glomalin content, soil moisture and soil water reserve during plant sowing, labour and fuel inputs, and CO2 emissions. After sowing plants using ST-OP, 62.7–82.0% of plant residues remained on the soil surface, depending on the previous crop and row spacing. As compared with CT, the ST-OP system increased the stability of soil aggregates of 0.25–2.0 mm diameter by 12.7%, glomalin content by 0.08 g·kg−1, weight of earthworms five-fold, bacteria and fungi counts, and moisture content in the soil; meanwhile, it decreased soil loss by 2.57–6.36 t·ha−1 year−1, labour input by 114–152 min·ha−1, fuel consumption by 35.9–45.8 l·ha−1, and CO2 emissions by 98.7–125.9 kg·ha−1. Significant favourable changes, as compared with reduced tillage (RT), were also found with respect to the stability index of aggregates of 2.0–10.0 mm diameter, the number and weight of earthworms, as well as bacteria and fungi counts.
Bikash Kumar,
Published: 9 December 2020
Energy Conversion and Management: X, Volume 10; https://doi.org/10.1016/j.ecmx.2020.100063

Abstract:
The life cycle assessment (LCA) is a well-established tool that has been used to provide data-driven analysis of environmental performances. LCA offers insights via selecting appropriate feedstocks, suitable technology, energy and environmental trade-off to be considered during the policy designing phase. In the present review, LCA analysis of each biomass based biorefinery and its impact assessment has been elaborated. The LCA literature clearly shows that transportation and manufacturing contributes majorly (up to 92.19%) to energy consumption. Further, the major global warming potential (GWP) was contributed by the electricity (86%) consumed in biorefinery industry. Thus, utilizing greener energy sources such as hydroelectricity or bioelectricity for energy and transportation needs can help in minimizing the environmental impacts. Further, development of integrated biorefineries can significantly decrease greenhouse gas (GHG) emissions by 83% as compared to petroleum fuels and can fulfill the requirements for renewable fuel standards (RFS). The generation of multiple products at a single unit can help in adjusting the potential trade-offs and promoting environmentally beneficial processes during the designing phase for future refinery and energy systems. LCA is also a rational tool towards designing process blueprint for bioresources management through multi-products integrated biorefineries. It can be expanded further to cover the techno-economic, social, and health impacts in addition to environmental impacts (integrated sustainability assessment) for future integrated biorefineries and policy decisions.
, T. Diarisso, N. Andrieu, C. Le Page, M. Corbeels
Published: 3 December 2020
Agricultural Systems, Volume 187; https://doi.org/10.1016/j.agsy.2020.102981

Abstract:
In West Africa, new management practices such as conservation agriculture with crop residue mulching can improve crop yields for individual farmers. However, in a context of complex social interactions between farmers, the introduction of such practices can also lead to conflicts between private interests and communal use of resources, for example the free grazing of crop residues. The objective of this paper was to assess ex-ante the impacts of the practice of crop residue mulching on crop productivity in a village of central Burkina Faso using an agent-based model, AMBAWA, that simulates the flows of biomass and nutrients between crop and livestock systems at the village scale. The model considers the interactions between four types of farmers that were identified in the study site: subsistence-oriented crop farmers, market-oriented crop farmers, agro-pastoralists and pastoralists. The model simulated increased cattle migration outside the village due to increased crop residue scarcity during the dry season with increased proportions of cropland under the practice of conservation agriculture, decreasing the manure availability at village scale. Consequently, the assumed direct yield increases due to soil moisture conservation as a result of mulching did not compensate for the yield losses resulting from lesser amounts of manure available. This effect was felt most strongly by farmers who own relatively large numbers of cattle (agro-pastoralists and pastoralists). The total maize production at village level depended more on the proportion of cropping land that was available for grazing by cattle, and thus not mulched, than on a possible direct effect of mulching on yield per se. The AMBAWA model can support discussion among stakeholders (farmers, traditional and administrative authorities) who are involved in the private and communal management of crop residues and other biomass resources, in order to co-design effective arrangements and practices for their sustainable use.
, Hélène Frey, Florian Celette, Léo Garcia, Karim Barkaoui, Laure Hossard, Audrey Naulleau, Raphaël Métral, Christian Gary,
Published: 27 November 2020
European Journal of Agronomy, Volume 123; https://doi.org/10.1016/j.eja.2020.126191

Abstract:
‘Service plants’ include spontaneous vegetation or sown species of cover crops associated with perennial crops in the rows or inter-rows with a high potential to provide ecosystem functions and services. In vineyards, service plants target specific services depending on the management strategy implemented by the winegrower, including the plant species, the surface covered, the plant growth control and destruction date. Understanding the management strategies linked to their associated target services at the regional scale is necessary to better help winegrowers, advisers and policy makers regarding an adapted use of service plants. To do this, we conducted a survey in 2016 among 334 winegrowers in Languedoc-Roussillon region in France, enquiring about their service plant management practices during the season 2014–2015. Given the diversity of the strategies of service plant management, we proposed a typology analyzing their spatial and temporal dimensions. Further, we present a Coverage Index (CI), which combines both temporal and spatial dimensions of the service plant management strategies. We conducted a multiple components analysis and clustering to create a vineyard typology and applied linear models to find correlations between the CI and specific vineyard characteristics. Three quarters of interviewed winegrowers sowed or maintained service plants in their vineyards; 41 % used a winter service plant strategy; 8.4 % a semi-permanent and 27.3 % a permanent service plant strategy. The preferred surface coverage strategy was full surface during grapevine dormancy and its reduction to half of the inter-rows after grapevine budburst. However, the diversity of surface coverage strategies during the grapevine vegetative period was remarkable. Lower water resources and specific soil characteristics were not linked to the service plant management strategies. Higher CI was associated with vineyards presenting quality labels (PDO and Organic), independent winemaking and lower target yields, showing that the added value of producing high quality wine plays an important role when implementing service plants in vineyards. Overall, our study showed: i) the popularity of spontaneous service plant strategies; ii) the spatial and temporal diversity of service plant management strategies and iii) the utility of the CI to study the implementation of service plants and to understand the motivations and constraints of their use.
Hao Wang, Shulan Wang, Qi Yu, Yujiao Zhang, Rui Wang, , Xiaoli Wang
Published: 24 November 2020
Land Degradation & Development, Volume 32, pp 1833-1843; https://doi.org/10.1002/ldr.3836

Abstract:
In residue returned farming, plowing and zero tillage rotation may regulate soil physicochemical properties and help erodible productivity; however, the soil physicochemical property and soil productivity response to plowing and zero tillage rotation remains unclear. The present study evaluated the effects of plowing and zero tillage rotation on soil physicochemical properties and productivity based on an 11‐year experiment (2007–2018) on a typical erodible area of the Loess Plateau. Three tillage methods were included: plowing and zero tillage rotation with one‐year plowing tillage and one‐year zero tillage (PZT), plowing tillage with moldboard plow (PT), and zero tillage (ZT); crop residue was returned in all treatments. After 11 years test, the PZT method showed significantly lower soil water storage in key maize growth stages, less soil organic carbon (SOC) and total nitrogen (N) storage (0–10 cm), and poorer soil structure stability (0–10 cm) when compared with ZT. However, PZT showed significantly higher SOC and N storage (4.5%, 6.5% and 16.3%, 8.6%, respectively) in the 10–20 cm and 20–40 cm soil layers, compared with ZT. In addition, when compared with ZT and PT, PZT significantly decreased soil penetration resistance in 0–10 cm, 10–20 cm, and 20–40 cm soil depths, and significantly increased yield of maize by 10.9% and 7.8%, respectively, and of wheat by 11.2% and 9.8%, respectively. This study highlights that combining plowing and zero tillage with returned crop residue changed soil physicochemical properties and can provide an effective method to improve soil productivity in an erodible field. This article is protected by copyright. All rights reserved.
Shuxia Jia, , Shixiu Zhang, Xuewen Chen, Neil B. McLaughlin, Bingjie Sun, Xiaoping Zhang,
Published: 19 November 2020
Abstract:
Selecting appropriate soil management practices (e.g. tillage treatments) provides an opportunity to sequester soil carbon (C), improve soil health, and achieve ample food production in an agricultural system. The responses of soil CO2 emission, soil microbial community, and crop yield to precipitation are crucial for assessing sustainability of conservation tillage. Soil CO2 flux, soil microbial phospholipid fatty acid (PLFA) contents and crop yield were measured in a long-term (15 years) tillage study in the Northeast of China under a normal year in 2013 and natural drought year in 2015. The results showed in a normal year with precipitation similar to the 30-year mean, soil temperatures at 5, 10 and 20 cm in June under mouldboard plough (MP) were higher by 0.9, 1.0 and 1.1 °C, respectively, than under no-tillage (NT); soil water content in the top 22 cm under MP was significantly lower than that under NT in 04 June and 31 July; and MP significantly increased maize (Zea mays L.) yield and C emission efficiency (the ratio of yield to annual soil CO2 emission) by 22% and 25%, respectively. In a dry year (2015), soil temperatures at 5, 10, and 20 cm in June and July under MP were higher by 2.0, 1.8 and 1.7 °C than under NT, respectively; soil water content in the top 22 cm under MP was significantly lower than under NT by 28% in July; moreover, MP significantly decreased maize yield and C emission efficiency by 47% and 63%, respectively. However, there were no significant differences in annual soil CO2 emission between NT and MP in the normal and dry years. Compared with MP, NT significantly increased soil microbial PLFA contents in pre-planting (April) and late segments of the growing season (August-September) of a normal year, but significantly increased soil microbial PLFAs content in pre-planting and all of early, mid and late segments of the growing season in a dry year. Structural equation modelling (SEM) revealed that soil water content, temperature, bacteria and fungi directly contributed to C emission efficiency. Tillage was indirectly associated with C emission efficiency through soil water content, temperature, soil fungi and bacteria. These results suggested that the higher maize yield and C emission efficiency under NT compared to CT were related to improved soil water content and soil microbial PLFA contents and the lower soil temperature in a dry year. Our results suggested that NT (a subset of conservation tillage) might be a positive adaptation strategy to cope with drought under monoculture maize in northeast China.
Published: 5 September 2020
by MDPI
Abstract:
The benefits of conservation practices increased the interest of farmers in the cultivation of cover crops (CCs). This review aims to present and analyze the state of the art on the cultivation of legume CCs, including their importance in protecting crops against weeds, as well as their effects on organic matter and nitrogen content in the soil, physical and biological properties of the soil, and its erosion. The multi-purpose character of legume CCs is visible in their positive effect on reducing weed infestation, but also on the soil: reducing its compaction and erosion, improving its structural and hydraulic properties, increasing the content of organic matter and activity of soil microorganisms, or increasing its nitrogen content due to symbiotic N2 fixing. This review demonstrates that a wider use of legume CCs in organic farming is needed. The benefits of legume CCs for successive crops in these cultivation conditions, both in terms of inhibiting weed populations and improving fertility and soil properties, also need to be identified. Further research is also needed to determine the potential impact of legume CCs on the improvement of the quality of degraded soils, or those with less favorable physicochemical properties.
, Bhupinder Pal Singh, Naveen Gupta
No-till Farming Systems for Sustainable Agriculture pp 33-45; https://doi.org/10.1007/978-3-030-46409-7_3

Abstract:
No-till (NT) is a farming system where crop is directly sown in untilled soil. The NT system coupled with crop residues retained on soil surface helps to increase soil organic matter, conserve soil moisture, improve erosion control, enhance agricultural sustainability, and reduced labor requirements. However, the influence of residue management on crop production in NT systems is complex and variable, due to both direct and indirect effects and their interactions in different climatic conditions. Soil organic carbon (SOC), a key indicator of soil health, increases on the soil surface under NT system, although there is often no change or a loss of SOC in deeper soil layers. This review has identified the key technological challenges in adopting NT systems and the strategies to overcome those challenges that relate to agronomic management, packaging, standardization, and adoption of farm machinery for seeding. The major strategies to overcome these challenges are: (i) farmers’ participatory research through on-farm trials, including adaptive research; (ii) policy support for capacity building; and (iii) the manufacture of local machinery for implementation of NT technology in a region.
Se-In Park, Hye In Yang, Hyun-Jin Park, Bo-Seong Seo, Young-Jae Jeong, Sang-Sun Lim, Jin-Hyeob Kwak, Han-Yong Kim, Kwang-Sik Yoon, Sang-Mo Lee, et al.
Published: 1 September 2020
Science of The Total Environment, Volume 753; https://doi.org/10.1016/j.scitotenv.2020.142053

Abstract:
Soil surface with crop residue is effective in reducing soil erosion and carbon (C), nitrogen (N), and phosphorus (P) losses from sloping fields. However, there is a high possibility that surface cover increases export of dissolved organic C (DOC) though relevant field studies under natural rainfall are lacking. In this study, the effects of surface cover with rice (Oryza sativa L.) straw on soil and CNP losses in both dissolved and sediment-bound forms from maize (Zea mays L.) fields were investigated under two fertilization levels (standard and double) × two types of runoff experiments (natural rainfall and artificial irrigation). Changes in soil properties including moisture, temperature, nutrients, and C concentration as well as maize yield were also examined. Surface cover decreased soil and total CNP losses by up to 82% across the experimental plots with some exceptions. However, surface cover increased DOC export in both natural (by 68–82% in total across all events) and artificial (by 3–4 fold) runoff, suggesting that crop residue cover may act as a DOC pollution source of water bodies. The contribution of rice straw to DOC, which was calculated using the δ13C of DOC from covered plots (−24.1 to −28.0‰) and control plots (−19.6 to −25.1‰), was 52.5–95.8%. The concentrations of K2SO4-extractable and microbial biomass C of the soils did not differ between covered and control plots, suggesting that DOC produced from rice straw was not incorporated into the soils, but rather, was washed out with surface runoff in this study. Surface cover increased maize growth and yield, particularly in double fertilization plots, through improved soil moisture, temperature, and nutrient conditions. To take full advantage of surface cover with crop residue, a further study on reducing DOC loss from crop residue needs to be conducted.
Anna Maria Visscher, , Katherin Meza, Ron G.M de Goede, Amador A. Valverde, Raul Ccanto, Edgar Olivera, Maria Scurrah,
Agriculture, Ecosystems & Environment, Volume 303; https://doi.org/10.1016/j.agee.2020.107107

Abstract:
Intensified rotations and increased reliance on agrochemical inputs in many parts of the Andean highlands generate concern for soil health, biodiversity, and key ecosystem functions that are essential for maintaining agricultural productivity and the well-being of smallholder communities throughout the region. Improved management of perennial vegetation within field margins represents a promising option currently being explored in many Andean communities, with the potential to better design these field margins to support multiple ecosystem services (ES). In this study we examined the effect of two types of common woody perennial field margins (eucalyptus vs. alder) on crop production and other soil-based ES at variable distances from the field edge. Sampling was conducted in twenty potato fields, ten with borders dominated by alder trees (Alnus acuminata) and another ten with eucalyptus (Eucalyptus globulus). Within each field, transects (∼10 m) were established with six sampling points extending from the perennial field margins towards the center of the production field. At each point, a suite of ES was assessed including: nutrient provision (based on levels of SOM, pH, P, K, and N in the soil), biodiversity maintenance (ground vegetation and soil macrofauna), erosion control (infiltration, aggregation, bulk density), bio-control (occurrence of common crop pests/pathogens and predators) and crop production (potato yields and quality). The provision of ES was generally found to be higher in the field margins than in the arable fields. The dominant tree species in the field margin was also important, such that fields bordered by alder trees showed higher SOM, macrofauna diversity and aggregate stability compared to those bordered by eucalyptus trees. Fields bordered by eucalyptus trees showed higher values for overall vegetation diversity, pH and available phosphorus. While potato yields did not differ between fields bordered by alder vs. eucalyptus, potato pest pressure was higher in fields bordered by eucalyptus trees. Our findings suggest that improved management of perennial field margins can enhance the provision of multiple ES in agricultural landscapes of the Peruvian highlands.
Alpha Bocar Baldé, Eric Scopel, François Affholder, Fernando Antonio Macena Da Silva, Jacques Wery,
Experimental Agriculture, Volume 56, pp 561-573; https://doi.org/10.1017/s0014479720000150

Abstract:
Relay intercropping of maize with fodder crops is a promising option for sustainable intensification of dairy small-scale farms in the Cerrado of Brazil. Twenty-six intercropping trials were conducted on farmers’ fields with the following experimental treatments: sole maize crop cropping (MS), maize-Brachiaria intercropping (MB) and maize-pigeon pea intercropping (MP). The trials were managed by the farmers, i.e. choice of conventional tillage (CT) versus no-tillage (NT), sowing dates, fertilization and weed control. Maize grain yield varied strongly across the farmer fields, from 100 to 5900 kg ha−1 in the MS treatment, 500 to 6900 kg ha−1 in MP and 300 to 5500 kg ha−1 in MB. Intercropping did not significantly affect maize grain yields under NT, but yields were reduced under CT in one out of two seasons. Maize yields in the intercropped systems were also higher under NT than CT. Total biomass productivity was significantly higher in the maize-fodder than in the sole maize system. An increased interval between sowing of maize and fodder crop significantly reduced the fodder crop biomass. Relay intercropping, especially in combination with NT, is a promising option if crop calendars and fertilization are properly managed by farmers to reduce interspecific competition between the maize and fodder crop.
Published: 16 July 2020
Nature Food, Volume 1, pp 447-454; https://doi.org/10.1038/s43016-020-0114-x

Abstract:
Conservation agriculture (CA) has become a dominant paradigm in scientific and policy thinking about the sustainable intensification of food production in sub-Saharan Africa. Yet claims that CA leads to increasing crop yields in African smallholder farming systems remain controversial. Through a meta-analysis of 933 observations from 16 different countries in sub-Saharan African studies, we show that average yields under CA are only slightly higher than those of conventional tillage systems (3.7% for six major crop species and 4.0% for maize). Larger yield responses for maize result from mulching and crop rotations/intercropping. When CA principles are implemented concomitantly, maize yield increases by 8.4%. The largest yield benefits from CA occur in combination with low rainfall and herbicides. We conclude that although CA may bring soil conservation benefits, it is not a technology for African smallholder farmers to overcome low crop productivity and food insecurity in the short term.
, , , Eric Scopel, Fernando Antônio Macena Da Silva,
International Journal of Agricultural Sustainability, Volume 18, pp 410-426; https://doi.org/10.1080/14735903.2020.1788253

Abstract:
Conservation agriculture (CA) is recognized as a promising crop management strategy for sustainable agricultural intensification. The objective of this study was to evaluate CA cropping systems for rainfed maize as an alternative to the traditional tillage-based cropping systems (CT) in the context of family farms, using a multi-criteria model that represents the point of view of farmers. Farmers considered several aspects for evaluating the cropping systems, thatwere systematized in the model through five criteria (with sub-criteria): (a) costs; (b) yield; (c) labour; (d) human health and environment; and (e) production risks. CA did not differ from CT for the ‘costs’ criterion but was superior for the ‘yield’ and ‘labour’ criteria. In contrast, CT obtained better ratings for the criteria ‘human health and environment’ and ‘production risks’. Considering all criteria, CA was better appraised than CT. However, a new local policy measure that subsidizes the hiring of mechanized tillage services overturns this outcome, indicating the importance of exogenous factors. Overall, the participatory processes in building the model allowed us to better understand the reasons of adoption or non-adoption of CA by small-scale farmers in the tropics.
Published: 18 June 2020
by MDPI
Abstract:
In conservation agriculture, slugs are considered significant pests and their monitoring is a key option in the integrated pest management framework. Together with molluscicide applications, predators such as ground beetles can offer a tool for slug control in the field. Through the evaluation of slug and ground beetle monitoring strategies, this work compared their presence in conventional and conservation agricultural plots. The invasive Deroceras invadens was the dominant slug species to occur in all sampling periods. Among Carabidae, Poecilus cupreus and Pterostichus melas were the most abundant species, and Bembidion spp., Brachinus spp., and Harpalus spp. were also common. Beer-baited pitfall traps, whatever their alcoholic content, caught more slugs and ground beetles than wooden boards used as shelters. Slugs were more abundant in conventional plots than in conservation plots, possibly due to the lower presence of natural enemies such as ground beetles. Despite possible impacts on Carabidae, beer-baited pitfall traps should be considered a useful tool for slug monitoring and for the planning of molluscicide applications. Soil management such as minimum- or no-tillage and the presence of cover crops are important elements influencing both slug and ground beetle presence, possibly playing a key role in the maintenance of natural enemy populations.
Chong-Liang Luo, Xiao-Feng Zhang, Hai-Xia Duan, David M. Mburu, Hong-Xu Ren, Levis Kavagi, Run-Zi Dai,
Science of The Total Environment, Volume 738; https://doi.org/10.1016/j.scitotenv.2020.139808

Abstract:
The extreme climate events such as El Nino seriously threaten crop production and agro-ecological sustainability because of the aggravated environmental stresses worldwide, particularly in sub-Saharan Africa. To address this issue, we investigated the effects of dual plastic film and straw mulching in ridge-furrow (RF) system on wheat productivity, soil carbon and nitrogen stocks in a semiarid area in Kenya from 2015 to 2017. The experimental site represents a typical semiarid continental monsoon climate, and soil type is chromic vertisols. Field experiment with randomized block design consisted of six RF treatments as follows: 1) dual black plastic film and straw mulching (RFbS), 2) dual transparent plastic film and straw mulching (RFtS), 3) sole black plastic film mulching (RFb), 4) sole transparent plastic mulching RF (RFt), 5) sole straw mulching (RFS) and 6) no mulching (CK). The results indicated that seasonal dynamics of rainfall and air temperature fit in with the weather type of El Nino over four growing seasons. RFbS, RFtS, RFb and RFt significantly increased soil water storage (SWS), topsoil temperature, aboveground biomass, grain yield and water use efficiency across four growing seasons (p < 0.05) as compared with CK. Among all the treatments, RFbS and RFtS achieved the greatest SWS, AgB, grain yield and WUE, owing to improved soil hydro-thermal status in both treatments. Critically, RFbS and RFtS significantly improved soil organic carbon and total nitrogen, soil bulk density and the C:N ratio following four growing seasons, comparing with other treatments (p < 0.05). Besides, RFbS and RFtS gave the highest economic returns among all treatments. For the first time, we found that dual plastic film and straw mulching could serve as a sustainable land management to boost wheat productivity and improve soil quality under El Nino in semiarid areas of SSA.
, Matthew D. Ruark, Kevin B. Shelley
Agronomy for Sustainable Development, Volume 40, pp 1-12; https://doi.org/10.1007/s13593-020-00615-6

Abstract:
Winter rye (Secale cereale L.) is a popular cover crop in North Central United States for preventing soil erosion and nutrient losses, among other agronomic and ecosystem benefits. Winter rye can also be a high-quality spring forage option when double-cropped with corn silage (Zea mays L.), thus adding diversity to monocrop rotations. However, these sustainability-promoting benefits have potential trade-offs including soil nutrient immobilization and decreased corn yields. We hypothesized that winter rye would promote sustainable intensification of corn silage, as substantiated by decreased nitrogen budget and soil nitrate without yield loss. We also predicted that winter rye double-cropped and harvested as a forage would maintain total production (corn silage + rye harvest) compared to corn silage alone. This five-season study is representative of continuous corn silage systems in North Central United States, and Wisconsin specifically, distinguished by fall liquid dairy manure applications. Corn was planted after rye termination or harvest, and varying rates of nitrogen were applied to corn. As predicted, rye cover reduced preplant soil nitrate without affecting corn silage yield. Rye harvested as a forage crop reduced preplant and in-season soil nitrate, and total production equaled or exceeded corn silage yields without rye, despite a 13% decrease in corn silage yield. The 5-year nitrogen balance demonstrated almost 40% reduction in excess nitrogen in the rye forage system. This novel study demonstrated no cumulative or single-year agronomic limitations to winter rye implementation in manured, corn silage systems characteristic of North Central United States over a range of seasonal weather conditions. Furthermore, the dual use of rye as a cover crop conservation practice or harvested as a forage double-crop makes it agronomically advantageous and demonstrate potential for sustainable intensification in this system. This research is the first to show that sustainable intensification through double cropping dairy-based systems can increase high-quality biomass production while reducing nitrogen losses to the environment.
Published: 21 March 2020
by MDPI
Abstract:
An increased nitrogen (N) supply was proposed to avoid grain yield (GY) reductions and successfully implement conservation agriculture (CA). We investigated interactions effects of tillage system and N supply on winter wheat (Triticum aestivum L.) at two sites in the Swiss midlands with no (0 kg N ha−1) and high (150–160 kg N ha−1) N supply using 15N-labelled ammonium nitrate in selected treatments. Wheat’s GY, yield components, N related traits and soil mineral N content (Nmin) under conventional tillage (CT), minimum tillage (MT), and no-tillage (NT) were studied following two preceding crops: oilseed rape (Brassica napus L.) and maize (Zea mays L.). Wheat after oilseed rape had significantly higher GY and biomass than after maize while a yield decrease under NT compared with CT and MT was observed regardless of N supply level. Differences in soil Nmin among tillage systems were seldom found and were inconsistent. No differences in 15N fertilizer recovery were found between NT and CT while residual Nmin after harvest was lower under NT than CT or MT. In conclusion, we did not found consistent reductions in soil N availability and N uptake under NT that would justify an increased N supply for wheat under CA.
Zhaoqiang Jin, , Li Zhang, Hongyan Liu, Shaobing Peng,
Published: 4 March 2020
Food and Energy Security, Volume 9; https://doi.org/10.1002/fes3.200

Abstract:
The rice–wheat rotation model of crop planting is widely used globally, and worldwide, straw returning is the main method of crop straw treatment. However, the straw return method commonly used in the modern rice–wheat rotation system has many adverse effects on the levels and improvement of soil fertility and crop yield, and there is no systematic theory of rice and wheat straw returning to use as a guide. In this paper, we concluded that: in the rice–wheat rotation system, returning 1,500–4,500 kg/ha of rice straw and 2,250–6,750 kg/ha of wheat straw to the field helps increase the organic carbon content and quality of the soil and promotes high annual yields; conventional mixing of straw into the field can increase the organic carbon content of the soil in a short time; long‐term use of concentrated ditch‐buried straw return has obvious advantages over other straw returning methods in increasing the accumulation of soil organic carbon; the combination of little or no tillage plus straw returning helps increase the content and quality of organic carbon in soil; and when the soil water content is 15%–22.5%, it is the most conducive to the accumulation of soil organic carbon. In addition, we also provide relevant suggestions for future research directions on straw returning via systematic analyses and thought processes.
Published: 24 December 2019
Cahiers Agricultures, Volume 28; https://doi.org/10.1051/cagri/2019031

Abstract:
En système d’agriculture de conservation, les résidus de cultures ne sont plus brassés dans un volume de sol labouré mais maintenus à la surface des sols ou partiellement enfouis. Leur présence contribue à la durabilité de ces systèmes par le maintien des équilibres agronomiques et environnementaux qu’ils induisent. Dans ce contexte, la connaissance de l’évolution de leur quantité à la surface d’un sol, de la récolte au semis de la culture suivante, devient un enjeu important de gestion des sols. Plusieurs auteurs ont établi une relation entre le taux de couverture du sol (TC) et la biomasse, propre à chaque espèce végétale, à partir d’un formalisme développé par Grégory (1982). Les objectifs de ce travail sont de tester sa validité dans le contexte pédoclimatique de la région Grand-Est (France), après récolte et au cours du processus de décomposition des résidus. Ce travail a été réalisé sur des exploitations pratiquant l’agriculture de conservation depuis plusieurs années. Les résidus ont été broyés lors de la récolte ou d’une opération spécifique. Les données de biomasse ont été collectées à l’aide de cadres de 0,5 m × 0,5 m, tandis que la couverture du sol a été étudiée à l’aide de photographies numériques. Le taux de couverture du sol a été calculé à l’aide d’un logiciel d’analyse d’images. Ce travail compare également deux périodes de mesure : en sortie d’hiver, plusieurs mois après la récolte, et juste après la récolte estivale. Les résultats montrent une très bonne correspondance entre le TC et la biomasse mesurée au sol, toutes espèces et période de mesures confondues, moyennant l’ajout d’un paramètre au formalisme de Grégory (1982). L’intégration de la variabilité spatiale au sol permet de proposer l’emploi d’un ajustement linéaire unique qui simplifie la prédiction du TC du sol ou « la prédiction » de la quantité de biomasse.
Published: 20 December 2019
by MDPI
Abstract:
Management practices that promote dual-purpose use of cover crops as forage and soil cover can encourage adoption in mixed smallholder (SH) farming systems. This study investigated the feasibility of dual-purpose use of forage sorghum (Sorghum bicolor x Sorghum bicolor var. sudanense) by testing the effects of clipping frequency and nitrogen (N) topdressing on the root biomass, crude protein (CP), acid detergent (ADF), and neutral detergent fiber (NDF) in the greenhouse and vegetative biomass on the experimental farm station. Four levels of clipping were tested: not clipped (C1), clipped once (C2), twice (C3), and thrice (C4). Nitrogen topdressing had two levels: with (N1) and without (N0) recommended supplementary N. Results show that absence of N topdressing significantly (p < 0.05) increased root biomass in C2, while increasing clipping frequency significantly (p < 0.001) decreased root biomass. During the growing period, N topdressing significantly (p < 0.001) increased CP content in C3 and C4 and NDF (p < 0.01) content in C4. At the termination stage, there was a significant interaction between clipping frequency and N topdressing on the biomass yield obtained in both 2016–2017 (p < 0.05) and 2017–2018 (p < 0.001), respectively. Clipping twice and N topdressing emerged as the best management practice for the dual-purpose of soil cover and livestock feed.
, Brian Nault, Bryan Brown
Entomologia Experimentalis et Applicata, Volume 168, pp 7-27; https://doi.org/10.1111/eea.12863

Abstract:
Decline in soil health is a serious worldwide problem that decreases complexity and stability of agricultural ecosystems, commonly making them more prone to outbreaks of herbivorous insect pests. Potato (Solanum tuberosum L., Solanaceae) and onion (Allium cepa L., Amaryllidaceae) production is currently characterized by high soil disturbance and heavy reliance on synthetic inputs, including insecticides. Evidence suggests that adopting soil conservation techniques often (but not always) increases mortality and decreases reproductive output for the major insect pests of these important vegetable crops. Known mechanisms responsible for such an effect include increases in density and activity of natural enemy populations, enhanced plant defenses, and modified physical characteristics of respective agricultural habitats. However, most research efforts focused on mulches and organic soil amendments, with additional research needed on elucidating effects and their mechanisms for conservation tillage, cover crops, and arbuscular mycorrhizae.
Sambo Pheap, Clara Lefèvre, , Vira Leng, Stéphane Boulakia, Ra Koy, Lyda Hok, Pascal Lienhard, Alain Brauman, Florent Tivet
Published: 1 November 2019
Soil and Tillage Research, Volume 194; https://doi.org/10.1016/j.still.2019.104349

Kathrin Grahmann, Valentina Rubio Dellepiane, ,
Agriculture, Ecosystems & Environment, Volume 287; https://doi.org/10.1016/j.agee.2019.106710

Abstract:
Continuous agriculture (CA) has led to sustainability problems linked with production decreases, environmental contamination, crop failure and soil degradation in many regions of the world. Crop-pasture rotations (CPR) are management alternatives that contribute to environmental sustainability and productive diversification. Long-term experiments (LTE) play a major role in evaluations of the impact of different management practices on soil quality. However, the results can be misleading if the data are not adequately analyzed. A unique dataset of annual soil samples from a 55-year-old LTE was used 1) to evaluate the effects of a crop-pasture rotation on soil quality and crop productivity and 2) to provide robust statistical models to measure long-term changes in chemical soil quality parameters. Treatments were seven rotations, including CA or CPR with different proportions of pasture in the system (33%, 50%, or 66%). Soil organic carbon (SOC), total nitrogen (Ntot), exchangeable potassium (K) and soil pH have been determined annually since 1964, and the cumulative treatment effects were analyzed. Correlation structures showing the variance heterogeneity for the study years were tested for each parameter and condition. The longer the duration was of the pasture in the rotation, the slower the degradation was in the chemical soil quality. The CPR made a key contribution to sustainable agricultural diversification and intensification, leading to 30% higher crop yields and 19% and 14% greater SOC and Ntot concentrations, respectively, compared with CA. This LTE played a major role in the identification of strategies to increase soil fertility with diversified crop rotations through pasture integration, and statistically robust results were obtained that demonstrate the significance of frequent soil surveying over the long run.
Published: 17 October 2019
by MDPI
Abstract:
Weed suppression is a potential benefit of cover crop mixtures, as species diversity may allow for combining early and late-season competition with weeds. Here, we studied if this is possible for only-legume mixtures containing species with different growth rates, by testing two legumes, alsike clover (AC; Trifolium hybridum L.) and black medic (BM; Medicago lupulina L.) in two field trials sown in 2016 and 2017. Five AC:BM ratios (100:0, 67:33, 50:50, 33:67, and 0:100) were grown at three densities (50%, 100%, and 150% of recommended seed density). Cover crop and weed aboveground biomass (CCB and WB, respectively) were harvested three times, after establishment in spring (H1), in summer (H2), and in autumn after mulching (H3). Compared to fallow plots, all monocultures and mixtures showed early-season weed suppression in terms of biomass production and more efficiency over time with an average reduction of 42%, 52%, and 96% in 2016, and 39%, 55%, and 89% in 2017 at H1, H2, and H3, respectively. Out of 54 mixture treatments, only eight mixtures showed stronger weed suppression than monocultures. Mixtures reduced WB by 28%, as an average value, in 2017 compared to the respective monocultures, but not significantly in 2016, indicating that the crop diversity effect on weeds was dependent on the growing environment. Weed suppression was significantly higher at 100% and 150% seed density than 50%, but no significant differences were determined between 100% and 150% seed density. After mulching, no density effect was observed on CCB and WB. In conclusion, AC and BM can be used as a keystone species on weed suppression for sustainable agriculture as they possess plasticity to suppress weeds when higher biomass productivity is limited by environmental conditions. However, their diversity effects are time and condition dependent. Appropriate seed density and mulching can successfully be employed in weed management, but seed density may not have an effect after mulching.
, , Else K. Bünemann, , , Paul Mäder, , Jean‐Claude Walser, Ron G. M. De Goede
Published: 16 October 2019
Molecular Ecology, Volume 28, pp 4987-5005; https://doi.org/10.1111/mec.15270

Abstract:
Soil nematode communities and food web indices can inform about the complexity, nutrient flows and decomposition pathways of soil food webs, reflecting soil quality. Relative abundance of nematode feeding and life‐history groups are used for calculating food web indices, i.e. maturity index (MI), enrichment index (EI), structure index (SI) and channel index (CI). Molecular methods to study nematode communities potentially offer advantages compared to traditional methods in terms of resolution, throughput, cost and time. In spite of such advantages, molecular data have not often been adopted so far to assess the effects of soil management on nematode communities and to calculate these food web indices. Here, we used high‐throughput amplicon sequencing to investigate the effects of tillage (conventional vs reduced) and organic matter addition (low vs high) on nematode communities and food web indices in ten European long‐term field experiments and we assessed the relationship between nematode communities and soil parameters. We found that nematode communities were more strongly affected by tillage than by organic matter addition. Compared to conventional tillage, reduced tillage increased nematode diversity (23% higher Shannon diversity index), nematode community stability (12% higher MI), structure (24% higher SI), and the fungal decomposition channel (59% higher CI), and also the number of herbivorous nematodes (70% higher). Total and labile organic carbon, available K and microbial parameters explained nematode community structure. Our findings show that nematode communities are sensitive indicators of soil quality and that molecular profiling of nematode communities has the potential to reveal the effects of soil management on soil quality.
, David Dent
Published: 1 September 2019
Farming the Black Earth pp 125-149; https://doi.org/10.1007/978-3-030-22533-9_6

Abstract:
Tillage is controversial but for generation after generation there was no debate: farmers ploughed as their forbears had ploughed, only more thoroughly. Pros: weeds and pests are controlled by breaking their life cycle—briefly; ploughing breaks up a crusted surface and compacted topsoil—briefly; creates a seed bed; and releases plant nutrients through mineralization of soil organic matter—this can also be a disadvantage. Cons: removal of surface cover and loss of soil structure renders the soil vulnerable to erosion; the habitat and life cycles of earthworms, mycorrhiza and myriad other beneficial soil organisms are disrupted; it compacts the plough sole and interferes with both drainage and up-flux of water; and it is costly in fuel and labour. On the Typical chernozem of the Bălţi Steppe, long-term field trials on different kinds of tillage, excluding zero tillage, show no difference in soil water stocks in spring, bulk density or crop yields; but loss of soil organic matter was 1.6 times greater under the mouldboard plough compared with disking. Following the Dust Bowl in the 1930s, measures were developed to control erosive runoff: contour terraces, grassed waterways and the like. They have never been popular because the initial cost and continual upkeep are not recouped. Moreover, they don’t deal with the root cause; they allow business as usual but, when terraces are breached, the result is worse than before. The prime purpose of ploughing is to kill weeds; desiccant herbicides made zero tillage a viable proposition and, since the 1960s, it has been adopted by farmers over 14% of the world’s cropland. It offers control of soil erosion, a simpler operation to manage, less outlay on machinery, more planting days, greater tolerance of drought, generally higher yields and, not least, a reduction of man-hours by nearly 70%. Growing out of these farmers‘ experience, Conservation Agriculture (CA) encompasses no mechanical soil disturbance; continuous ground cover by crops or crop residues; and crop diversification through rotations or associations of crops that control weeds, pests and disease. The new paradigm works almost everywhere for the simple reason that it eliminates destructive disturbance of the soil and daily attack by sun, wind and rain. But the first law of CA, often ignored, is remove all physical and chemical limitations before adopting no-till; plough pans need to be broken up by deep cultivation. Retention of crop residues protects the surface and fuels life in the soil which, given half a chance, is self-sustaining; and ground cover of 70% usually eliminates soil erosion. Rotations should include perennial grasses and legumes for biological fixation of nitrogen to generate enough biomass to regenerate the soil. Excessive usage of pesticides under zero tillage is a myth—CA farmers use less and fewer chemicals than conventional farmers; but precaution demands an alternative. Transition to CA is a complex...
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