Conservation Agriculture Practices Research Articles

Changes in microbial physiology and carbon-use efficiency upon improving soil habitat conditions in conservation farming systems

The interplay between soil microbial anabolism and metabolism has recently been postulated as an important lever for carbon sequestration in soils. Theoretical considerations suggest that high microbial growth rates and a high carbon-use efficiency (CUE) are associated with increased soil organic carbon (SOC) build-up in arable soils. Nature-oriented conservation agricultural practices are believed to facilitate this microbial-driven process of SOC accrual; a practical validation of this postulation is however missing. Against this background, we evaluated the effect of agricultural management and site-specific soil chemical and physical properties on microbial physiology (i.e., respiration, bacterial and fungal growth rates, and microbial biomass turnover) and CUE by an on-farm comparison of conventional farming, conservation farming and unmanaged reference soil systems (i.e., adjacent field margins) at twenty-one sites across three soil depths. We show that a change in agricultural management towards soil health regeneration has a significant impact on microbial physiology. Bacterial growth, respiration and microbial biomass turnover increased from conventional farming towards conservation farming systems to reference soils. The opposite trend however was found for fungal growth and microbial CUE, with highest values observed in conventional farming systems. This clearly contradicts the prevailing idea that higher microbial CUE in conservation farming systems may be associated with higher SOC contents. Our results further show that soil physical and chemical parameters such as soil pH, texture and dissolved carbon compounds strongly predict microbial CUE. In line with these results, functional pore domains showed specific optima for microbial growth and CUE. For example, a high share of small pore domains hampered fungal growth and reduced microbial CUE but facilitated microbial biomass turnover at the same time. Thus, we suggest that – superimposed upon agricultural management effects – habitat structural conditions and microbial carbon limitation mainly shape microbial physiology and CUE in arable soil systems.

Correction: Kumar et al. Sustainable Intensification of Cropping Systems under Conservation Agriculture Practices: Impact on Yield, Productivity and Profitability of Wheat. Sustainability 2023, 15, 7468

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Association between foreign agricultural investments and adoption of soil and water conservation practices in Uganda

ObjectivesRecently, some developing countries are promoting foreign agricultural investments in Agriculture to exploit currently under-exploited land. Yet, the benefits to recipient countries remains less understood and inconclusive. The study sought to understand the association between proximity to a foreign agricultural investments (FAI) and adoption of soil and water conservation farming methods by smallholder farmers in Uganda.MethodologyWe used cross-sectional data collected from a total of 1,181 smallholder respondents, sampled through a multi-stage random sampling process resulting in three independent samples from South-western, Central and Northern Uganda. Using logistic regression analysis and pooled data, we study the association between proximity to a FAI and other factors that influence the adoption of soil and water conservation farming practices by smallholder farmers in Uganda.ResultsDescriptive results show that at the aggregate level proximity to a FAI, the education level of the farmer and ownership of information and communication assets (radio and mobile phone) are significantly different between adopter and non-adopters of soil and water conservation farming methods in the research area. The econometric findings of the study suggest that proximity to a foreign agricultural investments (FAI) has weak but significant spillovers on soil and water conservation farming practices of smallholder farmers it their vicinity with possible site specific variations that warrant more in-depth investigation. The effect of proximity to FAI on the adoption of soil and water conservation farming practices is complemented by the education level of the farmer and access to means of communication (radio, and in particular mobile phone set) indicating the importance of information and also broader socio-economic conditions.RecommendationWe recommend policies that enhance increased exposure of smallholder farmers to FAI especially those that help promote rural digital penetration through increased band width, FM radios and affordable data packages.

The Contribution of Conservation Agriculture on Environmental Protection in Rwanda

Purpose: The study aimed to assess the contribution of Conservation agriculture on Environmental protection in Rwanda: case of Kayonza District. Materials and Methods: The study reviewed different studies related to Conservation agriculture and Environmental protection and used qualitative and quantitative approaches. The Data were collected using a questionnaire and face-to-face interview on Sample composed by 404 Respondents from Kayonza district. The data collected and analyzed by using Distributive statistics. Findings: The study indicated that CA techniques are contributing in environmental protection and there is a relationship between adopting Conservation Agriculture (CA) techniques and environmental protection. The decrease in organic matter content and high soil erosion are affecting soil fertility and health and one of the main causes of global warming is also intensive chemical fertilization of agricultural crops. In contrast, CA techniques combine minimum soil disturbance, mulching, water holding capacity, reduce soil compaction, reduce soil erosion and improve soil fertility and application of organic fertilizers and re use of crop residues, Study have shown that farmers who adopt CA experience the improvement and there improve. The study underscores the importance of adopting CA techniques to reduce the cost and protect environment. Implications to Theory, Practice and Policy: By adopting CA practices, farmers can contribute to the protection of natural resources, conservation of biodiversity, and mitigation of climate change while maintaining agricultural productivity by promoting sustainable land management practices that conserve soil, water, and biodiversity, mitigate climate change impacts, and reduce environmental degradation associated with conventional agricultural practices. But not all small holder farmers involved in implementing all CA techniques due to different factors, NGOs and Government can collaborate to develop subsidies, grants, and funding programs specifically aimed to promote conservation agriculture. By adopting CA techniques, agriculture in the next decade will have to sustainably produce more food from less land through more efficient use of natural resources and with minimal impact on the environment in order to meet growing population demands.

Monitoring the Spatial Distribution of Cover Crops and Tillage Practices Using Machine Learning and Environmental Drivers across Eastern South Dakota

The adoption of conservation agriculture methods, such as conservation tillage and cover cropping, is a viable alternative to conventional farming practices for improving soil health and reducing soil carbon losses. Despite their significance in mitigating climate change, there are very few studies that have assessed the overall spatial distribution of cover crops and tillage practices based on the farm’s pedoclimatic and topographic characteristics. Hence, the primary objective of this study was to use multiple satellite-derived indices and environmental drivers to infer the level of tillage intensity and identify the presence of cover crops in eastern South Dakota (SD). We used a machine learning classifier trained with in situ field samples and environmental drivers acquired from different remote sensing datasets for 2022 and 2023 to map the conservation agriculture practices. Our classification accuracies (>80%) indicate that the employed satellite spectral indices and environmental variables could successfully detect the presence of cover crops and the tillage intensity in the study region. Our analysis revealed that 4% of the corn (Zea mays) and soybean (Glycine max) fields in eastern SD had a cover crop during either the fall of 2022 or the spring of 2023. We also found that environmental factors, specifically seasonal precipitation, growing degree days, and surface texture, significantly impacted the use of conservation practices. The methods developed through this research may provide a viable means for tracking and documenting farmers’ agricultural management techniques. Our study contributes to developing a measurement, reporting, and verification (MRV) solution that could help used to monitor various climate-smart agricultural practices.

Chemical speciation, reactivity, and long-term burial of sedimentary phosphorus in Green Bay, a seasonally hypoxia-influenced freshwater estuary

Sediment cores were collected along a trophic gradient in Green Bay, a seasonally hypoxia-influenced freshwater estuary in Lake Michigan, to measure various phosphorus (P) species, including exchangeable-P (Ex-P), iron-bound-P (Fe-P), biogenic-apatite and/or CaCO3-associated-P (CFA-P), organic-P (Org-P) and detrital-apatite-P (Detr-P). Although total phosphorus (TP) decreased with increasing depth, different P species exhibited distinct vertical distribution patterns with different post-depositional behaviors. The Ex-P, Fe-P and CFA-P species were identified as potentially bioavailable-P (BAP). Little variation was observed for Org-P and Detr-P species, especially below the upper-active-layer, both serving as the primary sink for P in sediment. Detr-P% decreased consistently from the near river plume station to the open bay in the north. P accumulation rates were estimated at 25.1 mmol-P/m2/yr (779 mg-P/m2/yr) in the south, 10.9 mmol-P/m2/yr (338 mg-P/m2/yr) in the central region, and 8.1 mmol-P/m2/yr (252 mg-P/m2/yr) in the north of Green Bay, showing a decrease in the depth of the upper active layer for P regeneration along the south-north transect. The overall potential P regeneration back into the water column increased from 2.8 mmol-P/m2/yr (87 mg-P/m2/yr) in the south, and 3.3 mmol-P/m2/yr (101 mg-P/m2/yr) in the central region to 5.6 mmol-P/m2/yr (173 mg-P/m2/yr) in the north of the bay, corresponding to P burial efficiencies of ∼89 %, 70 % and 31 % along the trophic gradient. The recent decrease in Detr-P and thus the increase in BAP over the last 2–3 decades could be related to anthropogenic activities, such as damming and implementation of agricultural conservation practices. Conversely, a recent increase in TOC/TOP ratios may reflect the increased extent of trophic status and seasonal hypoxia in bottom waters and enhanced regeneration and recycling of particulate P in Green Bay since the 1960s. New results from this study provide an improved understanding of the linkage between sources, internal cycling, and long-term burial of P in the basin.

Coastal Salinity Management and Cropping System Intensification through Conservation Agriculture in the Ganges Delta

Soil salinity is the major constraint for cropping system intensification in the coastal region of the Ganges Delta. Salts build up on the soil surface, as well as in the crop root zone, due to the capillary rise in underground brackish water, hampering the growth and development of crops and resulting in mortality and low yields. We studied, for three years (2020–2021 to 2022–2023), the effect of conservation agricultural practices (zero tillage planting, crop residue recycling, and crop rotations) on the major soil properties (soil salinity and organic carbon status), crop performance (yield and economics), and water footprint. Conservation agricultural practices significantly reduce soil salinity, build soil organic carbon, reduce water footprint, and increase the profitability of cropping systems compared to tillage-intensive conventional practices. Under conventional agriculture, the sole cropping of rice is more profitable than double and triple cropping systems.

Effect of long-term tillage practices on soil nitrogen, phosphorus and sulfur release under different nitrogen management options

The conservation agriculture (CA), presents a promising alternative for restoring soil health and achieving sustainable crop production. In addition, one cannot follow the same nitrogen management of conventional framing in the CA as the crop residue retained leads to N mineralization/immobilization. Hence, the present research was aimed to determine the effect of CA and nitrogen managements on soil nitrogen, phosphorus and sulfur release and the enzymes involved in their mineralization. The results revealed that the CA practice significantly enhanced the mineral N, Olsen P and CaCl2–S release and the soil enzymes involved in this mineralization cycles compared to CT + R plots. Similarly, all the nitrogen fertilizer receiving subplots also recorded significantly higher mineral N, Olsen P and CaCl2–S release and the enzymes involved compared to the control. Furthermore, throughout the incubation period the Urea super granule + Greenseeker treatment significantly outperformed the RDN plot with respect to NO3–N and CaCl2–S release. Whereas, the Urea + Greenseeker treatment registered significantly higher NO3–N and CaCl2–S over RDN plot from 30 and 45 days after incubation, respectively. The NH4–N and Olsen P release had increasing trend up to 45 days after incubation and thereafter it decreased. In nutshell, the research emphasizes the significance of CA alongside optimum nitrogen management approaches in enhancing the soil enzymatic activities and nutrient mineralization. These outcomes hold significance for both farmers and researchers seeking ecologically sound and productive agricultural methods to enhance crop output and maintain soil quality.

Effect of adoption of conservation agriculture on household food security of smallholder maize farmers in Ghana

This cross-sectional study set out to examine the effect of conservation agriculture (CA) adoption on the food security of smallholder maize farmers in the Adansi Akrofuom District in the Ashanti Region of Ghana. Using the multistage sampling technique, 400 small-scale farmers who have been introduced to CA were selected. The findings of the study show that crop rotation, row planting, fertilizer application, improved seeds and cover cropping were the CA practices often implemented by the farmers. Age of the farmer, household size, years of education, religion, access to extension, frequency of group visits, and the area under CA cultivation were significant predictors of farmers' adoption of CA practices. Implementation of CA practices has a significant effect on household level of food security. There was an agreement among the farmers that access to credit is the greatest challenge they face in using CA practices. The paper proposes that efforts towards the continuous and high adoption of CA practices must be given more attention since they can affect farmers’ household food security.

Effect of Two Years of Conservation Agricultural Practices on Weed Seed Banks Evaluated Using Three Techniques

Effect of Two Years of Conservation Agricultural Practices on Weed Seed Banks Evaluated Using Three Techniques

Productivity, nutrient uptake and nitrogen economy of wheat (Triticum aestivum) in a conservation agriculture-based cotton (Gossypium herbaceum)–wheat system

Conservation agriculture (CA) practices like zero-till and residue retention along with nitrogen management is vital for improving degraded soil health and optimizing the yield potential of wheat (Triticum aestivum L.) crop. Present study was carried out during winter (rabi) seasons of 2021–22 and 2022–23 at ICAR-Indian Agricultural Research Institute, New Delhi for optimizing wheat productivity in a conservation agriculture-based cotton (Gossypium herbaceum L.)-wheat system. The experiment was laid out in a randomized complete block design (RCBD) with three replications consisting of combination of 3 different crop establishment methods, viz. permanent broad bed (PBB), permanent narrow bed (PNB) and zero-till flatbed (ZTFB) with residue (R) and without residue along with 2 doses of nitrogen (75N, 100N) and conventional tillage (CT). The CA-based practices showed overall superior response in terms of growth, yield and nutrients uptake of wheat than CT. Among them, the PBBR100N resulted in significantly higher plant height, leaf area index, dry-matter accumulation, crop growth rate, and relative growth rate compared to PNB, PBB, ZTFB and CT. This treatment led to significantly higher grain (16.2–19.4%) and straw (9.6–11.6%) yields than CT. The net returns and benefit cost ratio (23.4% and 27.9%) were also higher than that in CT. Again, in this treatment, N uptake by wheat crop was higher by 85%, P uptake by 53.1%, and K uptake by 40.1%, and available soil N, P and K by 16.1, 25.3 and 43.7%, respectively than CT. Therefore, the study suggests that the adoption of CA-based practices with broad bed in Indo-Gangetic Plains will not only enhance the productivity of wheat but also result in improved soil health by restoring soil fertility.

Assessing the Multifaceted Tradeoffs of Agricultural Conservation Practices on Ecosystem Services in the Midwest U.S.

A comprehensive understanding of the potential effects of conservation practices on soil health, crop productivity, and greenhouse gas (GHG) emissions remains elusive, despite extensive research. Thus, the DeNitrification–DeComposition (DNDC) model was employed to evaluate the impact of eleven commonly practiced management scenarios on ecosystem services in the Western Lake Erie Basin, USA, from 1998–2020. Out of eleven scenarios, eight were focused on corn–soybean rotations with varied nitrogen application timing (50% before planting and 50% at either fall or spring during or after planting), or nitrogen source (dairy slurry or synthetic fertilizer (SF)), or tillage practices (conventional, no-till), or cereal rye (CR) in rotation. Remaining scenarios involved rotations with silage corn (SC), winter crops (CR or winter wheat), and alfalfa. The silage corn with winter crop and four years of alfalfa rotation demonstrated enhanced ecosystem services compared to equivalent scenario with three years of alfalfa. Applying half the total nitrogen to corn through SF during or after spring-planted corn increased yield and soil organic carbon (SOC) sequestration while raising global warming potential (GWP) than fall-applied nitrogen. The no-till practice offered environmental benefits with lower GWP and higher SOC sequestration, while resulting in lower yield than conventional tillage. The incorporation of CR into corn–soybean rotations enhanced carbon sequestration, increased GHG emissions, improved corn yield, and lowered soybean yield. Substituting SF with manure for corn production improved corn yield under conventional tillage and increased SOC while increasing GWP under both tillage conditions. While the role of conservation practices varies by site, this study’s findings aid in prioritizing practices by evaluating tradeoffs among a range of ecosystem services.

Enhancing productivity, soil health, and reducing global warming potential through diverse conservation agriculture cropping systems in India's Western Indo-Gangetic Plains

ContextThe rice-wheat (RW) system, spanning 13.5 million hectares in South Asia, is crucial for food security and livelihoods. However, intensive conventional tillage-based practices have harmed soil and environmental health, decreased productivity trends and increased greenhouse gas emissions. ObjectiveThis study aims to develop resilient, climate-smart cropping systems within the RW system, focusing on soil and crop productivity, economic viability, and reduced greenhouse gas (GHG) emissions. MethodsOver eight years, the study evaluated diverse parameters compared to farmer practices (FP) in seven scenarios (Sc), including one representing FP (Sc1) and six based on conservation agriculture (CA) principles. The study assessed system crop productivity, economic returns, soil quality (organic carbon; OC, nitrogen; N, phosphorus; P, potassium; K contents, bulk density; BD, soil aggregation, infiltration rates, microbial counts, and earthworm density), and GHG emissions. ResultsCA-based scenarios (Sc2 to Sc7) showed improved soil quality, lower bulk density, enhanced soil aggregation, and increased infiltration rates compared to Sc1. In the 0–15 cm layer, surface soil organic carbon (OC) and C stock were 63.7 % and 49.6 % higher, respectively, in CA-based scenarios. Additionally, available N, P and K contents in the surface layer increased by 10.2 %, 28.6 %, and 21.8 % under CA-based scenarios. Adoption of CA in intensified maize-based scenarios (Sc4 and Sc5) led to the increased system and economic yields, higher soil quality index (SQI), reduced GHG emissions and increased C stock compared to Sc1. ImplicationsThe study highlights that Conservation Agriculture (CA) practices and diversified crop rotations can address issues like falling crop productivity, reduced economic returns, soil degradation, and increasing environmental impacts in northwestern India's traditional rice-wheat system. However, widespread adoption requires government policies, including C credit payments and guaranteed markets with supportive pricing.

Identifying Credit Accessibility Mechanisms for Conservation Agriculture Farmers in Cambodia

As the expected cost of conservation agriculture (CA) inputs becomes an issue for farmers, financial institutions (FIs) play an essential role in promoting CA, a set of agricultural management practices with multiple positive effects. This research aimed to determine influencing factors, to rank challenges, and identify mechanisms for farmers to access agricultural credit for adoption of CA management practices in Cambodia. It was administered by conducting a survey of 242 randomly selected households for face-to-face interviews and conducting key informant interviews from purposive samples of 28 participants in Battambang and Preah Vihear provinces. The results indicated that influencing factors, including the family, adult labor and total farm size, had a positive relationship with farmers’ accessibility to agricultural credit, whereas age was negative. However, education year, farm size for main crops, on-farm income and farm experience were not significantly associated. High interest rates were the significant first-order challenge ranked, followed by document process complication, limited agricultural credit information, limited collateral security and a few other challenges. Support and improved process mechanisms to enhance credit accessibility are required to engage with multiple stakeholders, including farmers, FIs, non-government organizations (NGOs) and government officers. There has been a reduction in agricultural credit interest rates and incentives for importing CA inputs by the government, while provision of information support for agribusiness plans by NGOs which have implemented development project activities were considered as the main support mechanism. An improved process mechanism at the farmers’ level needs to include access to credit with low interest rates and a straightforward documentation process, whereas the FI level requires a business plan for lending decisions. It is evident that high lending rates hinder access to agricultural credit and the improvement of support and improved process mechanisms are necessary to better promote CA practices among farmers in Cambodia.

Conservation agriculture practices in Indian mustard (Brassica juncea)-basedcropping systems for enhanced productivity and profitability

Conservation agriculture practices in Indian mustard (Brassica juncea)-basedcropping systems for enhanced productivity and profitability

Tillage and mulching influence weed community dynamics and crop productivity of Sesbania alley–based food–fodder systems in rainfed agro-ecosystems

Context or problemCrop yield in rain-fed agro-ecosystems is limited by low soil moisture availability and weeds. Objective or research questionThis study aimed to answer the questions- 1. Do tillage practices, mulching and Sesbania alley-based food-fodder cropping system affect weed dynamics under rainfed agro-ecosystem? and 2. Is the productivity of a Sesbania alley-based rainfed food-fodder system affected by tillage practice, mulching or crop sequence? MethodsA four-year field experiment was conducted with Sesbania alley-based food-fodder systems (sorghum – chickpea; sorghum – barley; sorghum – mustard), and three tillage practices (conventional tillage; minimum tillage during rainy season - zero tillage during winter season; conventional tillage during rainy season - zero tillage during winter season) with and without mulch. ResultsDuring the study period, conservation agricultural techniques resulted in a shift in weed flora in all Sesbania alley-based cropping systems. Grass, broadleaf, and total weed densities declined by 8–9%, 35–38%, and 11–13%, respectively, across diverse cropping systems from 2014 to 15; however, sedge population increased (13–29% increase) during the same period. Mulching practices considerably reduced sedge density compared to the without-mulch treatment in all the tillage combinations. The lowest total weed biomass was recorded for minimum tillage during the rainy season and zero tillage + mulching treatment (17 g m–2) during the winter season. Weed species abundance and dominance were greater in 2014, while the diversity and evenness of weed species were higher in 2016, which indicates a weed shift. Sesbania hedgerow + (sorghum-mustard) with conventional tillage during the rainy season and zero tillage during the winter season without mulching had the highest weed diversity index and evenness than that of other treatment combinations. The Sesbania dry matter (DM) yield was significantly higher by 13% and 11% in minimum tillage during the rainy season and zero tillage during the winter season with mulching compared to conventional tillage without mulch in 2015–16 and 2016–17, respectively. However, tillage and mulching had a significant effect on the grain and straw yields of winter crops. All the tillage practices with Sesbania mulching recorded higher grain and straw yields for winter crops compared to the un-mulched treatments. ConclusionsThe innovative Sesbania alley-based rainfed food-fodder system, along with reduced tillage and mulching, improved productivity and altered weed dynamics. Implications or significanceThe knowledge gathered on weed dynamics may aid in determining weed management tactics under conservation agricultural practices. Double cropping is possible without compromising fodder needs by employing suitable tillage and mulching procedures, as well as Sesbania alley-based cropping systems.

Impact of Fertilizer and Mulch on Growth, Yield and Quality of Carrot in Arecanut Cropping System Under Conservation Agriculture Practices

This study aims to comprehensively assess the influence of conservation agriculture techniques, encompassing reduced tillage, cover cropping (live mulch) and nutrient levels on a range of growth parameters and the ultimate yield of crop. As per the principles of conservation agriculture i.e., soil was disturbed minimally, berseem mulch was incorporated in the experiment and carrot was raised under arecanut plantation during rabi and it was succeeded by mint crop in pre-kharif season. Experiment was laid out in Randomized block design with seven treatments of different nutrient doses and mulch replicated thrice. Field experiments were conducted across two growing seasons i.e., 2019-20 and 2020-21 during Rabi (Winter) at Balindi research farm, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur. Precise measurements and meticulous analyses were conducted on key parameters; Vegetative growth i.e., plant height and number of leaves, yield attributing parameters like root length, diameter, weight and total yield of crop. TSS and beta carotene was also estimated. These parameters unequivocally indicate that conservation agriculture practices exert a substantial influence on both the growth and yield. Among various nutrient levels, higher dose of fertilizer (T4 - 120:90:120 NPK kg ha-1) with berseem (Trifolium alexandrinum L.) as a cover crop in the interspaces showed maximum vegetative growth i.e., plant height and number of leaves plant-1 at all growth stages (30, 60 and 90 DAS) while decreasing trend was observed in yield parameters with higher levels of nutrient doses, medium level of fertilizer dose (T5 - 90:60:90 kg ha-1 + berseem (Trifolium alexandrinum) recorded highest root length, diameter, weight and projected yield of 18.5cm, 3.58 cm, 118.37 g plant-1 and 26.63 t ha-1 respectively. These findings underscore the considerable potential of conservation agriculture practices as a sustainable approach to optimize carrot crop production. This research contributes valuable scientific insights that hold significant implications for agricultural stakeholders, including farmers and practitioners, seeking to fine-tune carrot cultivation methodologies while concurrently fostering soil health and environmental sustainability.

Conservation Agricultural Practices Influencing the Seasonal Weed Dynamic and Productivity of Wheat in the Trans Indo-Gangetic Plains of India

Conservation Agricultural Practices Influencing the Seasonal Weed Dynamic and Productivity of Wheat in the Trans Indo-Gangetic Plains of India

Impact of using cover crop on predation slug on corn in Pennsylvania

Farmers in Pennsylvania face a significant obstacle in the form of slug insect management. Aims of this study to determine impact of using cover crop against slug attacks in Pennsylvania. This study collaborated with a Pennsylvania regional no-till farming unit to assign three treatments to each farmer: no crop cover (CA), plastic mulch cover (CP), green rye cereal cover (CRH), and dry rye cereal cover (CRK). The experiment was carried out in May – August in 2023. The use of rye cereal cover crops, both in green and dry form, can also have the potential to reduce slug pests. These plants provide shelter and breeding ground for natural enemies of slugs. Plant residue mulching in conservation farming practices provide an effective and sustainable slug pest management strategy. The use of rye cereal can be a reference for farmers in anticipating slug pests in an environmentally friendly manner.

Impacts of conservation agriculture on soil C and N stocks and organic matter fractions: comparing commercial producer fields with a long-term small-plot experiment in Brown Chernozems of Saskatchewan

Conservation agriculture (CA) is increasingly promoted to build soil organic matter (SOM) based on findings from predominantly small-plot long-term agroecosystem experiments (LTAEs), with minimal on-farm data. Using commercial producer fields ( n = 20) in the Brown Chernozemic soil zones of Saskatchewan, Canada, which were sampled before (1996) and after (2018) adopting direct-seeding and continuous cropping (1997), we examined changes in soil organic carbon (SOC) and soil total nitrogen (STN) stocks, along with C and N stocks in particulate (POM) and mineral-associated organic matter (MAOM), and compared them to an LTAE in the same soil zone. After 21 years, SOC and STN stocks (0–30 cm depth) increased by 13% and 21%, respectively, in commercial producer fields, and were more pronounced in finer- than coarser-textured soils. Conversely, there were no significant changes (0–30 cm depth) after 18 years (1998–2016) with CA (continuous wheat and pulse-wheat under no-tillage (PW-NT)) in the LTAE, except that STN stock for PW-NT decreased by 7.7%. The estimated rate of change to 30 cm depth was similar between the commercial fields and LTAE for SOC (0.28 and 0.16 Mg C ha−1 year−1, respectively), but not STN (0.04 and −0.03 Mg N ha−1 year−1, respectively). Changes were more evident in the MAOM than POM fraction in both cases. Although the impact of CA may be similar, as observed for SOC, actual on-farm changes will depend on site-specific factors, and specific CA practice. Therefore, on-farm monitoring studies are needed for more accurate assessments of SOM changes and C sequestration potentials.