Livestock integration into soybean systems improves long‐term system stability and profts without compromising crop yields

Climate models project greater weather variability over the coming decades. High yielding systems that can maintain stable crop yields under variable environmental scenarios are critical to enhance food security. However, the efect of adding a trophic level (i.e. herbivores) on the long-term stability of agricultural systems is not well understood. We used a 16-year dataset from an integrated soybean- beef cattle experiment to measure the impacts of grazing on the stability of key crop, pasture, animal and whole-system outcomes. Treatments consisted of four grazing intensities (10, 20, 30 and 40 cm sward height) on mixed black oat (Avena strigosa) and Italian ryegrass (Lolium multiforum) pastures and an ungrazed control. Stability of both human-digestible protein production and proftability increased at moderate to light grazing intensities, while over-intensifcation or absence of grazing decreased system stability. Grazing did not afect subsequent soybean yields but reduced the chance of crop failure and fnancial loss in unfavorable years. At both lighter and heavier grazing intensities, tradeofs occurred between the stability of herbage production and animal live weight gains. We show that ecological intensifcation of specialized soybean systems using livestock integration can increase system stability and proftability, but the probability of win–win outcomes depends on management

Increasing crop rotational diversity can enhance cereal yields

Diversifying agriculture by rotating a greater number of crop species in sequence is a promising practice to reduce negative impacts of crop production on the environment and maintain yields. However, it is unclear to what extent cereal yields change with crop rotation diversity and external nitrogen fertilization level over time, and which functional groups of crops provide the most yield benefit. Here, using grain yield data of small grain cereals and maize from 32 long-term (10–63 years) experiments across Europe and North America, we show that crop rotational diversity, measured as crop species diversity and functional richness, enhanced grain yields. This yield benefit increased over time. Only the yields of winter-sown small grain cereals showed a decline at the highest level of species diversity. Diversification was beneficial to all cereals with a low external nitrogen input, particularly maize, enabling a lower dependence on nitrogen fertilisers and ultimately reducing greenhouse gas emissions and nitrogen pollution. The results suggest that increasing crop functional richness rather than species diversity can be a strategy for supporting grain yields across many environments

Crop rotational diversity can mitigate climate-induced grain yield losses

Diversified crop rotations have been suggested to reduce grain yield losses from the adverse climatic conditions increasingly common under climate change. Nevertheless, the potential for climate change adaptation of different crop rotational diversity (CRD) remains undetermined. We quantified how climatic conditions affect small grain and maize yields under different CRDs in 32 long-term (10-63 years) field experiments across Europe and North America. Species-diverse and functionally rich rotations more than compensated yield losses from anomalous warm conditions, long and warm dry spells, as well as from anomalous wet (for small grains) or dry (for maize) conditions. Adding a single functional group or crop species to monocultures counteracted yield losses from substantial changes in climatic conditions. The benefits of a further increase in CRD are comparable with those of improved climatic conditions. For instance, the maize yield benefits of adding three crop species to monocultures under detrimental climatic conditions exceeded the average yield of monocultures by up to 553 kg/ha under non-detrimental climatic conditions. Increased crop functional richness improved yields under high temperature, irrespective of precipitation. Conversely, yield benefits peaked at between two and four crop species in the rotation, depending on climatic conditions and crop, and declined at higher species diversity. Thus, crop species diversity could be adjusted to maximize yield benefits. Diversifying rotations with functionally distinct crops is an adaptation of cropping systems to global warming and changes in precipitation.</p

Commercial integrated crop-livestock systems achieve comparable crop yields to specialized production systems: A meta-analysis.

Production systems that feature temporal and spatial integration of crop and livestock enterprises, also known as integrated crop-livestock systems (ICLS), have the potential to intensify production on cultivated lands and foster resilience to the effects of climate change without proportional increases in environmental impacts. Yet, crop production outcomes following livestock grazing across environments and management scenarios remain uncertain and a potential barrier to adoption, as producers worry about the effects of livestock activity on the agronomic quality of their land. To determine likely production outcomes across ICLS and to identify the most important moderating variables governing those outcomes, we performed a meta-analysis of 66 studies comparing crop yields in ICLS to yields in unintegrated controls across 3 continents, 12 crops, and 4 livestock species. We found that annual cash crops in ICLS averaged similar yields (-7% to +2%) to crops in comparable unintegrated systems. The exception was dual-purpose crops (crops managed simultaneously for grazing and grain production), which yielded 20% less on average than single-purpose crops in the studies examined. When dual-purpose cropping systems were excluded from the analysis, crops in ICLS yielded more than in unintegrated systems in loamy soils and achieved equal yields in most other settings, suggesting that areas of intermediate soil texture may represent a "sweet-spot" for ICLS implementation. This meta-analysis represents the first quantitative synthesis of the crop production outcomes of ICLS and demonstrates the need for further investigation into the conditions and management scenarios under which ICLS can be successfully implemented

Moving niche agroecological initiatives to the mainstream: A case-study of sheep-vineyard integration in California

International audienceAcross the world, an increasing number of farmers are piloting agroecological systems. The recoupling of crops and livestock is one type of agroecological practice that has potential to help reduce the use of off-farm inputs, improve soil quality, and reduce costs for farmers. Yet, a major part of the world's agricultural landscapes remain dominated by conventional specialized crop and livestock practices. In particular, grazing animals in perennial cropping systems may reduce pesticide and fuel use, decrease labor, and build soil organic carbon and soil fertility. In this study, we examined adopters and non-adopters' perceptions of a niche system, integrated sheep vineyard systems (ISVS) in California. We aimed at understanding the conditions under which ISVS, a specific case of ICLS (integrated crop-livestock systems), could be mainstreamed. We then contextualized these interviews using the Multi-Level Perspective framework to analyze the levers favoring or impeding mainstreaming of this niche system. We considered both pull factors arising from changes in the landscape, and push factors arising through decentralized, grassroot processes. Our inductive analysis is a promising first insight into farmers' perceptions and motivations toward ISVS adoption in California, considering both vineyard managers and contractors (i.e. shepherds renting their sheep to vineyard managers). We found a positive perception of ISVS among both current adopters and non-adopters regarding the potential agronomic, environmental and economic benefits of these practices. All adopters were satisfied with this system as they experienced labor and fuel savings, soil quality improvement and marketing advantages. Local push factors (bottom-up levers emerging from the niche systems) were highlighted by interviewees as contributing to adoption. Push factors identified include knowledge exchange and networking between vineyard managers and developing marketing pathways for "carbon-positive" wool, meat and wine products. However, some pull factors (macro-economic and policy levers acting as top-down levers) could help move the system beyond limited adoption. We point out biotechnical and socio-economic research avenues to encourage the scaling-up of ISVS and ICLS more broadly. On the biotechnical dimension, we recommend continuing and scaling-out system experiments to redesign vineyards considering sheep integration and evaluate the effect of grazing on soil quality and fire management. On the socio-economic dimension, we encourage the exploration of relevant spatial scenarios through co-design of collaborative arrangements between vineyard managers and contractors at the landscape level. Greater research on the social, environmental and economic services provided by ISVS is urgently needed to inform state and federal agricultural policies, including whether such systems should be supported through payment for ecosystem services and as part of environmental good practices and fire safety recommendations

Improving Resilience of Northern Field Crop Systems Using Inter-Seeded Red Clover: A Review

In light of the environmental challenges ahead, resilience of the most abundant field crop production systems must be improved to guarantee yield stability with more efficient use of nitrogen inputs, soil and water resources. Along with genetic and agronomic innovations, diversification of northern agro-ecosystems using inter-seeded legumes provides further opportunities to improve land management practices that sustain crop yields and their resilience to biotic and abiotic stresses. Benefits of legume cover crops have been known for decades and red clover (Trifolium pratense) is one of the most common and beneficial when frost-seeded under winter wheat in advance of maize in a rotation. However, its use has been declining mostly due to the use of synthetic fertilizers and herbicides, concerns over competition with the main crop and the inability to fully capture red clover benefits due to difficulties in the persistence of uniform stands. In this manuscript, we first review the environmental, agronomic, rotational and economical benefits associated with inter-seeded red clover. Red clover adaptation to a wide array of common wheat-based rotations, its potential to mitigate the effects of land degradation in a changing climate and its integration into sustainable food production systems are discussed. We then identify areas of research with significant potential to impact cropping system profitability and sustainability

Orchard recycling improves climate change adaptation and mitigation potential of almond production systems.

There is an urgent need to develop climate smart agroecosystems capable of mitigating climate change and adapting to its effects. In California, high commodity prices and increased frequency of drought have encouraged orchard turnover, providing an opportunity to recycle tree biomass in situ prior to replanting an orchard. Whole orchard recycling (WOR) has potential as a carbon (C) negative cultural practice to build soil C storage, soil health, and orchard productivity. We tested the potential of this practice for long term C sequestration and hypothesized that associated co-benefits to soil health will enhance sustainability and resiliency of almond orchards to water-deficit conditions. We measured soil health metrics and productivity of an almond orchard following grinding and incorporation of woody biomass vs. burning of old orchard biomass 9 years after implementation. We also conducted a deficit irrigation trial with control and deficit irrigation (-20%) treatments to quantify shifts in tree water status and resilience. Biomass recycling led to higher yields and substantial improvement in soil functioning, including nutrient content, aggregation, porosity, and water retention. This practice also sequestered significantly higher levels of C in the topsoil (+5 t ha-1) compared to burning. We measured a 20% increase in irrigation water use efficiency and improved soil and tree water status under stress, suggesting that in situ biomass recycling can be considered as a climate smart practice in California irrigated almond systems

The nitrogen gap in soil health concepts and fertility measurements

Soil nitrogen (N) often limits productivity in agroecosystems, prompting fertilizer applications that increase crop yields but can degrade the environment. Nitrogen's dual role in both productivity and environmental quality should center it in soil health frameworks. We use recent evidence to argue that N availability is an emergent property of the integrated soil biogeochemical system and is strongly influenced by plant traits and their interactions with microbes and minerals. Building upon this, we theorize that the sources of plant and microbial N shift across soil health gradients, from inorganic N dependence in ecologically simple systems with poor soil health to a highly networked supply of organic N in healthy soils; ergo, investments in soil health should increase ecological complexity and the pathways by which plants can access N, leading to more resilient nutrient supplies and yields in a variable climate. However, current N assessment methods derive from a historical emphasis on inorganic N pool sizes and are unable to capture the shifting drivers of N availability across soil health gradients. We highlight the need to better understand the plant-microbial-mineral interactions that regulate bioavailable N as a first step to improving our ability to measure it. We conclude it will be necessary to harness agroecosystem complexity, account for plant and microbial drivers, and carefully integrate external N inputs into soils' internal N network to expand the routes by which N from organic pools can be made bioavailable. By emphasizing N in soil health concepts, we argue that researchers can accelerate advances in N use efficiency and resiliency.This article is published as Grandy, A. Stuart, Amanda B. Daly, Timothy M. Bowles, Amélie CM Gaudin, Andrea Jilling, Andrea Leptin, Marshall D. McDaniel, Jordon Wade, and Hannah Waterhouse. "The nitrogen gap in soil health concepts and fertility measurements." Soil Biology and Biochemistry 175 (2022): 108856. doi:10.1016/j.soilbio.2022.108856. Posted with permission.Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted

Increasing Crop Diversity Mitigates Weather Variations and Improves Yield Stability

<div><p>Cropping sequence diversification provides a systems approach to reduce yield variations and improve resilience to multiple environmental stresses. Yield advantages of more diverse crop rotations and their synergistic effects with reduced tillage are well documented, but few studies have quantified the impact of these management practices on yields and their stability when soil moisture is limiting or in excess. Using yield and weather data obtained from a 31-year long term rotation and tillage trial in Ontario, we tested whether crop rotation diversity is associated with greater yield stability when abnormal weather conditions occur. We used parametric and non-parametric approaches to quantify the impact of rotation diversity (monocrop, 2-crops, 3-crops without or with one or two legume cover crops) and tillage (conventional or reduced tillage) on yield probabilities and the benefits of crop diversity under different soil moisture and temperature scenarios. Although the magnitude of rotation benefits varied with crops, weather patterns and tillage, yield stability significantly increased when corn and soybean were integrated into more diverse rotations. Introducing small grains into short corn-soybean rotation was enough to provide substantial benefits on long-term soybean yields and their stability while the effects on corn were mostly associated with the temporal niche provided by small grains for underseeded red clover or alfalfa. Crop diversification strategies increased the probability of harnessing favorable growing conditions while decreasing the risk of crop failure. In hot and dry years, diversification of corn-soybean rotations and reduced tillage increased yield by 7% and 22% for corn and soybean respectively. Given the additional advantages associated with cropping system diversification, such a strategy provides a more comprehensive approach to lowering yield variability and improving the resilience of cropping systems to multiple environmental stresses. This could help to sustain future yield levels in challenging production environments.</p></div