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Agriculture has undergone dramatic technological and cultural changes over the past century. Many would argue that the changes have been unquestionably positive with huge gains in productivity, reduced labour requirements, and alleviation of food insecurity for most people. However, the adoption of increasingly specialized and separated crop and livestock enterprises has also had widespread negative consequences resulting in (a) decline in biodiversity, (b) degradation of groundwater and surface waters with agrochemical pollutants, (c) poor soil health with monoculture crop production and frequent soil disturbance, (d) intensive greenhouse gas emissions from both specialized cropping systems relying on external inputs and concentrated animal feeding operations that accumulate wastes, and (e) general lack of ecological integrity among components of these specialized systems. Diversified agricultural systems using annual and perennial forages offer opportunities to elevate ecological synergies when crop and livestock operations are integrated. Integrated crop‐livestock systems can internalize nutrient cycling, provide cultural control of weeds, insects and diseases, and share resources in a circular‐based agroecosystem. Cover crops could be transitioned into nutritious annual forages for livestock grazing on currently specialized crop production farms with appropriate local incentives. Perennial forages in ley farming or in pasture‐crop rotations have historical relevance and are a proven practice for conserving nutrients, improving soil health and enhancing biodiversity. Redesigning contemporary agriculture with mixed‐use farming techniques could greatly reduce soil erosion, improve water quality, and invigorate soil health. We suggest that incorporating different types of forages across a diverse landscape can enhance agricultural sustainability and ecological integrity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Negative impacts on the environment are a concern with specialized agriculture. [•] Soils rooted with perennial forages have high organic matter content. [•] High soil organic matter content contributes to high soil quality. [•] Improved soil quality with pasture–crop rotations can improve ecosystem services. [•] Review of science of pasture–crop rotations in temperate North and South America. [Copyright &y& Elsevier]

Prediction of soil organic C sequestration with adoption of various conservation agricultural management approaches is needed to meet the emerging market for environmental services provided by agricultural land stewardship. The soil conditioning index (SCI) is a relatively simple model used by the USDA-Natural Resources Conservation Service to predict qualitative changes in soil organic matter. Our objective was to develop a quantitative relationship between soil organic C derived from published field studies in the southeastern USA and SCI scores predicted from matching management conditions. We found that soil organic C sequestration (at 20 ± 5 cm depth) could be reliably related to SCI across a diversity of studies in the region using the regression slope: 1.65 Mg C ha SCI [which translated into a rate of 0.25 ± 0.04 Mg C ha yr SCI (mean±standard error of 31 slope estimates)]. The calibration of soil organic C on SCI scores will allow SCI to become a quantitative tool for natural resource professionals to predict soil organic C sequestration for farmers wanting to adopt conservation practices. [ABSTRACT FROM AUTHOR]

Aims: Cover crop species selection for soybean (Glycine max) production under no-tillage (NT) management may affect soil organic C sequestration by altering the quantity and quality of C inputs, thereby affecting cropping system sustainability. If so, the underlying mechanisms for such regulation are still unclear. Methods: We assessed changes in soil C and N fractions at 0-0.1 m depth and soil C stock at 0-0.6 m depth during the last three years of dry-season cover cropping in a soybean production system managed with NT for 9 years on a Rhodic Hapludox in Sao Paulo, Brazil. Dry-season management treatments were repeated yearly in a split-plot scheme. Main plots during the fall-winter were (1) ruzigrass (Urochloa ruziziensis), (2) grain sorghum (Sorghum bicolor), and (3) the intercropping of ruzigrass and sorghum. Subplots during spring prior to planting soybean were (a) pearl millet (Pennisetum glaucum), (b) sunn hemp (Crotalaria juncea), and (c) forage sorghum (Sorghum bicolor). Results: Soil C and N fractions were affected according to crop residue characteristics of the rotations. Higher soil C stocks in 2012 and 2015 (7 % an average) were observed at 0.2–0.4 m depth by ruzigrass compared to sorghum. High crop residue input with ruzigrass in the fall-winter sequestered 0.61 Mg C ha− 1 yr− 1 at 0-0.1 m soil depth compared with lower C sequestration using grain sorghum (0.29 Mg C ha− 1 yr− 1). Conclusions: The quantity and quality of crop residues impact its retention on soil surface controlling the dynamics of soil C and N fractions and can be considered relevant for soil C sequestration. These aspects could contribute to the mitigation of atmospheric CO2 in crop production systems. [ABSTRACT FROM AUTHOR]

Abstract: Semiarid Mediterranean climatic conditions and intensive tillage systems accelerate soil organic matter losses. Therefore, assessing agricultural practices that enhance storage of soil organic matter is needed. Stratification of soil properties with soil depth, expressed as a ratio, could indicate soil quality under different soil management. We measured soil depth stratification ratio (0–5/10–30cm and 0–5/30–50cm) of soil organic C (SOC), total N, active carbon (AC), water soluble carbon (WSC), and soil enzymatic activities [dehydrogenase activity (DHA) and β-glucosidase activity (BGA)] of a Typic Haploxerert in southern Spain. The experimental design consisted of a split–split plot design with three replications and soil properties evaluated at the end of 22 years. Tillage systems included conventional tillage (CT) and no tillage (NT). Dryland, 2-year crop rotations were wheat (Triticum aestivum L.)–fallow (WF), wheat–chickpea (Cicer arietinum L.) (WC), wheat–faba bean (Vicia faba L.) (WFb), wheat–sunflower (Helianthus annuus L.) (WS), and continuous wheat (WW). Nitrogen fertiliser rates were 0, 50 and 150kgNha−1. Stratification ratios of total N, WSC, AC, DHA, and BGA were most responsive to tillage systems; NT greater than CT. Stratification ratios of SOC, total N, WSC, AC and BGA were most responsive to crop rotation; WFb and WW greater than WF, WC, and WS. Stratification ratio of BGA was most responsive to N fertiliser rate; higher rates than no fertiliser. Stratification ratios of C and N fractions and enzymatic activities were responsive to choice of denominator used for ratio calculation. Tillage and crop rotation had more influence than N fertiliser rate in affecting stratification ratio of C and N fractions and enzymatic activities. Stratification ratio was relatively low (<2), perhaps due to the large shrinking and swelling characteristics of Vertisols. Stratification ratio of BGA was greater than of all other soil properties, suggesting that it might be a good indicator of soil quality under different soil management in Mediterranean conditions, particularly with Vertisols. This study indicated the value of stratification ratios to detect improvement in soil organic matter fractions and enzymatic activities (i.e. indicators of soil quality) with adoption of improved conservation management approaches. [Copyright &y& Elsevier]