Persistent soil carbon enhanced in Mollisols by well-managed grasslands but not annual grain or dairy forage cropping systems.

Intensive crop production on grassland-derived Mollisols has liberated massive amounts of carbon (C) to the atmosphere. Whether minimizing soil disturbance, diversifying crop rotations, or re-establishing perennial grasslands and integrating livestock can slow or reverse this trend remains highly uncertain. We investigated how these management practices affected soil organic carbon (SOC) accrual and distribution between particulate (POM) and mineral-associated (MAOM) organic matter in a 29-y-old field experiment in the North Central United States and assessed how soil microbial traits were related to these changes. Compared to conventional continuous maize monocropping with annual tillage, systems with reduced tillage, diversified crop rotations with cover crops and legumes, or manure addition did not increase total SOC storage or MAOM-C, whereas perennial pastures managed with rotational grazing accumulated more SOC and MAOM-C (18 to 29% higher) than all annual cropping systems after 29 y of management. These results align with a meta-analysis of data from published studies comparing the efficacy of soil health management practices in annual cropping systems on Mollisols worldwide. Incorporating legumes and manure into annual cropping systems enhanced POM-C, microbial biomass, and microbial C-use efficiency but did not significantly increase microbial necromass accumulation, MAOM-C, or total SOC storage. Diverse, rotationally grazed pasture management has the potential to increase persistent soil C on Mollisols, highlighting the key role of well-managed grasslands in climate-smart agriculture.

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.

Oat tillering and tiller traits under different nitrogen levels in an eucalyptus agroforestry system in Subtropical Brazil / Perfilhamento e características dos perfilhos da aveia submetida a níveis de nitrogênio em sistema agroflorestal com eucalipto no subtrópico brasileiro

In oat production, tillering persistence is the determinant of one important yield component, namely the number of panicles. This process is highly influenced by the inter- and intraspecific interactions of the agroecosystem, which in turn depend on agronomic practices. The hypothesis of this research is that nitrogen does not increase oat tolerance to negative interference from trees, so oat tillering persistence in grain production remains un-modified by nitrogen at distances relative to the eucalyptus tracks, within the alley cropping agroforestry system (ACS). Thus, nitrogen should not be used to increase oat yield potential in these systems. The objective of this study was to determine how the tillering persistence for grain production and oat (Avena sativa L. cv. 'IPR 126') tiller traits were influenced by nitrogen levels (12 and 80kg N ha-1) at five equidistant positions between two adjacent eucalyptus (Eucalyptus dunnii Maiden) double line tracks [20m (4mx3m)] in ACS and traditional no-till agriculture in subtropical Brazil. The experiment was conducted in a split-block randomized block design with four replicates. The goal was to evaluate the oat phytomass, tiller-to-main shoot phytomass ratio, tillers per main shoot, grain yield and tiller-to-main shoot grain yield ratio. The oat tillering persistence for grain production is dependent on different nitrogen levels at distances relative to adjacent eucalyptus tracks and therefore, different nitrogen levels should be used in those areas, to improve oat yield potential inside ACS in subtropical Brazil.

Na produção de aveia, a persistência do perfilhamento é determinante para um importante componente de rendimento, o número de panículas. Esse processo é bastante influenciado pelas interações interespecíficas e intraespecíficas no agroecossistema, que, por sua vez, depende das práticas agronômicas. A hipótese deste trabalho é que o nitrogênio não aumenta a tolerância da aveia à interferência negativa das árvores, logo, a persistência do perfilhamento para produção de grãos não é modificada pelo nitrogênio em distâncias relativas às faixas de eucaliptos, em sistema agroflorestal em aleias (SAF). Assim, o nitrogênio não deve ser utilizado para aumentar o potencial de rendimento da aveia nestes sistemas. O objetivo deste trabalho foi determinar como a persistência do perfilhamento para produção de grãos e as características dos perfilhos da aveia (Avena sativa L. cv. 'IPR 126') são influenciados por níveis de nitrogênio (12 e 80kg N ha-1), em cinco posições equidistantes entre duas faixas adjacentes de linhas duplas [20m (4mx3m)] de eucalipto (Eucalyptus dunnii Maiden) e agricultura tradicional de plantio direto, no subtrópico brasileiro. O experimento foi realizado em faixas, no delineamento de blocos ao acaso, com quatro repetições. Foram avaliados a fitomassa da aveia, a razão de fitomassa entre o colmo principal e os perfilhos, o número de perfilhos por colmo principal, o rendimento de grãos e a relação do rendimento de grãos entre o colmo principal e os perfilhos. A persistência do perfilhamento para produção de grãos de aveia é dependente de diferentes níveis de nitrogênio em distâncias relativas a faixas adjacentes de eucaliptos, portanto, diferentes níveis de nitrogênio devem ser utilizados nessas distâncias, para aumentar o potencial de rendimento da aveia nos SAF no subtrópico brasileiro.