Catálogo de publicaciones - revistas

<jats:title>Abstract </jats:title><jats:p>Conservation agriculture is often assumed to reduce soil N<jats:sub>2</jats:sub>O emissions. Yet, studies analyzing the specific effect of conservation agriculture practices on N<jats:sub>2</jats:sub>O emissions give contradictory results. Herein, we synthesized a comprehensive database on the three main conservation agriculture practices (cover crops, diversified crop rotations, and no-till and/or reduced tillage (NT/RT)) to elucidate the role of conservation practices on N<jats:sub>2</jats:sub>O emissions. Further, we used a random meta-forest approach to identify the most important predictors of the effects of these practices on soil N<jats:sub>2</jats:sub>O emissions. Averaged across all comparisons, NT/RT significantly decreased soil N<jats:sub>2</jats:sub>O emissions by 11% (95% CI: –19 to –1%) compared to conventional tillage. The reductions due to NT/RT were more commonly observed in humid climates and in soils with an initial carbon content &lt; 20 g kg<jats:sup>–1</jats:sup>. The implementation of cover crops and diversified crop rotations led to variable effects on soil N<jats:sub>2</jats:sub>O emissions. Cover crops were more likely to reduce soil N<jats:sub>2</jats:sub>O emissions at neutral soil pH, and in soils with intermediate carbon (~20 g kg<jats:sup>–1</jats:sup>) and nitrogen (~3 g kg<jats:sup>–1</jats:sup>) contents. Diversified crop rotations tended to increase soil N<jats:sub>2</jats:sub>O emissions in temperate regions and neutral to alkaline soils. Our results provide a comprehensive predictive framework to understand the conditions in which the adoption of various conservation agriculture practices can contribute to climate change mitigation. Combining these results with a similar mechanistic understanding of conservation agriculture impacts on ecosystem services and crop production will pave the way for a wider adoption globally of these management practices.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Soil health metrics with strong links to ecological function and agricultural productivity are needed to ensure that future management of agricultural systems meets sustainability goals. While ecological metrics and crop yields are often considered separately from one another, our work sought to assess the links between the two in an agricultural context where productivity is a key consideration. Here, we investigated the value of soil health tests in terms of their relevance to agricultural management practices and crop yields at contrasting long term cropping systems experiments. One site was on a sandy loam Leptic Podzol and the other on a sandy clay loam Endostagnic Luvisol. Furthermore, the experiments had different management systems. One contained legume-supported rotations with different grass-clover ley durations and organic amendment usage, while the other compared a range of nutrient input options through fertiliser and organic amendments on the same rotation without ley periods. Metrics included field tests (earthworm counts and visual evaluation of soil structure scores) with laboratory analysis of soil structure, chemistry and biology. This analysis included bulk density, macroporosity, pH, available phosphorus, exchangeable potassium, soil organic matter and potentially mineralizable nitrogen. Using a novel combination of long-term experiments, management systems and distinctive soil types, we demonstrated that as well as providing nutrients, agricultural management which resulted in better soil organic matter, pH, potassium and bulk density was correlated with higher crop yields. The importance of ley duration and potentially mineralizable nitrogen to yield in legume-supported systems showed the impact of agricultural management on soil biology. In systems with applications of synthetic fertiliser, earthworm counts and visual evaluation of soil structure scores were correlated with higher yields. We concluded that agricultural management altered yields not just through direct supply of nutrients to crops, but also through the changes in soil health measured by simple metrics.</jats:p>