Wood Stephen A, Bowman Maria
The Nature Conservancy, Arlington, VA, USA.
Yale School of the Environment, New Haven, CT, USA.
Nat Food. 2021 Feb;2(2):97-103. doi: 10.1038/s43016-021-00222-y. Epub 2021 Feb 18.
Cover crops are touted for their potential agronomic and environmental benefits, and are currently incentivized through state, federal and private investment in the USA. There is a need to quantify the impact of on-farm use of cover crops at spatial (2-5 years) and temporal (regional-to-national) scales aligned with such investment programmes. Here we report soil health data from a farmer-led trial of cover crops on 1,522 strip-years, from 78 farms across 9 US states over 5 years. We found that up to 5 years of cover crop use had small but increasing impacts on four of six selected soil health indicators, with active carbon concentration responding the most rapidly. Soil texture, the length of time a field was in the trial and a farm-level random effect were also strongly related to soil health properties. Our results fit with evidence from controlled trials and suggest that the use of cover crops can begin to influence soil health within several years after adoption.
覆盖作物因其潜在的农艺和环境效益而备受推崇，目前在美国，州、联邦和私人投资都在鼓励种植覆盖作物。有必要在与此类投资计划相匹配的空间（2 - 5年）和时间（区域到国家）尺度上，量化农场使用覆盖作物的影响。在此，我们报告了一项由农民主导的覆盖作物试验的土壤健康数据，该试验涵盖了美国9个州78个农场的1522个条带年，历时5年。我们发现，长达5年的覆盖作物使用对六个选定土壤健康指标中的四个产生了虽小但不断增加的影响，其中活性碳浓度的响应最为迅速。土壤质地、田地参与试验的时长以及农场层面的随机效应也与土壤健康特性密切相关。我们的结果与对照试验的证据相符，表明使用覆盖作物在采用后的几年内就能开始影响土壤健康。
