College of Surveying and Geo-informatics, North China University of Water Resources and Electric Power, Zhengzhou 450045, China.
Physical Geography and Environmental Change Group, Department of Environmental Sciences, University of Basel, Basel 4056, Switzerland.
Sci Total Environ. 2020 Sep 20;736:139478. doi: 10.1016/j.scitotenv.2020.139478. Epub 2020 May 16.
No tillage (NT) has been recommended as an essential conservation agriculture (CA) management in terms of water erosion control. However, the term of NT actually represents both NT and NT plus straw mulching (NTS) in a large amount of studies, which is out of the scope of its original meaning. Consequently, the mixed use of the two terms may cause biased estimate of the role of NT in erosion reduction. We aimed to distinguish actual roles of tillage reduction and residue retention in erosion control based on published data from field experiments of China. A database of paired experiments was compiled from 40 published literatures, with tillage practices including conventional tillage, reduced tillage, no tillage, and their combinations with residue retention. Variable-controlling approach was adopted to comprehensively identify the roles of tillage reduction and residue retention in runoff and soil loss reduction. Our results showed that residue retention caused significant decline of both water and sediment loss, whereas tillage reduction only led to insignificant change of runoff and soil loss. No tillage plus residue retention was also beneficial in terms of erosion control, very likely due to the application of residue retention. The results strengthen the higher influence of residue retention over tillage reduction with respect to soil and water conservation. It also challenges the conclusion of previous studies that NT could lead to the reduction of both runoff and soil loss based on the mixed use of NT and NTS. Furthermore, the efficiency of straw mulching in erosion control declines as application duration increases, indicating the effects of CA should not be overestimated in longer-term. The effectiveness of CA in erosion control also differs among various soil types. Overall, this study highlights the necessity of understanding the influences of tillage reduction, residue retention and the combination of the two managements in order to better evaluate and manage CA with respect to water erosion control, but the impacts of application duration of CA and soil types must be properly considered when adopting CA to reduce erosion.
免耕（NT）已被推荐为控制水蚀的重要保护性农业（CA）管理措施。然而，在大量研究中，NT 一词实际上既代表 NT 也代表大量 NT 加秸秆覆盖（NTS），超出了其原始含义的范围。因此，这两个术语的混合使用可能会导致对 NT 在减少侵蚀方面作用的估计产生偏差。我们旨在根据中国田间试验发表的数据来区分耕作减少和残茬保留在侵蚀控制中的实际作用。从 40 篇已发表的文献中汇编了一个田间试验数据库，其中耕作措施包括常规耕作、少耕、免耕以及它们与残茬保留的组合。采用变量控制方法全面识别耕作减少和残茬保留在减少径流量和土壤流失中的作用。结果表明，残茬保留显著降低了水和泥沙流失，而耕作减少仅导致径流量和土壤流失的变化不显著。免耕加残茬保留在控制侵蚀方面也是有益的，很可能是由于残茬保留的应用。结果加强了残茬保留对水土保持的影响高于耕作减少的观点。这也挑战了先前研究的结论，即 NT 可以减少径流量和土壤流失，这是基于 NT 和 NTS 的混合使用。此外，秸秆覆盖在侵蚀控制中的效率随着应用时间的增加而下降，表明在较长时间内不应高估 CA 的效果。CA 在侵蚀控制中的有效性在不同土壤类型之间也存在差异。总体而言，本研究强调了理解耕作减少、残茬保留以及两者结合管理的影响的必要性，以便更好地评估和管理 CA 以控制水蚀，但在采用 CA 减少侵蚀时，必须适当考虑 CA 的应用时间和土壤类型的影响。
