[Effects of long-term no-tillage and stover mulching on maize yield and its stability]

Clarifying the differences of maize yield and its stability under long-term no-tillage with different stover mulching amounts can provide theoretical and technical supports for establishing and evaluating long-term conservation tillage pattern and promoting grain production. Based on a long-term conservation tillage field experiment in the mollisol area of Northeast China since 2007, we analyzed the interannual variation, variation coefficient and stability of maize yield during 2013 and 2019 across five treatments, i.e., no-tillage stover-free mulching (NT₀), no-tillage with 33% stover mulching (NT₃₃), no-tillage with 67% stover mulching (NT₆₇) and no-tillage with 100% stover mulching (NT₁₀₀), with the traditional ridge cropping (RT) as the control. The results showed that compared with RT, long-term no-tillage with stover mulching treatments could increase maize yield. NT₁₀₀ had the highest increasing rate of 11.4%, followed by NT₆₇ and NT₀, with the increasing rate of 11.0% and 10.4%, respectively. Maize yield exhibited a nonlinear relationship with the amount of stover mulch. The variation coefficient of maize yield under multi-year no-tillage with different stover mulching could be sorted as NT₆₇<RT<NT₁₀₀<NT₃₃<NT₀, and the yield sustainability index was NT₆₇>NT₀>NT₁₀₀>RT>NT₃₃, indicating that NT₆₇ treatment could significantly reduce the interannual fluctuation of maize yield and had better sustainability of yield. No-tillage stover mulching significantly increased soil total carbon and total nitrogen contents, which were significantly positively correlated with maize yield. In conclusion, compared with traditional tillage, no-tillage stover mulching could increase maize yield and soil carbon and nitrogen contents. Appropriate stover mulching (NT₆₇)had the potential to improve the stability and sustainability of maize yield.