关键词: 免耕, 产量效应, Meta-analysis, 玉米, 中国北方地区

Abstract: 【Objective】This study was conducted to reveal the influence mechanism and comprehensive effect of no-tillage on maize yield in Northern China. This study will provide valuable information for the application of no-tillage technology. 【Method】The maize in the northern region of China was taken as the research object. A total of 68 papers (including 82 available comparisons) were selected from published papers at home and abroad before May in 2017. Key information, containing experimental site, annual average precipitation, annual average temperature, cropping system, tillage pattern, experimental duration, experimental year, maize yield, standard deviation of maize yield, and replicate, were abstracted from each study. The site was divided into northwest region of China, northern region of China, and northeast region of China. The annual precipitation and average annual temperature was classified as ＜500 mm and ≥500 mm, ＜10℃ and ≥10℃, respectively. The experimental duration was split into four classes of 1-2 a, 3-5 a, 6-9 a, and ≥10 a. The tillage pattern was divided into flat planting and ridge planting. The cropping system was classified as continuous cropping and rotation cropping. Straw returning or not was also carried out. The analysis steps consist of heterogeneity test, comprehensive effect size calculation, publication bias test, sensitivity analysis, cumulative meta-analysis, and influence factor analysis. 【Result】There were no publication bias and extreme values among the obtained data. No-tillage could significantly increase maize yield compared with traditional tillage. The average yield increasing rate was 3.1% with a confidence interval of 0.7%-5.5%. The cumulative yield increasing rate under no-tillage was unstable before 2000 with average values of -0.7%-6.6%. The differences in cumulative yield increasing rates between no-tillage and traditional tillage, however, gradually changed from non-significant to significant after 2000. No-tillage showed a significant yield increasing rate (average value of 5.3% and confidence interval of 1.5%-9.2%) in northeastern region of China, while the yield effect was not significant in northern region of China and northwestern region of China (average value of -2.6%-6.4% and -1.0%-6.4%, respectively). Maize yield under no-tillage significantly increased in the regions where annual precipitation was less than 500 mm and average annual temperature was lower than 10℃, and in the conditions of rotation tillage and straw returning. The average yield increasing rate was 5.4% (confidence interval of 1.7%-9.1%), 3.8% (confidence interval of 0.8%-6.7%), 4.4% (confidence interval of 1.3%-7.5%), and 3.3% (confidence interval of 0.8%-5.8%), respectively. The yield effect of no-tillage between ridge planting and flat planting was not significantly different. After 2010, the yield effect of no-tillage was significant (average value of 6.1%), and the amplitude was small (confidence interval of 2.5%-9.7%). The average yield increasing rate increased first and then decreased with the extension of the no-tillage duration. The yield effect was significant and reached the maximum (average value of 3.8% and confidence interval of 1.6%-6.0%) when no-tillage lasted for 3-5 years. 【Conclusion】It helps to improve the effect of no-tillage in northeastern region of China and in regions where annual precipitation is less and annual average temperature is lower. The reasonable no-tillage durations are 3-5 years.  

Key words: no-tillage, yield effect, Meta-analysis, maize, northern region of China