Effect of Straw Incorporation on Corn Yield in North China: A Meta-Analysis

Crop straw incorporation (SI) is as an effective method of soil improvement, which is playing an increasingly important role in improving corn productivity, soil fertility and reducing nitrogen leaching and ammonia volatilization in North China. We conducted a meta-analysis to examine the effect of crop SI on corn yield in North China, and to investigate how the effect varies with region, climate, soil, duration of crop SI, cropping system, and application of inorganic fertilizer (nitrogen, phosphorus, potassium). Results indicated that crop SI significantly increased corn yield by 12.3% in North China. Crop SI had the most significant effect on improving corn yield under the annual precipitation ≤ 400 mm (18.6%) and mean temperature > 12 °C (15.4%) environment. The change rate of corn yield was higher with the experimental duration of 2–3 years (13.3%) than that of ≥4 years (8.52%). Corn yield responses to crop SI in the corn–corn cropping system (10.42%) were not as obvious as that in the corn–wheat cropping system (14.73%). Therefore, we conclude that crop SI could significantly increase corn yield, which can reduce environmental pollution and add farmer income.