Long-term and excessive fertilization could enhance crop yields but lead to soil acidification and consequent environmental pollution. Leguminous crops or green manure (such as alfalfa), as nitrogen fixing plants, can fix nitrogen from the atmosphere by the rhizobia, which could increase soil fertility and crop yields. Comparison with conventional agriculture, legume-based cropping rotations can reduce the use of N fertilizer. Traditional rotation systems (wheat-maize and wheat-cotton) in North China Plain always require a large amount of chemical fertilizer. Therefore, sustainable cropping rotation is needed to alleviate environmental problems. In this study, two legume crops (soybean and alfalfa) are used to replace maize and wheat in summer and winter, respectively, to reduce the use and negative impacts of fertilizer on the environment.
A randomized complete block experiment has been conducted in the present study. The experiment including four treatments: 1) wheat-cotton (WC), 2) wheat-maize (WM), 3) wheat-soybean (WS), and 4) alfalfa-maize (AM), and each treatment replicated four times. Sixteen 15.5 m × 8 m plots were arranged in a 4 × 4 matrix with 0.5 m buffer zone between any two adjacent plots.
The plot layout of the experiment
Innovation Scientists and Technicians Troop Construction Projects of Henan Province (114200510016)
Wenjuan Wang, Xianghui Liu, Yaojun Zhang