Broadband crop rotation of cotton-grain-rape improved crop yield and light utilization efficiency

The cotton-grain-rape broadband crop rotation can fully utilize farmland resources, but the utilization characteristics of light energy resources of different crops in this planting system are still unclear. There were three treatments in this study, broadband crop rotation of cotton-grain-rape (BR), cotton monoculture (CM) and maize-wheat rotation (MR). Yield of cotton, maize and wheat, dry matter weight, leaf area index, extinction coefficient, light energy interception and other indicators were determined. Compared to CM and MR, BR increased the yield of cotton, maize, and wheat, the increment was 15.20%, 21.07%, and 16.13%, respectively. The dry weight of cotton and maize increased by 10.35% and 6.17%, respectively. From July 16th to September13th, the leaf area index of significantly increased by 7.89%、8.13%、9.42%、11.16% and 7.51% compared to BR. From July 24th to August 4th, the light interception rate of cotton significantly decreased by 3.59% and 3.24% compared to BR, respectively. The leaf area index, extinction coefficient, and PAR interception efficiency of maize and wheat did not show significant difference. Compared to CM and MR, the light interception of the whole growth period of cotton reduced by 3.14%, while the light interception of the whole growth period of maize increased by 0.76% significantly. There was no significant difference in the light interception of the whole growth period of wheat. Light use efficiency of cotton, maize, and wheat significantly increased by 18.81%, 6.76%, and 14.1%, respectively. Under this experiment, the edge row advantage and rotation effect simultaneously increase the yield of cotton, corn, and wheat, as well as the aboveground dry matter weight of cotton and corn, improve the accumulation and distribution of crop dry matter, and thereby enhance the light energy utilization efficiency of cotton, corn, and wheat. This study clarified the effects of cotton-grain-rape broadband crop rotation on the yield and canopy light energy utilization of cotton, maize, and wheat, providing a theoretical basis for the promotion and application of this model.