Impacts of nitrogen practices on yield, grain quality, and nitrogen-use efficiency of crops and soil fertility in three paddy-upland cropping systems

Abstract

BACKGROUND: Global food security faces a number of challenges due to increasing population, climate change, and urbanization, while excessive use of nitrogen fertilizers has become a major challenge for sustainable, intensive agriculture. Assessing the impact of agronomic management practices on seed yield, grain quality, and soil fertility is a critical step in understanding nutrientuse efficiency. RESULT: The comprehensive evaluation index had good fitness to that of single attribute (i.e. seed yield, crop quality and soil fertility), indicating that the comprehensive evaluation index was reliable. Applying controlled-release urea (rice in wheat and oilseed rape field: 150 kg N ha−1, other crops: 120 kg N ha−1) plus common urea (30 kg N ha−1) incorporating straw from the previous season across the growing season for cereal and oilseed crops showed a slight improvement in seed productivity and Nuse efficiency among three cropping systems in the traditional evaluation method. Compared with local farm practice (applying common urea of 150 kg N ha−1), applying these practices in combination based on the outcome of the comprehensive evaluation index method decreased the seed yield by −1.27 ~ 29.8% but improved quality and soil fertility for the paddy-upland cropping system, respectively. CONCLUSION: Properly managing N application by applying partial and fully controlled release of urea with or without straw incorporation for a specific crop system has the potential to provide a better compromise among yield, grain quality, and soil fertility in southern China. © 2020 Society of Chemical Industry.