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

Liu, Chuang; Chen, Fang; Li, Zhiguo; Cocq, Kate Le; Liu, Yi; Wu, Lianhai

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 nutrient use efficiency. RESULT The comprehensive evaluation index had good fitness to that of single attribute, indicating that the comprehensive evaluation index was superior and reliable. Applying controlled release urea (rice in wheat and oilseed rape field: 150 kg N ha-1 , the other crops: 120 kg N ha-1 ) plus common urea (30 kg N ha-1 ) incorporated with straw from the previous season across the growing season for cereal and oilseed crop showed a slight improvement in seed productivity and N use efficiency among three cropping systems in the traditional evaluation method. Compared with the local farm practice (applying common urea of 150 kg N ha-1 ), applying the 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 paddy-upland cropping system, respectively. CONCLUSION Properly managing N application by applying partial and full controlled release urea with or without straw incorporation for a specific crop system has the potential to be a better compromise among yield, grain quality and soil fertility in southern China. This article is protected by copyright. All rights reserved.