Basal application of controlled-release nitrogen fertilizer increases chinese cabbage production and decreases soil n20 emissions in northern china

This study aimed at exploring the potential of one-time basal application of controlled release nitrogen fertilizer (CRU) on reducing N2O emission and increasing economic benefits of Chinese cabbage production in Northern China. A micro-plot field experiment was conducted consecutive two years in Zhaoxian County, Hebei Province. Fertilization treatments included no fertilizer control (CK), routine urea N at 400 kg hre and 10% less rate treatment, both applied in basal: topdressing ratio of 4:6 (U, 90U), and CRU in 10% less N input and totally basal applied (90CRU). The closed static chamber-gas chromatography methods were used to monitor and analyze soil N2O emission during growing period. At harvest, the Chinese cabbage yield and N use efficiency (NUE) were determined. The results revealed that the N2O emission peaked in U and 90U treatments at 7-9 days after basal fertilization and 46 days after topdressing, while that in 90CRU was 14-17 days and 20-24 days after basal fertilization, respectively, and with significantly lower peak value than U and 90U treatment in 2020 and 2021 years. Compared with U, N2O emission flux and seasonal total N2O emissions significantly decreased by 62.83%, 52.03%, 30.13% and 52.99% in 90CRU during 2020 and 2021 year, respectively. Compared with U, the yield of Chinese cabbage and NUE was increased by 11.85% and 5.64% in 90CRU, during 2020 year, those was increased by 7.93% and significantly increased by 36.74% in 90CRU, during 2021 year. The significant linear positive correlation between the N 2 0 emission flux and soil NH. -N, NO3 -N content, the abundances of functional genes AOB amoA, nirS, nirK and narG. The N2O emission flux was significantly decreased by 90CRU due to lower soil NH4-N, NO3-N contents and nitrification, denitrification functional microbial genes. The CRU in 10% less N input and totally basal applied (90CRU) enhanced Chinese cabbage yields, N utilization rate and reduced yield-scaled N2O emissions in vegetable cropping systems.