Nitrogen supply modulates nitrogen remobilization and nitrogen use of wheat under supplemental irrigation in the North China Plain
Xuejiao Zheng, Zhenwen Yu, Yongli Zhang, Yu Shi
Abstract
Abstract Excessive nitrogen (N) input and irrigation exacerbate N leaching in winter wheat production in the North China Plain (NCP). To explore the optimal N for better N remobilization and higher N utilization of wheat under water-saving irrigation will be conductive to less environmental contamination. A field experiment was conducted at 300 (N 300 ), 240 (N 240 ), 180 (N 180 ), and 0 (N 0 ) kg N ha −1 of N application under supplemental irrigation (SI) that brought the relative soil water content (RSWC) to 70% at jointing and 65% at anthesis. Compared with N 0 , N 180 improved the free amino acid content in the flag leaf and grain after anthesis, dry matter and plant N accumulation at maturity, N translocation amount of vegetable organs and its contribution to grain from anthesis to maturity. Compared to N 240 and N 300 , N 180 increased the N translocation efficiency of vegetable organs, and reduced the soil NO 3 -N residue in the 60–180 cm soil layer, which contributing to no significant reduction in grain yield and grain protein yield, but higher grain N recovery efficiency ( G RE N ), N recovery efficiency (RE N ), and N partial factor productivity (PFP N ). Positive relationships were found between leaf N translocation efficiency and grain yield, grain protein yield, PFP N , G RE N , and RE N . Therefore, N 180 is appropriate to obtain a steady grain yield over 7.5 t ha −1 for at least 2 years under SI based on RSWC in the NCP.