氮肥运筹对稻茬小麦干物质、氮素转运及氮素平衡的影响

为给稻茬小麦高产、优质栽培中合理施氮提供依据,以低蛋白小麦品种宁麦9号和高蛋白小麦品种豫麦34号为材料,设置不同施氮水平(0、150、225和300 kg·hm-2)及基追比(基肥∶追肥为1∶9、3∶7、5∶5和7∶3),研究氮肥运筹对小麦植株C-N积累与转运规律、产量、蛋白质含量及氮素利用的影响。结果表明,适当增加施氮量及追肥比例可同步提高两小麦品种籽粒产量和蛋白质含量。随施氮量和追肥比例的增加,两品种干物质转运量均呈先增后降的趋势,而干物质转运效率及其对籽粒产量的贡献率则显著降低。营养器官氮素转运量随施氮量增加而增加,随追肥比例增加先增后降;氮素转运率及其对籽粒氮素贡献率则随施氮量和追肥比例增加而下降。相关分析表明,提高花后干物质积累是提高小麦产量的重要途径,而促进花前营养器官贮存氮素向籽粒的转运是提高小麦蛋白质含量的重要措施。增加施氮量和基肥比例显著增加了两品种氮素的表观损失量并降低了氮素利用效率。本试验条件下,增施氮肥至225 kg·hm-2,追肥比例宁麦9号≤50%、豫麦34号为50%～70%可同步提高两品种籽粒产量、品质和氮素利用效率,降低氮素损失。

Effect of Nitrogen Application on Translocation of Dry Matter and Nitrogen, and Nitrogen Balance in Winter Wheat under Rice-wheat Rotation

Field experiments were conducted to investigate the effects of nitrogen(N) rates (N0, N150, N225 and N300) and topdressing ratios (N1/9, N3/7, N5/5 and N7/3) on post-anthesis dry matter and N assimilation and translocation, using wheat cultivars with different grain protein contents, i.e. Ningmai 9 (low protein) and Yumai 34 (high protein). The results showed that grain yield and protein content increased with increasing of an appropriate N rate and topdressing ratio. With the increment of N rate and topdresssing ratio appropriatly, dry matter translocation amount increased. However, dry matter transfer efficiency and the contribution of dry matter translocation to grain yield decreased when more N fertilizer and topdressing ratio was applied. N tranlocation amount increased with an increase of N rate and an appropriate topdressing ratio, but N translocation efficiency and the contribution of N translocation to grain N decreased with the increment of N rate and topdressing ratio. The correlation analysis indicated that increasing post-anthesis dry matter accumulation was favorable for improving grain yield and increasing N translocation from vegetative organs to grain was favorable for improving grain protein content. High N rate and basal ratio increased N loss amount and decreased N utilization. It is suggested that the N rate was 225 kg·hm^-2, topdressing ratio was not more than 50% for Ningmai 9, and 50%~70% for Yumai 34 had a better grain yield, protein content and N utilization efficiency, reduced N loss.