氮肥运筹模式对冬小麦氮素吸收利用的影响

Effects of Nitrogen Application Model on Nitrogen Absorption and Utilization in Winter Wheat

为给小麦高产、高效、无污染及可持续生产提供合理的氮肥运筹技术和理论依据,以烟农19为材料,在大田条件下,研究了不同施氮量和基追比例对土壤-小麦系统氮素积累及分配的影响。结果表明,施氮可提高0-100 cm土体内的全氮含量。在小麦越冬前,0-40 cm土层中NO3--N含量随氮肥用量和基肥比例的增加显著增加;起身期到拔节期,施氮量为180和240 kg.hm^-2且基肥∶拔节肥∶孕穗肥为3∶5∶2处理的0-40 cm土层内NO3--N含量下降,而施氮量为240 kg.hm^-2且基肥∶拔节肥为7∶3和5∶5的处理及施氮量为300 kg.hm^-2且基肥∶拔节肥为7∶3的处理则显著增加;拔节期到成熟期,随施氮量的增加,0-60 cm土层速效氮增加幅度有所提高。孕穗肥可明显提高灌浆期的植株全氮含量。因此,在240 kg.hm^-2施氮水平、基肥∶拔节肥∶孕穗肥为3∶5∶2条件下,施氮既能减少土壤硝态氮累积量,又能有效降低土壤硝态氮污染地下水的可能性。

The experiments were conducted from 2006 to 2008 at the farm of Anhui Agricultural University. Yannong 19 was used in this study. The effects of three nitrogen application amounts ranged from 180 to 300 kg.hm^-2 and three ratios of base and topdressing on nitrogen assimilation and distribution in soilplant system were investigoued. The main results were as follows： application of nitrogen fertilizer could increase total nitrogen content in 0-100 cm soil profile. The NO3 -N content in 0-40 cm soil layer increased significantly with the increment of nitrogen fertilizer dosage and ratio of basal nitrogen fertilizer at the wheat over-winter stage. The NO3^- N content in 0-40cm soil layer lowered for treatments L1, M1, while that of treatments M3, H2, H3 increased in 0-40 cm soil layer at middle growth stage. The NOB-- N content of depth layer increased obviously in 0-60 cm soil layer for three ratios of base and topdressing at the same nitrogen fertilizer dosage during middle and latter growth stage, especially under the high ni- trogen fertilizer level. The total nitrogen content of wheat plant before anthesis could be increased with the mount of basal nitrogen fertilizer increasing. In general, M1 （basal N fertilizer： jointing N fertilizer： booting N fertilizer=3 ： 5 ： 2） was the optimum nitrogen application model for 240 kg N.hm^-2, which only could decrease the possibility of nitrogen pollution to groundwater but also gained the best economy benefit.