氮肥用量及基追比例对地黄生长发育和产量的影响

为了探讨优化氮肥管理对地黄的产量与品质的影响，通过2年的不同氮管理田间小区试验，比较不同管理条件下地黄干物质积累与氮素需求特征，通过不同氮肥用量试验确定氮肥调控总量，通过不同基追比例试验确定氮肥适宜施用时期，最终明确当前生产条件下地黄的氮肥优化用量及基追比例。无论是地黄总生物量还是氮素吸收量，积累高峰均出现在地黄拉线期至块根膨大期，干物质积累量高达0.86 g/(日?株)，氮素日积累量高达0.014 g N/(日?株)。增加氮肥施用量可明显增加地黄产量，最高可增产23%~29%。较氮肥基施相比，分次施氮可以明显增加地黄产量，基追比例3:7处理增产可达25%。当前生产条件，地黄优化氮肥用量为121~132 kg N/hm2，基追（拉线期）比例应为3:7。

Effect of Nitrogen Fertilization Rate and Ratio Between Basal and Topdressing on Growth and Root Yield of Rehmannia glutinosa Libosch

The aim was to study the effect of optimizing N management on root yield at harvest of Rehmannia glutinosa Libosch and quality. Two on-farm field experiments were conducted to evaluate dry-matter accumulation and N demand characteristics of Rehmannia glutinosa Libosch with different N management, to optimize N fertilizer application rate with different N rate experiments, and to determine optimal ratio between basal and topdressing fertilization with different base:topdressing ratio experiment. Whatever dry-matter and N uptake, the accumulation peaks occurred from root elongate to root enlargement. The highest dry-matter accumulation is 0.86 g/(day?zhu) from root elongate to root enlargement, and the highest N uptake is 0.014 g N/(day?zhu). The yield of Rehmannia glutinosa Libosch can increase by 23%-29% by optimal N application rate, compared to no N application. Compared to base N application treatment, the yield of Rehmannia glutinosa Libosch can increase by 25% with base: topdressing of 3:7 treatments. Across two years studies, the optimal N fertilizer rate should be 121-132 kg N/hm2, and 70% of total N fertilizer should be applied the fastest growing stage, such as root elongate phase.