不同氮肥处理对荞麦干物质积累、农艺性状及产量的影响

为探索陕甘宁黄土高原地区栽培荞麦高产最适施氮量,以甜荞品种——西农9976为试验材料,设置4个氮肥水平,2016年施肥水平为:0 (N0)、45 (N45)、135 (N135)和225kg/hm2(N225);2017年施肥水平为:0(N0)、90(N90)、180(N180)和270kg/hm2(N270),比较不同施氮量下荞麦产量和主要农艺性状,分析叶绿素含量和各器官干物质积累的动态变化规律。试验结果表明,不同氮肥处理均能提高荞麦的株高、一级分枝数、二级分枝数、单株花簇数、千粒重和单株粒数,使其产量显著上升;荞麦主茎叶片的叶绿素含量(SPAD)随施氮量增加先上升后降低;荞麦各器官干物质积累量与施氮量呈正相关,但在苗期和初花期,荞麦各器官干物质积累量随施氮量增加呈抛物线。因此,生产上建议陕甘宁黄土高原地区荞麦生长过程中投入180kg/hm2的氮肥,且注重施氮比例及时期,以此达到最佳的生产效益。

Effects of different nitrogen treatments on the dry matter accumulation, agronomic traits and yield of buckwheat

To investigate the optimum nitrogen application rate of buckwheat production for high yield in the Loess Plateau Region, a common buckwheat cultivar Xinong 9976 was used in a field experiment and the effects of different nitrogen fertilizer on the yield, agronomic traits, chlorophyll content and the accumulation of dry matter of buckwheat under four treatments were studied, i.e. no N fertilizer added 0 (N0), 45 (N45), 135 (N135) and 225 kg/hm² (N225) in 2016 and no N fertilizer added 0 (N0), 90 (N90), 180 (N180) and 270 kg/hm²(N270) in 2017. The results showed that four N fertilization treatments significantly increased the plant height, primary branch number, secondary branch number, number of flower clusters per plant, 1 000-grain weight and seeds number per plant, which led to a significant increase in yield. With the increase of Nitrogen rate, chlorophyll content first increased and then decreased. There was a positive correlation but a trend like a parabola in seedling stage and initial flowering stage between the accumulation of dry matter in various organs of buckwheat and the Nitrogen rate. Therefore, the optimum application amount of Nitrogen was 180 kg/hm², and more attention should be paid on different proportion and stage of Nitrogen application to ensure production benefit.