冬小麦氮素吸收及产量对喷灌施肥均匀性的响应

 为了为喷灌均匀系数设计标准的制订提供更充分的依据，分别于2002~2003和2003~2004年度在北京进行了喷灌施肥均匀系数和施肥量对冬小麦氮素吸收量和产量影响的田间试验。试验中生育期平均喷灌均匀系数变化范围为72%~84%。除了基肥外，其它肥料利用喷灌系统施入，生育期平均喷灌施肥均匀系数变化范围为71%~85%，喷灌施肥量的变化范围为0~180kgN/hm2。试验结果指出，在所研究的均匀系数范围内，均匀系数对氮素吸收量和产量的影响不明显。施肥量对冬小麦产量的影响不明显，但秸秆全氮含量和氮素吸收量均随施肥量的增加呈现出增加趋势。本研究结果表明，对华北平原的冬小麦喷灌来说，目前我国采用的喷灌均匀系数不小于75%的设计标准不会对氮素吸收量和产量造成负面影响。

Responses of Nitrogen Uptake and Yield of Winter Wheat to Nonuniformity of Sprinkler Fertigation

Field experiments were conducted to investigate the effects of nonuniformity of sprinkler fertigation and the amount of fertilizers applied through fertigation on nitrogen uptake and crop yield during two growing seasons of winter wheat from 2002 to 2004 at an experimental station in Beijing. In the experiments the seasonal averaged Christiansen irrigation uniformity coefficient (CU) varied from 72% to 84%. Except for the fertilizer applied before planting, fertilizer was applied with the sprinkler irrigation system with a seasonal averaged CU for fertigation varied from 71% to 85%. Three levels of fertilizer applied varying from 0 to 180 kgN/hm2 were used in the experiments. The experimental results demonstrated that sprinkler fertigation uniformity had insignificant effects on nitrogen uptake and crop yield for the uniformity range tested. Also, the influence of fertilizer applied through sprinkler fertigation on crop yield was minor, while total nitrogen content for stem and nitrogen uptake increased with increasing fertilizer applied. Consequently, field experimental results obtained from this study supported that the target sprinkler uniformity of CU ≥ 75% suggested by the current national standard is high enough for minimizing the negative effects of nonuniformly applied water and fertilizers on nitrogen uptake and crop yield.