移栽密度与供氮水平对水稻产量、氮素利用影响

Effects of Transplanting Density and Nitrogen Management on Rice Grain and Nitrogen Utilization Efficiency

探讨不同移栽密度和氮素供用水平对水稻产量、氮素吸收和利用的影响,为水稻生产的科学施肥提供参考依据。采用田间试验在3种栽培密度(30 cm×30 cm、40 cm×40 cm、50 cm×50 cm)和5个施氮水平(0、150、225、300、375 kg/hm2)条件下研究了水稻产量、产量构成因子及氮素吸收利用的差异。施用氮肥或增加密度,均可显著增加水稻产量;当施肥过量或密度较高时,产量降低。同一密度下,施氮量增加,水稻单位面积有效穗数、穗粒数、子粒、秸秆和总吸氮量先增加后降低;氮素收获指数相反;而氮素干物质生产效率、氮素稻谷生产效率、氮素农学利用效率、氮素利用效率与氮素偏生产力显著降低。相同施氮量下,移栽密度变大,单位面积有效穗数、氮素农学利用效率、氮素利用效率与氮素偏生产力呈增加趋势;总吸氮量先增加后降低。综合考虑产量、氮素利用及环境污染等因素,该地区水稻生产合理的栽培密度和氮肥施用量分别为40 cm×40 cm和150 kg/hm2。

The objective of this study was to explore rice yield,N uptake and utilization efficiency of different transplanting density to provide a foundation for scientifically fertilizer.Field experiments were conducted to study the various traits of yield components and N uptake and utilization under different rice transplanting density of 30 cm×30 cm,40 cm×40 cm,and 50 cm×50 cm with N application rates of 0,150,225,300 and 375 kg/ hm2 in purple soil of upland of Sichuan province in 2005.The results were as follows.Applying N fertilizer or improving transplanting density significantly increased rice yield,but as over-fertilizer or density,rice yield decreased.Under the same transplanting density,panicle-area,grain per panicle,total N accumulation,N uptake of grain and straw increased,and then reduced.And N harvest index decreased,and then increased.But N dry matter production efficiency,N grain production efficiency,N agronomic efficiency,N recovery efficiency,and N partial factor productivity significantly decreased.Under the same N rate,high transplanting density decreased panicle-area,N agronomic efficiency,N recovery efficiency and N partial factor productivity.But total N accumulation of grain and straw increased,and then decreased.Comprehensive the yield,N utilization efficiency and environment pollution,the recommendation of fertilizer N rate for rice was 150 kg/ hm2 and rational density 40 cm×40 cm in the experimental area.