氮肥和栽插密度对杂交稻“两优培九”产量及氮素吸收利用的影响

Effects of Transplanting Density and Nitrogen Fertilizer on Yield Formation and N Absorption in a Two-line Intersubspecific Hybrid Rice "Liangyoupeijiu"

以两系杂交稻两优培九为试材,研究不同N肥用量（纯N 0、112.5、225.0、337.5 kg/hm2）和栽插密度（22.5×104、27.0×104、31.5×104穴/hm2）对产量形成及N素吸收利用的影响.结果表明：（1）栽插密度对结实率和千粒重影响较小,对单位面积穗数和每穗粒数影响较大,在22.5×104～31.5×104穴/hm2的密度范围内,穗数与每穗粒数之间具有良好的互补性,因而产量差异未达显著水平.（2）N肥用量对每穗粒数影响较小,对穗数、结实率和千粒重影响较大,纯N用量为337.5 kg/hm2时,增穗作用不显著,反而极显著降低结实率和千粒重,导致减产.（3）稻株吸N量随供N水平的提高而增加,但植株含N率和N素累积量过高不利于叶鞘茎中的N素向穗部运转,降低籽粒N素积累量,导致结实率和千粒重显著下降而减产.（4）在中等肥力土壤上,施纯N 225.0 kg/hm2,栽插密度22.5×104穴/hm2,高峰苗控制在500.0万/hm2左右,有利于两优培九抽穗前茎鞘叶N素积累和抽穗后向穗部运转,能较好地协调穗数、结实率和千粒重的关系而获得高产.

A field experiment was conducted with different transplanting densities （22.5 × 104, 27 × 104 and 31.5 × 104 hole/ha） and nitrogen fertilizer rates （0, 112.5,225.0 and 337.5 kg/ha） using an intersubspecific hybrid rice, Liangyoupeijiu. The main results were as follows： （1） Influence of transplanting density on panicle per unit area and grain number per panicle was higher than that on seed-setting rate and 1000-grain weight. There was no significant difference in yield between treatments with transplanting densities ranging from 22.5 × 104 to 31.5 × 104hole/ha. （2） Effect of nitrogen fertilizer on grain number per panicle was lower than that on panicle number, seed-setting rate and 1000-grain weight. Seed-setting rate and 1000-grain weight were decreased significantly in the treatment with 337.5 kg/ha nitrogen fertilizer. （3） The amount of N-uptake was increased with the increment of nitrogen fertilizer rate. But excessive N-content and nitrogen accumulation were not of benefit to the transfer of nitrogen from vegetative organs （leaf, sheath and stem） to panicle, resulting in the reduction of N-accumulation amount in seeds, seed-setting percentage, 1000-grain weight and yield. （4） The better N accumulation of stem, sheath and leaf before heading, the better N transfer from stem, sheath and leaf to panicle after heading, the better coordinate relationship among panicle number, seed setting rate and 1000-grain weight and higher yield would be obtained under medium-fertihty field with nitrogen application of 225.0 kg/ha, transplanting density of 22.5 × 104 hole/ha and high peak seedlings of 500.0 × 104/ha.