施氮量和移栽密度对重穗型杂交稻产量及氮肥利用率的影响

Effects of N Application Rate and Plant Density on Grain Yield and N Use Efficiency of Hybrid Rice with Heavy Panicle

以重穗型杂交稻德优4727和轻穗型常规稻五山丝苗为材料,设置4个施氮量(0、120、165、210 kg/hm^2,分别记为N0、N120、N165、N210)和3种移栽密度(25.0、19.1、12.5丛/m^2,分别记为D1、D2、D3),于2016年在四川德阳进行大田试验,研究施氮量和移栽密度对重穗型杂交稻产量及氮肥利用率的影响。结果表明,参试水稻品种的适宜移栽密度均为25.0丛/m^2,在此移栽密度下,重穗型杂交稻德优4727产量随施氮量的增加呈先增加后下降的趋势,以N165处理产量最高(10.90 t/hm^2),轻穗型常规稻五山丝苗产量随施氮量的增加呈升高趋势,以N210处理产量最高(10.21 t/hm^2);相同移栽密度下,参试水稻品种氮肥利用率随施氮量的增加呈下降趋势;随移栽密度的增加,参试水稻品种产量和氮肥利用率呈增加趋势。可见,提高移栽密度,减少施氮量可兼顾水稻高产和氮肥高效利用,其最佳肥密组合为施氮量165 kg/hm^2、移栽密度25丛/m^2,即低氮密植可作为重穗型杂交稻高产高效栽培的关键技术。

A field experiment was conducted to study the effects of nitrogen （N） rate and plant density on grain yield and N use efficiency of hybrid rice Deyou 4727 with heavy panicle, and conventional rice Wushansimiao with light panicle, under four N application rate（0,120,165 and 210 kg/hm2, namely N0, N120, N165 and N210）and three plant densities （25.0, 19.1, 12.5 hills/m2, namely D1, D2 and D3）. The results showed that the 25.0 hills/m2 of planting density was the optimum planting density. When the planting density was 25.0 hills/m2, the grain yield of Deyou 4727 was increased with the increasing of N application rate at first and decreased after N application rate exceeding 165 kg/hm2, and the grain yield of Wushansimiao was increased with the increasing of N application rates. The highest grain yield of Deyou 4727（10.90 t/hm2） was in combination of N 165 kg/hm2 and 25.0 hills/m2. Wushansimiao obtained the highest grain yield（10.21 t/hm2）in the combination of N 210 kg/hm2 and 25.0 hills/m2. Under the same plant density, N use efficiency was decreased with the increasing of N application rates. Grain yield and N use efficiency was increased with the increasing of plant densities. It is a key technique for the high-yielding and high-efficiency cultivation of hybrid rice with heavy panicle. N application rate of 165 kg/ hm2 and plant density of 25.0 hills/m2 is the optimum combination.