水稻旱育秧的移栽密度对群体结构和光能利用的影响

Effect of Plant Density on Population Structure, Light Utilization by Seedlings of Rice Raised in Dry NurseryJournal of Zhejiang Agricultural University,1998,24(4):349～354

研究了早稻旱育秧不同移栽密度的群体结构、光能分布与利用特性及产量构成，结果表明：移栽密度较低时，群体的分蘖高峰期推迟，有效分蘖期延长，且旱育秧群体有较强的自动调节能力．双季早稻的适宜密度为２３．３ｃｍ×１３．３ｃｍ；孕穗期群体叶面积的垂直分布状况因移栽密度而异，１６．７ｃｍ×１３．３ｃｍ，２３．３ｃｍ×１３．３ｃｍ的叶面积以３０～４５ｃｍ层为最大，３０．０ｃｍ×１３．３ｃｍ的最大叶面积出现在４５～６０ｃｍ层；群体的漏光率随移栽密度的提高而变小，光能吸收率随太阳高度的增大而减小，随密度提高而增大．栽植密度２３．３ｃｍ×１３．３ｃｍ的产量显著高于１６．７ｃｍ×１３．３ｃｍ，２０．０ｃｍ×１３．３ｃｍ和３０．０ｃｍ×１３．３ｃｍ，这与其穗粒重协调发展有关．

The research was carried out at Zhejiang agricultural university experimental field Seedlings were raised in dry nursery and transplanted at five planting densities ie 167 cm×133 cm, 200 cm×133 cm, 233 cm×133 cm,267 cm×133 cm and 303 cm×133 cm The main results are as follows ① At lower planting density tillers per plant reach maximum later by 5-10 days, and the duration of actively tillering extends by 5-7 days in comparison with higher density Transplanting density of 233cm × 133 cm is most suitable in local condition. ②During spike formation stage,the vertical dispersion of leaf area is not the same for different planting densities For higher planting density (treatment D1) it forms “a toppled pagoda like shape”, for medium planting density (treatment D3) it forms “an upright pagoda like shape”, and for lower planting density (treatment D5) leaf area is markedly reduced ③Light energy distribution in conapy and utilization vary with planting density At high planting density solar energy absorption were greater but leaves at lower layers had weak radiation④As the density increases the extent of change in the solar reflection coefficient within a day also increases and light penetration rate decreases and the extent of change within a day is also reduced ⑤Yield in treatment D3 is significantly higher than those in treatments D1,D2 and D5