杂交棉LAI动态特征的密度效应

【目的】研究棉花不同密度群体叶面积系数(LAI)特征参数的密度效应,应用作物高产群体相对LAI动态普适模型方程y=(a+bx)/(1+cx+dx²)模拟分析不同密度对LAI动态特征参数的影响。【方法】选用不同基因型杂交棉品种兆丰1号(陆陆杂交F₁代)和新陆中31号(海陆杂交F₁代)为供试品种,2016年4月22日播种。膜下滴灌栽植配置(10+66+10+66+10+66)cm,1管3行模式。设置8个种植密度处理(按收获株数),分别是7.20×10⁴、10.24×10⁴、13.14×10⁴、16.58×10⁴、19.62 ×10⁴、22.26×10⁴、24.70×10⁴和28.80×10⁴株/hm²(分别记为T1、T2、T 3、T 4、T 5、T 6、T 7、T 8),随机区组排列,重复3次,每区种植3膜18行,面积74.8 m²。【结果】棉花群体最大LAI在7.2×10⁴~28.8×10⁴株/hm²范围内随密度增加呈近似直线增大趋势,而最大LAI出现的时间随密度增加而提早;将LAI数据相对化处理后,不同密度群体的LAI差异在最大LAI之后较之前表现明显,高密度群体较低密群体LAI衰减迅速。全生育期平均LAI随密度增加呈显著线性增大趋势。密度对模拟方程各参数均有不同程度的影响。全生育期群体LAI变化速率呈“N”形变化趋势,且与群体LAI变化及生育期对应,高密度群体LAI增加及衰减的速率均大于低密度群体。【结论】密度对棉花全生育群体LAI动态具有显著的调节作用,尤其群体LAI变化速率、最大LAI及其到达的时间、平均LAI等重要特征参数对密度响应较为敏感,可作为对棉花群体密度调控的参考指标。

Study on Density Effects of LAI Dynamic Characteristics in Hybrid Cotton

【Objective】 In order to further clarify the density effect of (LAI) characteristic parameters of leaf area coefficient of cotton populations with different densities, the effects of different densities on the dynamic characteristic parameters of LAI were simulated and analyzed by using the relative LAI dynamic universal model equation y = (a+bx) / (1+cx+dx²) of high yield populations. 【Method】 Different genotypic hybrid cotton varieties Zhaofeng No.1 (land and land hybrid F₁ generation) and Xinluzhong 31 (sea and land hybrid F₁ generation) were selected as testing varieties and sown on April 22. Planting arrangement of drip irrigation under plastic film (10+66+10+66+10+66)cm, 1 tube 3 mode. Eight planting density treatments (according to the number of harvest plants) were set up, which were 7.2 ×10⁴ plants/ hm², 10.22 ×10⁴ plants/ hm², 13.14 ×10⁴ plants/ hm², 16.58 ×10⁴ plants/ hm², 19.62 ×10⁴ plants/ hm², 22.26 ×10⁴ plants/ hm², 24.70 ×10⁴ plants/ hm², and 28.80 ×10⁴ plants/ hm² (denoted as T1, T2, T 3, T 4, T 5, T 6, T 7, T 8, respectively), arranged in a random area group and repeated three times, and 3 films of 18 lines were planted in each area, with an area of 74.8 m². 【Result】The maximum LAI of cotton population increased approximately linearly with the increase of density in the range of 7.2×10⁴-28.8×10⁴ plants/hm² , showing an approximate linear increasing trend, while the time when the maximum LAI appeared was earlier with the increase of density; After the relative processing of LAI data, the LAI difference of different density populations was more obvious after the maximum LAI, and the LAI attenuation of high density population was faster than that of low density population. The average LAI of the whole growth period increased linearly with the increase of density. The density had different effects on the parameters of the simulation equation. The change rate of LAI in the whole growth period showed the trend of "N" shape, and corresponded to the change of population LAI and the growth period, the increase and attenuation rate of LAI in high density population was higher than that in low density population.【Conclusion】 Density plays an important role in regulating the dynamics of LAI in cotton whole growth population, especially in regulating groups LAI. The maximum LAI and its arrival time, average LAI and other important characteristic parameters are sensitive to density response, which can be used as the reference index of cotton population density regulation.