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运用空间统计学的模拟方法,以不同密度棉花群体为研究对象,对其冠层内光合有效辐射(PAR)的空间分布予以研究。通过拟合PAR透射率的半方差函数模型和绘制等值线图来反映不同密度群体冠层内PAR透射率的空间格局。利用克里格空间内插法和Simpson3/8法计算出盛蕾期棉花群体平均PAR透射率,分析其与LAI的回归关系,并对克里格插值法进行交叉验证。结果表明,冠层PAR存在强烈的空间自相关性,变异函数的最佳理论模型为高斯模型,决定系数均在0.9以上。各密度冠层PAR透射率具有相似的空间格局,但其变异程度有随密度增加而上升的趋势。群体平均PAR透射率与叶面积指数(LAI)呈指数回归关系,与前人研究结果一致。应用空间计学研究PAR空间分布格局,将有助于对PAR进行精确定位和定量化地估算,为作物科学配置和作物冠层结构调控提供理论依据。
Spatial statistical methods were used to study the spatial distribution of photosynthetically active radiation (PAR) in different density cotton populations. The spatial distribution of PAR transmittance in the canopy of different density groups was fitted by fitting the semi-variance function model of PAR transmittance and drawing the contour map. The average PAR transmissivity was calculated by Kriging interpolation and Simpson 3/8 method, and the regression relationship between LAI and LAI was analyzed. The Kriging interpolation method was used to verify the PAR transmission. The results showed that there was a strong spatial autocorrelation of canopy PAR, and the best theoretical model of the variogram was Gaussian model with coefficients of determination above 0.9. The transmissivity of PAR in each density canopy has a similar spatial pattern, but the degree of variation tends to increase as the density increases. The average PAR transmissivity and leaf area index (LAI) showed an exponential regression, consistent with previous studies. Applying the spatial statistic to study the spatial distribution pattern of PAR will help to accurately locate and quantify the PAR and provide a theoretical basis for crop scientific configuration and crop canopy structure regulation.