乔化稀植苹果树冠投影的理论模型研究  

Theoretical model for predicting the shadow boundary of individual crown in sparsely planted apple orchard

作　　者：许华森 孙志梅[1] XU Huasen;SUN Zhimei(College of Resources and Environmental Sciences,Hebei Agricultural University,Baoding 071001,China)

机构地区：[1]河北农业大学资源与环境科学学院,河北保定071001

出　　处：《河北农业大学学报》2021年第3期41-46,95,共7页Journal of Hebei Agricultural University

基　　金：河北省高等学校科学技术研究项目(QN2020147).

摘　　要：农林复合系统光分布决定着该系统的功能和效应,模型是研究该系统光分布的有效手段,但目前仍然缺少能够模拟果农复合系统光照时空尺度分布的模型研究。本研究以黄土高原典型农林复合系统中的苹果树为研究材料,针对自由纺锤形(4年生)和疏散分层形(6年生)2种冠形的苹果树,推导出了树冠上任一点投影至地面的坐标方程;并将树干投影边界模型分为卵圆形函数、卵圆形方程和圆形方程构成的分段函数、圆形函数3种情况,建立了单株苹果树冠的投影边界模型。在消除半影效应后,4年生和6年生苹果树的阴影边界模拟值与实测值之间的决定系数均大于0.76,树冠投影面积计算值与实测值决定系数均大于0.938,表明该模型可较精确地描述苹果树冠的地面投影。研究结果证明该模型能够用于树冠的林下光照分析,并可在稀植苹果园遮光邻体对林下光照时空分布的进一步研究中发挥作用,为林下太阳辐射强度预测和确定林下作物适宜种植区域提供理论依据。The interspecific relationship determines the functions and benefits of agroforestry system.However,there remain to be lack of simulations taking into consideration of light distribution dynamic in spatial and temporal levels in agroforestry.To solve this question,the spindle shape and evacuation stratified shape of apple tree canopy was selected as research materials.We developed a three-dimensional coordinate system,which could show the projection position of any point of tree canopy.The projection position of key canopy points were used to establish a projection boundary model of individual tree with three scenarios,i.e.oval model,circular model,combining graphic model of oval and circular.After eliminating the penumbral effect of tree-shading,coefficients of determination between measured and calculated values of projection boundaries of 4-and 6-year-old apple trees were greater than 0.76.The coefficients of determination between measured and calculated values of the projection area of 4 and 6-year-old apple trees were greater than 0.938.The developed mathematical model in this study can accurately simulate the actual canopy shade range.Furthermore,this model would apply to analysis of the shading neighbors and its influences for understory crops,evaluate the solar radiation intensity under tree canopy,and determine the appropriate intercropping area of understory crops.

关 键 词：果农间作系统 冠形 树冠投影边界 树冠投影面积 半影效应 

分 类 号：S141[农业科学—肥料学]