玉米/大豆套作体系中大豆茎秆生长过程模拟

摘要

为建立套作系统中大豆(Glycine max)茎秆生长过程的模拟方程,本研究以玉米(Zea mays)/大豆套作为对象,单作大豆为对照,3种不同株型大豆(南豆032-4、南豆12、九月黄)为材料,对两种种植模式下大豆茎秆生长进行定量化模拟.运用Richards方程[y=α/(1+pe-γx)1/δ],构建大豆茎长、茎粗生长变化的动态模型,方程参数α值(终极生长量参数)为各品种遗传参数,β值(初值生长量参数)、γ值(生长速率参数)和δ值(形状参数)在不同栽培模式、品种间变异较大,可见主要通过调节参数β、γ、δ值来实现对整个方程的调控.采用Logistic方程[y=α/(1+βe-γx)],构建大豆茎秆干重动态模型,β、γ值在不同栽培模式、品种间变异较大,主要通过调节参数β、γ值来实现对整个方程的调控.因此分别建立套作和单作栽培模式下的大豆模拟方程,构建大豆茎秆长、茎秆粗的生长动态模型,以及构建大豆茎秆干重积累的动态模型,所建立套作和单作生长模型方程精确度(R2)均在0.99以上.检验结果表明,模型对不同类型大豆材料在单套作体系下茎秆节间长度、粗度、干重都能很好的预测,能较好地拟合茎秆生长动态.本研究结果对探究玉米/大豆套作体系下大豆茎秆生长规律研究,具有一定的生物学意义.%The intercropping of maize and soybean is practiced in several parts of the world.Using models for forecasting soybean growth is a good cropping technique;however,few research models are available that predict soybean growth in monocropping and intercropping practices.This study was based on the systematic observations of Nandou 032-4,Jiuyuehuang,and Nandou 12.The growth of soybean stems can be quantitatively simulated by the patterns of growth in monocropping and intercropping cultivation modes.A dynamic model was established using Richards equation for model building,where the time step was represented by the physiological development time (PDT),describing the elongation of soybean stem internodes and the enlargement of the dynamic processes at the internodes,in monocropping and intercropping practices.In the dynamic model,the time step was estimated by the growth and development taking place on the actual number of days by logistic equations,for predicting the dry weight of the soybean stem in monocropping and intercropping cultivation practices.From the model,the potential length and thickness of the internodes gradually increased as the number of soybean internodes increased and reached a maximum at the ninth and seventh internodes,respectively,and then gradually decreased.Therefore,the potential length of the ninth internode and the potential thickness of the seventh internode were identified as the potential genetic parameters that can be used to calculate the potential length and thickness of other internodes.At the same time,the potential dry weight of the stem was used to determine the potential dry weight of other stems.The inspection results showed that different varieties of soybean have different cultivation patterns.The model reflected a satisfactory prediction rate.This model,developed using soybean varieties having different modes of cultivation,internode lengths,internode thicknesses,physiological development times,and dry weights of the stem,has good predictability and reliability,and the stem growth dynamics predicted by the model conformed well to the biological rules of stem growth,highlighting the biological significance of the model.