棉花受棉铃虫为害后的补偿效应及其数学模型研究

本文采用四因子二次正交旋转回归组合设计的试验结果,建立了以籽棉产量、皮棉产量、单株成铃及单株产量为目标函数,考虑种植密度、果枝数、模拟被害蕾(7月上旬)和被害幼铃(8月上旬)四决策变量的数学模型。模型行为反应表明:低密度(小于2千株/亩)或高果枝数(大于16个/株)条件下棉花补偿能力衰退;被害蕾量的增加在一定范围内有增产作用;被害幼铃的变化对产量的影响较大;但相对来说,密度和果枝数是影响产量的两个主要因素。模拟计算表明:允许蕾被害584—656个/百株和幼铃被害187—225个/百株,并配以密度4360—4520株/亩和果枝数14.4—15.06个/株的措施,可获取亩产皮棉95公斤以上。最后给出了不同农艺措施下棉花的损害函数。

A MATHEMATICAL MODEL OF COTTON COMPENSATION FOR COTTON BOLLWORM DAMAGE

A regression design experiment,setting the unginned and ginnedcotton yield,mature boll number and cotton yield per plant as the tar-get functions,and in consideration of the cotton plant density,fruit branch number,removal numbers of squares and young boll(the simu-lation injuries of cotton bollworm in early July and early August re-spectively),as the decision variables,was conducted in cotton field inthe suburb of Handan City,Hebei Province.A quadratic four factorsmathematical model was established.The behavioral reaction of this model indicated that under lowdensity(<2000 plants/mu)or high fruit branch number(>16 branches/plant)onditions,the compensation ability of cotton declined.Thecotton yield increased in a certain range with the removal square number,but decreased obviously with the removal boll number.Relatively,theplant density and fruit branch number were the two main factors af-fecting on cotton yield.The prediction by the model showed that thetolerable number of damaged square is 584-656 squares/100 plants,andof damaged young boll is 187-225 bolls/100 plants.Keeping such toler-able levels,combined with the density range of 4360-4520 plants/muand fruit branch range of 14.4-15.6 branches/plant,the ginned cottonyield may attain to more than 95 kg.Finally,the damage functions ofcotton under different agronomic practices were presented.