Effect of planting density on growth properties of rapeseed in wheat/silage rape multiple cropping

In this paper,a field experiment was conducted to study the dynamic effects of different sowing density on plant height,dry and fresh weight,leaf area index and net assimilation rate of rape seed in wheat stubble multiple rape cropping.The results showed that aboveground biomass accumulation can be described by S developing curve that was the seedling stage slower heightening and the buds stage quickest heightening and again slower heightening after blooming stage in wheat stubble multiple rape.Increasing sowing density significantly increased dry weight and fresh weight along with their daily growth rate of multiple-cropping rape with wheat,11.5 kg/hm2 sowing density was the optimal.Increasing sowing density obviously improved leaf area index and net assimilation rate of wheat stubble multiple cropping rape.Using mathematics equation simulated and compared the correlativity of rape growth stages and indexes in different sowing density,the results of simulated showed that dry weight was y=k/(1+aebx),and leaf area index was y=a+bx+cx2,other indexes all accorded with y=a+bx+cx2+dx3.The model simulation degree was all extremely remarkable.