种植密度对玉米-大豆间作群体产量和经济产值的影响

Effect of plant density on population yield and economic output value in maize-soybean intercropping

采用二次饱和D最优设计,研究了种植密度对玉米-大豆间作群体产量和经济产值的影响,并建立了以玉米和大豆密度为变量,以间作群体籽粒产量、干物质积累和经济产值为目标函数的二元二次数学模型.模型解析表明：种植密度对玉米-大豆间作群体籽粒产量、干物质积累和经济产值影响显著,玉米密度对群体各指标的影响大于大豆密度.在低密度水平下,群体籽粒产量、干物质积累和经济产值均随密度的增加而增加.群体籽粒产量达到8101.31 kg·hm-2,最优措施组合为：玉米密度72023株·hm-2＋大豆密度99924株·hm-2;群体干物质积累达到15282.45 kg·hm-2,最优措施组合为：玉米密度75000株·hm-2＋大豆密度93372株·hm-2;群体经济产值达到23494.50元·hm-2,最优措施组合为：玉米密度73758株·hm-2＋大豆密度87597株·hm-2.通过计算机模拟得出,在本试验条件下,玉米-大豆间作群体籽粒产量≥7500kg·hm-2、干物质积累≥14250 kg·hm-2、经济产值≥22500元·hm-2的最佳密度组合为：玉米种植密度58554~71547株·hm-2,大豆种植密度82217~100303株·hm-2.

The effects of plant density on population yield and economic output value in maize and soybean intereropping were studied with the design of the double saturated D-optimal regression. A mathematical model was developed, in which the densities of maize and soybean were independent variables, and population grain yield, dry matter accumulation and economic output value were de- pendent variables, respectively. The result showed that the plant density significantly affected the population grain yield, dry matter accumulation and economic output value, and the effects of den- sity of maize on population indices were greater than those of density of soybean. Under the low level conditions of density, the population grain yield, dry matter accumulation and economic output value increased with the density of maize and soybean. The maximum population grain yield was 8101.31 kg · hm-2with the optimized combination of 72023 plant maize · hm-2 and 99924 plant soy- bean · hm-2, while the maximum population dry matter accumulation was 15282.45 kg · hm-2 with the optimized combination of 75000 plant maize · hm-2 and 93372 plant soybean · hm-2, and the maximum population economic output value was 23494.50 Yuan . hm-2 with the optimized combina- tion of 73758 plant maize · hm-2 and 87597 plant soybean · hm-2. The optimum combination of densities of maize and soybean calculated by computer were 58554-71547 plant ·hm-2 for maize and 82217- 100303 plant · hm-2 for soybean in order to obtain grain yield greater than 7500 kg · hm-2, dry matter accumulation greater than 14250 kg · hm-2 and economic output value greater 22500 yuan · hm-2 under the condition of this experiment.