密度对夏玉米干物质积累的影响及其归一化模拟模型的建立

在小区试验条件下,以新玉9号和中糯301为材料,设6个种植密度(13.5万、11.25万、9万、6.75万、4.5万和2.25万株/hm2),测定其干物质积累动态和产量,分析密度对夏玉米群体干物质积累的影响,并建立积温变量的干物质积累动态模型。结果表明,南疆夏玉米前期干物质积累速度快、积累量较高而后期积累速度慢、积累量较少。种植密度越大,干物质积累的最大增长速率越大,但其高值维持的时间越短,不利于子粒灌浆。中糯301较新玉9号对种植密度反应敏感,分别在9万株/hm~2和11.25万株/hm~2时产量最高。建立了基于归一化的苗后积温为变量的相对DMA预测的Richards方程:y=1.052 1/(1+e~(1.075 7-6.222 5x))~(1/0.089 0),R~2=0.991 4,模拟准确度为0.967 6~1.022 7,精确度在0.965 0**~0.993 8**,具有较好的模拟效果。

Effect of Density on Dry Matter Accumulation of Summer Maize and Establishment of Normalized Simulation Model

In the plot experimental conditions, Xinyu No.9 and Zhongnuo301 as the material, and 6 densitiese (135 000, 112 500, 90 000, 67 500, 45 000 and 22 500 plants/ha) of summer maize were set to determine the dynamics of dry matter accumulation and yield, for the arm to analyze the effect of density on dry matter accumulation of summer maize population, and establish the dynamic model of dry matter accumulation taking accumulated temperature as variable. The result showed that, the accumulation rate of dry matter in summer maize in southern Xinjiang was the fast, the accumulation rate was high, but the accumulation speed was slow and the accumulation amount was less. The greater the density, the greater the growth rate of dry matter accumulation, but the shorter the duration of high value, which is not conducive to grain filling. Zhongnuo301 was more sensitive to density reaction than the Xinyu No.9, and the highest yield was obtained at the density of 90 000 plants/ha and 112 500 plants/ha, respectively. The Richards equation based on the normalized DMA of the accumulated temperature after seedlings, y=1.052 1/(1+e^{1.075 7-6.222 5x}) ^{1/0.089 0}, R²=0.991 4, was established, whose simulation accuracy being 0.967 6-1.022 7, the precision between 0.965 0^**-0.993 8^**, so had a good simulation results.