华北地区夏玉米干物质分配系数的模拟

干物质分配系数是驱动玉米生长发育模型的关键参数。利用2013年、2014年连续两年在山东夏津、河北固城、山西运城进行的田间试验观测资料，采用比值法、线性回归等订正方法，获取完整的玉米全生育期内生物量序列；在此基础上，以有效积温模拟的发育进程为自变量，构建了华北夏玉米干物质分配的动态变化模型。结果表明：（1）三站玉米干物质分配系数有相同的时间动态变化特征。叶片干物质分配系数从出苗开始持续减少；茎秆干物质分配系数先增后减，最大值出现在抽雄前后；穗棒干物质分配系数在玉米抽雄后持续增加，抽雄后20d左右达到1，即干物质不再向叶茎分配。（2）华北夏玉米生育期内叶、茎的干物质分配系数均可用分段式非线性模型模拟。叶的干物质分配系数以抽雄后10～15d为界，之前干物质分配系数随发育进程可用三次多项式动态模型模拟，之后变为0；茎的干物质分配系数以抽雄后20～25d为界，之前干物质分配系数随发育进程可用四次多项式动态模型模拟，之后变为0；穗棒干物质分配系数通过依据任意发育阶段叶、茎、穗棒的干物质分配系数之和为1的原则计算求得。检验结果表明华北地区夏玉米干物质分配系数动态模型模拟效果良好。

Simulation on Dry Matter Distribution Coefficient for Summer Maize in North China

Dry matter distribution coefficient was a key parameter for driving maize growth model. Based on the field experimental data of two consecutive years (2013 and 2014) in Xiajin, Shandong province, Gucheng, Hebei province and Yuncheng, Shanxi province, the biomass sequence in the whole growth duration of maize was obtained by using the ratio method and linear regression correction method. On such a basis, the dynamic change model of dry matter distribution for summer maize in North China was established by taking the development stage of effective simulation of accumulated temperature as the independent variable. The results showed that: (1) There were same dynamic change characteristics for dry matter distribution coefficient of maize from three stations. The dry matter distribution coefficient for leaves kept reducing from seedling process, and the dry matter distribution coefficient for stems increased at the beginning and then decreased with the maximum value occurring at tasseling stage. The dry matter partitioning coefficient for ears increased after the tasseling and reached 1 after 20 days, which meant the dry matter was no longer allocated to leaves and stems. (2) Both dry matter distribution coefficients for leaves and stems of summer maize in North China could be simulated by piecewise nonlinear model. The dry matter distribution coefficient for leaves was distinguished at 10-15 days after tasseling, which could be simulated by three times polynomial dynamic model before tasseling along with the development process, and became 0 after tasseling. The dry matter distribution coefficient for stems was distinguished at 20-25 days after tasseling, which could be simulated by four times polynomial dynamic model before tasseling along with the development process, and became 0 after tasseling. The dry matter distribution coefficient for ears could calculated by the sum of the dry matter distribution coefficient for leaves, stems and ears, which was 1. The results indicated that the simulation effect of dynamic model for dry matter distribution coefficient of summer maize was proficient in North China.