Experimental Study On Dry Matter Partition Coefficient Of Summer Maize In North China

The conditions of the distribution of dry matter to stem, leaf and storage organ could be precisely expressed by dry matter distribution coefficient, which was the key parameter of driving maize growth and development model. As one of main producing areas of Chinese maize, North China was in extreme shortage of water resources,drought occurred extremely frequently, and serious damage was often caused to agricultural production. Therefore, field water controlling experiment was developed in North China, and the important meaning of maize dry matter distribution coefficient variation rules on guaranteeing the maize industrial development was studied. In this paper, the summer maize field water controlling experimental observation data conducted in Xiajin, Shandong Province, Gucheng of Hebei Province and Yuncheng of Shanxi Province was utilized for the continuous two years of 2013 and 2014, ratio method, linear regression and other amendment methods were adopted, and the complete maize biomass sequence was obtained within the whole growth period; on this foundation, the effective accumulated temperature simulated developmental process was taken as the independent variable, the dynamic variation model of summer maize dry matter distribution in North China was built at the sufficient moisture status, and the variation conditions of dry matter distribution coefficients of each maize’s organ in different developmental stages were discussed under moisture stress. The results indicated that:(1) The same time dynamic variation characteristics were shown among the maize dry matter distribution coefficients in three stations. Since seeding emergence, leaf’s dry matter distribution coefficient was starting to decrease continuously; stem’s dry matter distribution coefficient was increasing at first and then decreasing, the maximum value appeared before and after tasseling; spike’s dry matter distribution coefficient was increasing continuously after the tasseling of maize, which reached 1 20 d after tasseling,or dry matter was no long distributed to leaf and stem.(2) Within the growth duration of summer maize in North China, normalization was shown in leaf, stem and spike’s dry matter distribution coefficient at the sufficientmoisture status, and the segmented non-linear model could be used for simulation.10~15d after tasseling was the boundary of leaf’s dry matter distribution coefficient, the previous dry matter distribution coefficients could be simulated by using three times of polynomial dynamic model, and it was changed to 0 afterwards; 20~25d after tasseling was the boundary of stem’s dry matter distribution coefficient, the previous dry matter distribution coefficients could be simulated by using four times of polynomial dynamic model with the developmental process, and it was changed to 0 afterwards; spike dry matter distribution coefficient was calculated in the principle that the sum of leaf, stem,spike dry matter distribution coefficient at any development phase was 1. By testing results, it was demonstrated that in the sufficient moisture status, the simulation effects of summer maize dry matter distribution coefficient dynamic model in North China was favorable.(3) Under the influences of water stress, the variation trends of leaf, stem, spike dry matter distribution coefficient were not exactly the same in each developmental phase of summer maize developmental phase of North China. In the stage from seeding emergence to jointing, non-linear negative correlation was shown between maize leaf dry matter distribution coefficient and the relative moisture of soil, and 0.05 possibility level testing was passed; non-linear positive correlation was shown between stem dry matter distribution coefficient and the relative moisture of soil, and 0.05 possibility level testing was passed. Under the drought stress(the relative moisture of soil is less than 60%), dry matter distribution coefficient was obviously affected by the relative moisture of soil, and the dry matter distribution coefficient was basically unchanged when water regime was favorable. In the stage from jointing to tasseling, non-linear negative correlation was shown between maize leaf dry matter distribution coefficient and the relative moisture of soil, and 0.05 possibility level testing was passed; non-linear positive correlation was shown between stem dry matter distribution coefficient and the relative moisture of soil, and 0.05 possibility level testing was passed.Through two continuous years of field water controlling experiences conducted in three places of Xiajin, Gucheng, Yuncheng in North China, on the foundation of experimental data analysis and amendment, a set of complete summer maize leaf, stem dry matter distribution coefficient dynamic model in North China was established, and the calculation of the possibilities of dry matter distribution coefficient in any stage ofdevelopmental phase of maizes was realized. In the meantime, the variation rules of the dry matter distribution coefficient of each maize organ in different developmental phase were discussed under water stress, which proves references for related study of the maize growth and development model.