Studies On The Rule Of High Yield Formation Of Summer Maize In Hebei Province

Experiment was conducted in high-yielding field at Yi-an village, Gaocheng city, Hebei province during the year of 2008-2010. High-yielding summer maize varieties of Zhengdan 958, Xundan 20, and Fengyu 4 were used, and 3 densities, i.e. 79500, 82500, and 85500 plants per hectare were set to study the rule of high yield formation and the dynamic changes in maize growing and development. Some technique managements such as plant growth regulator and ridging method were also used to study the effect on maize root characteristics, as well as the maize plant. This study was of great meaning both in theory and practice for selecting appropriate planting density to forming high quality population to get high yield. The main results were as follows:1 There were some differences among maize varieties in dry mass accumulation and partitioning in different plant organs such as leaf blade, sheath and internodes. High-yielding maize had predominance in dry matter production after silking, and the high amount dry matter accumulation laid a good foundation for good quality and high yield of maize. The high LAI, long time and high speed of kernel filling during the filling stage was the key to acquire high yield.2 The competition between single plants was pricked up as the increase of plant density. Plant height increased with the increasing densities, while plant stem thickness, leaf area, and single plant weight decreased. High-yielding summer maize production should show good concern to the single plant as well as the population, tried to increase the performance in tolerant to adverse conditions. In order to get a maize yield more than 10500 kg per hectare, the variety should have a good ability in tolerant to high density, and the suitable plant density was around 82500 plant per hectare, and the planting pattern was equal row spacing of 60 cm in the low plain area of Hebei province.3 Under the same planting conditions the root weight, root length density, and stem thickness could be increased, the basal internodes could be shorted by using plant growth regulator (PGR). The root growth could be increased by PGR. Maize plant height was lower than control at 12 leaf stage when using PGR at 6 leaf stage. And the yield was increased to some extent compared with the control. Root characteristics of treated plants were better than control. The secondary root layers were 1.1 more than untreated plant.4 The root weight, root length density, and stem thickness could be increased, the basal internodes could be shorted by ridging cultivation accompanied to fertilizer top-drill at 12 leaf stage. Ridging cultivation could increase the secondary root amount and root branch numbers, and the good root activity was needed in nutrition and water absorption, and the ability for anti-lodging. Root characteristics of treated plants were better than control. The secondary root layers were 1.3 more than untreated plant.5 A reasonable and efficient population was the foundation for good quality and high-yielding maize production. To acquire high yield the following technique should be included: suitable spacing, optimized water and fertilizer management, suitable PGR treatment, ridging cultivation, and good plant protection. As the increase of planting density, the single plant turn week. The further study should focus on how to increase the anti-adverse ability from the basic soil foster and using the synthesis agriculture technology.