Effects of Sowing Date on Yield of Dryland Maize in West Mountainous Region of Hebei Province

Using the Xingkang No.2 as the materials,two sowing date treatments were set including May 12(early sowing) and June 15(CK),the photosynthetic rates were detemined in maize-filling stage,the agronomic characters and yields were evaluated in harvesting stage,and the effects of different sowing dates on yield of dryland maize were studied in west mountainous region of Hebei Province with the contrast design.The results showed that stem diameter,ear row number,grain number per row and thousand kernel weight of early sowing were significantly improved,ear height and empty stalk were significantly decresed,finally production increased.Net photosynthesis rate of later sowing was increased by 5.7%than that of early sowing in maize-filling stage.The accumulation of net photosynthesis rate of early sowing was greater than that of later sowing in whole growth stages.Considering the seedling growth ensured,appropriate early sowing was more effective to increase the yield of maize.