Effects of sowing date on growth, yield formation and water utilization of spring maize.

A field experiment of two planting dates and two genotypes Zhengdan958 and Ludan984 was carried out to compare crop growth,yield formation and water utilization of different planting dates.The results showed that LAI,dry matter and grain yield of two genotypes planted on May 15 were higher than those on April 24.There was no significant difference between genotypes.Planting in May 15 increased the yield.Difference of 1 000-grain weight between two planting dates and genotypes were not significant.The difference of grain number was not significant be-tween two genotypes,but was significant between two planting dates.The grain number of spring maize planting at the second planting date was increased than the first planting date.Water consumption and water utilization efficiency of the second planting date was higher than the first sowing date.In this experiment,the LAI of the second planting date was higher than the first one,which promoted dry matter accumulation and increased kernel numbers.Therefore,veg-etation growth of early planting date of spring maize was limited leading to yield decline should be considered.