| Based on analyzing the amount of water consumption of winter wheat field of the typical incomplete Yuan “DongzhiYuan” of loess plateau,the content of the soil moisture in different periods and its relation with precipitation,amount of water consumption and wheat yield,discovery was made of the characteristics of change of wheat field soil moisture and its effect on agricultural production in the Yuan area of the loess plateau in east Gansu Province.The result showed that the source of water consumption is mainly from natural precipitation. When there is sufficient precipitation,the water consumption is great and the yield is high,and the annual soil moisture can be supplemented effectively.The highest yield may not be obtained in the year with most precipitation,but the lowest yield must be in the year with least precipitation.The plentiful precipitation in the previous year and sufficient soil moisture storage can effectively prevent spring drought of the coming year,which is the foundation for a bumper harvest of winter wheat.Likewise,even when soil moisture is insufficient,so long as precipitation is sufficient in the right time in spring,a good harvest can also be made.But if the drought happens continuously in the previous autumn and the coming spring,it must cause a bad drop of yield. |