Xiliaohe River watershed plays an important role in regional and national grain security.With the development of society and economy,water consumption that increased dramatically causes water shortages.Crop water requirement can provide quantitative basis for making regional irrigation scheme.In this study,spring maize water requirement is calculated by using PenmanMonteith formula and spring maize coefficient from May to September at 10 meteorological stations in Xiliaohe River watershed from 1951 to 2005.The variation trend of the spring maize water requirement during the whole growing stage,water requirement in every month,and meteorological influencing factors are obtained by using Mann-Kendall method,and the degree of grey incidence between the water requirement and meteorological influencing factors are shown.The results are the spring maize water requirement during the whole growing stages increases at half of the stations in Xiliaohe River watershed,and are remarkably affected by the water requirement in May.The monthly mean,maximum and minimum air temperature form May to September show an increasing trend in Xiliaohe River watershed in recent 55 years.The monthly mean and minimum air temperature increases notably.The relative humidity,precipitation,wind speed and sunshine show a decreasing trend with variety for different months.The monthly maximum air temperature,wind speed,sunshine and monthly mean air temperature have the highest correlation degree with spring maize water requirement from May to September.
