Effects of soil moisture in spring on growth of winter wheat in North China Plain

Crop growth can reflect the growth status of crops, soil fertility and plant nutrition. The winter wheat of North China Plain is facing a number of environmental problems that threaten the crops growth and yield, such as, water resource shortage. Therefore, this paper selected the North China Plain (NCP) as study area, analyzed the effects of soil moisture in spring on growth of winter wheat and to find the dominant factor affecting winter wheat growing. In this paper, the leaf area index (LAI) was selected as the growth indicator, and the correlation between LAI and soil moisture in spring was analyzed based on long time series half-month data (from 1982 to 2010). The results showed that the growth of winter wheat mainly showed positive-low-negative correlation with the soil moisture from early February to late April in the NCP. The growth of winter wheat and the soil moisture show a significant positive correlation in February, especially in the northern of the NCP. And in this period water was the dominant factor affecting winter wheat growing. But in the southern of the NCP (Anhui and Jiangsu province), water had little effect on winter wheat growth. In the NCP, the correlation between the LAI and soil moisture was low and the absolute value of correlation coefficient was mostly less than 0.3 in March. In April, the growth of winter wheat showed negative correlation with the soil moisture in most parts of NCP, in addition to the eastern part of Jiangsu province.