The Analysis Of Crop Water Content Change Over The Songnen Plain In Growing Season During The Period 2000~2013

In the process of photosynthesis, water is one of the irreplaceable and an indispensable raw material. Crop water content is one of the main factors in plant photosynthesis, and has a great significance for the growth of crops. In this paper choose the Moderate Resolution Imaging Spectroradiometer(MODIS) 500 m reflectance dataset is used for the retrieval of crop water content over the Songnen Plain during the period 2000-2013. With Global Vegetable Moisture Index(GVMI) which has higher correlation and stability with crop water content to retrieval of crop water content of Songnen Plain in the growing season during the period 2000-2013, then analyzed the temporal and spatial change characteristics and the reasons. The results showed that:(1) The crop water content of Songnen Plain during the period 2000-2013 showed a trend of significant growth. The mean value of Songnen Plain growing season crop water content during the period 2000-2013 is 378.54g/m2. The crop water content of 2012 is the highest, 2000 is lowest. The difference between the maximum value and minimum value is larger. The change of month crop water content is basically same with the change of the crop water content during the period 2000-2013, showed a trend of significant growth with the crop. The crop water content of August is the largest, May and October is the lowest.(2) The crop water content is uneven distribution in Songnen Plain, and showed a trend of significant growth. The 87.60% of the cultivated land area growth trend is obvious, and showed a decreasing trend with smaller area. The west is higher than the others, and the west variable coefficient of crop water content is higher than the east.(3) The crop water content of the cities in Songnen Plain during the period 2000-2013 shows a trend of significant growth, as the Songnen Plain. The administrative area of Songnen Plain growing season crop water content distribution and variation shows a clear regional. The cities in eastern of Songnen Plain is higher than the western. The growing season crop water content of Changchun city is the largest, Baicheng city is the lowest. The minimum value of the cities is mainly distributed in 2000, maximum value is in 2012.(4) The growing season coin water content of the Songnen Plain during the period 2000-2013 shows a trend of significant growth, as the growing season crop water content of Songnen Plain. The administrative area of Songnen Plain growing season coin water content distribution and variation shows a clear regional. The cities in eastern of Songnen Plain is higher than the western.(5) Precipitation has a certain influence on crop water content of cities in Songnen Plain, and has regional. The less precipitation in the western Songnen Plain, the precipitation amount is larger, the influence on crop water content is good; on the contrary, the correlation is poor. The precipitation is positively related to the monthly mean of Songnen Plain growing season crop water content, June had a significant positive correlation, while the other months of the poor correlation with unobvious lag.(6) The temperature effect on crop water content of cities in Songnen Plain has the latitude zonality. The higher temperature region of Songnen Plain, the temperature effect on crop water content is larger, the correlation is better, on the contrary, the lower temperature region, the temperature has little effect on crop water content, the correlation is poor. The crop water content has a poor correlation with the temperature, but did not pass the significance test. The October has the largest correlation coefficient, the May is the lowest.