Study On Temporal And Spatial Variation Of Rice Water Productivity Of Jiangsu Province Based On Remote Sensing And Meteorological Data

Food problem is a fundamental problem of global social stability. However, the lack of water resources and competitions between different industries make the share of agricultural irrigation water gradually deprived. So maximizing the water productivity of crop has become an effective way to solve the water problem. In this context, we estimated the rice water productivity (WP) of Jiangsu Province, from2004to2010, using the remote sensing technology as the main research tool. And analyze the variations of rice water productivity (WP) in time and space, expecting to provide theoretical support for the rational allocation of agricultural water resources and the sustainable development of agriculture.In this paper we used MOD09A1data, combining with the enhanced vegetation index (EVI) and surface moisture index (LSWI), to distinguish rice planting area. The paper established a rice spatialization model of yield, and extrapolated the rice yield statistics to a single pixel to get rice distribution maps. The actual evapotranspiration (ETa) of rice growing period was estimated based on a simplified model of the surface energy balance (SSEB) and P-M formula. According to the yield map and ETa map, the rice water productivity (WP) map was generated by the method of pixels compared one by one.Main achievements and innovations of this paper were as follow:1) On the basis of the mask of rice area, we built a space model according to the relationship between the maximum EVI in rice growth period and the rice yield of the corresponding unit, which extrapolating statistics yield to the pixel level. The model obtained intuitive spatial distribution maps of statistical yield data.2) Based on a simplified model of the surface energy balance (SSEB) and FAO-P-M formula, we estimated actual evapotranspiration in rice growth period. It solved the difficulty to estimate actual evapotranspiration because of the soil moisture stress, pests and diseases and other causes. We finally got the water productivity of Jiangsu province from2004to2010, which changed from1.17kg/m3to2.66kg/m3, with an average of1.81kg/m3.