Spatial Forecasting Of Soil Salinity And It Application Based On GWR Model

The Yellow River Delta is located in the northeast of Shandong province, including Dongying city and Binzhou city as well as its neighboring cities and counties. It is one of the three major estuaries of China, and is known as the “Golden Triangle” which is because of huge economic potential. At present, the land resources of the Yellow River delta are abundant, but the land utilization rate caused by soil salinity is low, at the same time, the output benefit also has a deep influence on regional economy and ecological development. China’s State Council in 2009 officially approved the “Yellow River Delta Efficient Ecological Economic Zone Development Plan", marking the development of Yellow River Delta to become an important part of the national strategy for coordinated regional development.In this paper, I take the Yellow River Delta as the research area, the soil salinity field sampling data and the summer TM Landsat images of 2003, 2007 as data sources to study the spatial prediction effect of Geographic Weight Regression(GWR)model on the soil salinity, and to compare with other commonly used spatial interpolation methods. On this basis, the correlation between soil salinity and underground water level is discussed. Through the study, the following results can be obtained:(1)Compared to the linear regression model and Ordinary Kriging interpolation method, the GWR model takes into account both the spatial position of interpolation points and making full use of the environment factors in the model, adding environment factors as explanatory variables. In the spatial prediction of soil salinity in the Yellow River Delta, the prediction error of GWR model is small, the precision is high, the operability is strong, and the map is clearer. It is more suitable for promotion in the research area.(2)From 2003 to 2011, the soil salinity of the Yellow River Delta is gradually decreasing. The non-saline soil increased from 227.01km2 to 320.57km2. The weak saline soil increased from 553.12km2 to 779.56km2. The moderate saline soil decreased from 516.68km2 to 446.92km2. The severe saline decreased from 643.72km2 to 617.81km2 and the solonchak decreased from 396.80km2 to 222.47 km2. During the 9 years, the soil quality has improved obviously, and the ecological environment has been better.(3)From 2003 to 2011, there are some positive correlation between underground water level and soil salinity in the research area. But in some areas, due to the influence of other factors, the underground level may be negatively related to soil salinity. Such as the sea coast region, the effects of sea water on soil salinity are significantly greater than that of the underground water level. So there is a negative correlation between them. In addition, the fluctuation range of the underground water level in 2011 was smaller than that in 2003, but the high underground water level in 2011 spreaded wider.