Study on the relationship between winter wheat sowing area changes and soil salinity in the typical area of the Yellow River Delta

【Objectives】 This paper tried to analyze temporal and spatial relationship between soil salinity and distribution of winter wheat, to explore soil salinity effect on winter wheat planting, and to supply scientific advice for winter wheat production decision. 【Methods】 Taking Kenli County,located in the Yellow River Delta, as study area, the winter wheat distribution information was extracted by decision tree model that was generated by analysis of the typical spectral curves with ETM images in April 2003, April 2008 and March 2013. Through spatial overlay of winter wheat planting distribution at each phase, the variation of winter wheat area and the distribution in recent 10 years were analyzed. Based on investigation and analysis of field soil salinity data, the relationship between winter wheat planting area changes and the soil salinity was analyzed. The distribution of winter wheat and the corresponding phase soil salinity distribution were spatially overlaid to compare and analyze the relationship of winter wheat and soil salinity distribution. Related attribute statistic was conducted correspondingly. At the same fince soil salinity distribution in 2008 and 2013 was overlaid, salinity changes have divided into salt reduced and increased area. Soil salinity distribution and the winter wheat planting area at same period were spatially overlaid to analyze the influence of soil salt content on the winter wheat distribution changes.【Results】 1)Winter wheat distribution has obvious spatial characteristics in Kenli County, mainly distributed in the southwest of Kenli and northeast coast of the Yellow River, with a consistent spatial distribution characteristics to low soil salinity zone. 2)The winter wheat planting area significantly reduced from 2003 to 2008 and slightly increased from 2008 to 2013 in Kenli County. 3)The winter wheat planting area change and soil salinity was extremely well correlated. In constant winter wheat planting area, soil salinity was concentrated in the 1.5-2.5 g/kg, in increasing planting area soil salinity focused on the 2-3 g/kg, and in winter wheat planting reduced area, the soil salinity was more than 3 g/kg. 4)The distribution change of winter wheat in 2008-2013 has a very high consistency with the otants of soil salinity. The planting areas of winter wheat in increased and unchanged area account for 98.07% in soil salinity reduced wheat area, and in the soil salinity increasing wheat area, winter wheat planting reduced area accounts for 84.54%.【Conclusion】 Winter wheat planting area is highly aftected by the change of the soil salinity. With increasing soil salinity, the winter wheat planting areas were rapidly reduced. The upper limit for winter wheat normal growth is 3 g/kg. The control of soil salinity is the key method to maintain and expand the scope of the winter wheat planting.