Effects of surface soil salinity on crop yield in areas of the lower reaches of the Yellow River

By applying geostatistical techniques to a large-scaled area of the Bojili Irrigation District in Shandong, the regional surface soil salinity effects on crop yields were investigated. The tendency and features of the temporal and spatial variability of the surface soil salinity and crop yields were depicted and the impacts of the soil salinity on summer maize and winter wheat yields under the different combinations of soil, irrigation and fertilizing were quantitatively analyzed. The results showed that, within a full hydrological cycle year, the regional spatial varieties of the surface soil salinity and crop yields indicated different distribution features, while the temporal varieties of these properties demonstrated similar distribution tendency and features. The spatial varieties of the crop yields were significantly influenced by the corresponding distributions of the regional surface soil salinity, and the spatial distributions of the soil salinity values and crop yields in different seasons were relatively stable in the upper and lower areas, but varied significantly in the middle area of the irrigation district. The surface soil salinity showed a great effect on the winter wheat yields under the different combinations of soil, irrigation and fertilizing. With the same soil salinity and fertilizing levels, irrigation had a significant influence on the winter wheat yields, while with the similar irrigation level fertilization showed significant effects on the yields of both crops. The results of this study provided the rational data that will be of benefit to making the soil and water management strategies and crop patterns in this region.