Analyses of Affecting Factors for Spatial Distribution of Actual Crop Productivity in Songnen Plain

The main affecting factors concerning spatial distribution of maize and soybean actual productivity in Songnen Plain were studied.Controlling factors that affected the regional cropland productivity were found.Correlation analysis showed that the correlation index between maize actual productivity and the rainfall in growing seasons is the highest,the correlations between the productivity and the annual solar radiation and the average annual temperature are relatively lower.For the actual productivity of soybean,the correlation index with annual rainfall is the highest,the correlation with annual solar radiation is lower.The actual productivity of soybean shows negative correlation with average temperature.The actual productivities of maize and soybean under different slopes have no significant differences,which shows that for croplands in Songen Plain,slope is not an important factor affecting crop actual productivity.For different soils,the rank of actual productivity of maize is black soil,meadow soil,chernozem、 dark brown soil、saltierra and saltern,aeolian soil.For actual productivity of soybean,the rank is black soil,meadow soil,dark brown soil,chernozem、saltierra and saltern,aeolian soil.Divided by rainfall isoline of 500 mm,the actual productivity of maize and soybean in western part and eastern part of Songnen Plain were analyzed to find the variance.Results showed that,for actual productivity of maize and soybean,there is significant difference between the two parts.