In order to understand the relationships between P fertilizer and crop yields in the rape-maize rotation system in southern hilly areas, the field trials were used to find out the effects of cropping patterns and P fertilizing amount on the crop yields of rape-maize rotation system and P loss. The results showed that P fertilizer increased the production of maize and rape significantly, and the yield of maize was increased by 18.46%-87.50%. The yield of maize applied with P fertilizer was very significantly higher than CK. The yield of rape applied with P fertilizer was increased by more than 32.0% compared with CK, and the yield increment of the optimized fertilization treatment was higher than the normal one. The coefficient of variation of the production of CK in the two season-crop could be the highest, which meant the stability of the production was the worst. The yields~ stability of rape treated by OPT （optimized fertilization＋ridge planting＋ straw mulching） and OPTP （optimized fertilization＋ridge planting＋ Straw mulching＋ Contour hedgerow） were the best, while the yields＇ stability of maize treated by OPTP was the best.
Guizhou Agricultural Sciences