Paddy Soil Fertility and Effects of NPK Fertilization on Middle-season Rice in Minqing County

4005paddy soils in Minqing county was used to assay the fertility, and which was compared with the second general soil survey, then the effect of NPK fertilization on middle-season rice was character by 3414 experiments from 2007 to 2012.The results showed that organic matter and available phosphorus accounte for88.44% and 75.21%, respectively.Available nitrogen and potassium accounted for 86.04% and 83.50%.Available calcium, sulfur and zinc were above middle, but the available magnesium and boron were scared.Compared with the results of second general soil survey, the proportion of acid soil increased and the organic matter and available nutrient content increased.The effect of NPK on middle-season rice were 20.5%、3.6% and 6.5%respectively, but it is different from results in the 1980s (N>P>K) .Our results suggest that lime will be used to adjust pH, organic fertilizer、nitrogen and potassium will be used to increased fertilizer, and phosphorus and medium trace element also will be used in middle-season rice in Minqing County.