Fertility and Changes on Indices of Paddy Soils in Yongchun County

Five regular tests on 2,435plough layer soil samples from the paddy fields in Yongchun County,as well as the total N,P and K and available Ca,Mg,S,Zn and B in 400soil samples,were conducted and data collected for the analysis.The changes in nearly 30years on the soil's fertility and characteristic indices were evaluated.In reference to the provincial grading system,the paddy soils were acidic,the organic matters on average in the medium to high level,and the N and K supplies in the medium to low level,the available P rich,Mg and S in the medium to low level,the effective boron short or severely low,and the exchangeable calcium and zinc generally abundant.The contents of organic matters and total N have increased 27.9% and 32.1%,respectively,and the available P increased 4.1times since the Second Soil Survey.The paddy soils showed different degrees of acidification with a pH decreased from 5.4to 5.0on average.The information could be used as a guideline for appropriate fertilization in Yongchun County.