Investigation and analysis on soil fertility of cultivated farmland in Hai''''an County,Jiangsu Province
江苏省海安县耕地土壤肥力定位调查与分析

Nearly 1000 fixed positions were investigated and analyzed in Hai'an County,Jiangsu Province.The results show that the cultivated soil organic matter,total N,available P,available K increase by 9.8%,7.4%,190% and 18.3% respectively,higher than those in 1991,and by 41.3%,31%,245.2% and 18.6% respectively,higher than those in 1982.The soil physical and chemical properties are improved greatly.The evolution of soil fertility is related to the coordinate development in planting,breeding and processing,manuring of a great quantity of organic fertilizer,spreading of balanced fertilization technique,and optimizing of planting system and tillage mode in the county.