Changes of soil nutrient contents and input of nutrients in arable of China

s: The changes of soil nutrient contents and input of nutrients in arable of China were analyzed according to the results of long?term measure of soil nutrient and recordation of fertilization in fixed location (National Soil Fertility Monitoring) from 1985 to 1997. The results showed that the rate of manure was decreased and the rate of chemical fertilizers was increased slightly. From 1985 to 1997, in fertilization plot, the contents of soil organic matter, available N and K were stable, available P was increased slowly, but in control plot, the contents of soil available P and K were decreased. The input and output balance of N and P was positive, but K was negative. From 1985 to 1995,the surplus of N was stable in dry land and south paddy field, and decreased in north paddy field, the surplus of P was increased slowly, and the negative balance of K was decreased in south paddy field, but increased in other fields.