Hilly Farmland Nutrient Balance And Soil Nutrient Study

STUDY ON THE NUTRiENT BALANCE OF AGROECOSYSTEM AND SOIL NUTRIENT OF THE hILL ZONE OF SICIIUAN BASIN ZHANG Xizbou (College of Agriculture, Sichuaxi Agricultural University/Yaan,Sichuan,China 625014) Abstract Some county of the hill zone of Sichuan basin was selected according to three sub-ecosystems zone and six years nutrient of agroecosystem since 1985 was calculated. The nutrient balance of agroecosystem and the effect of nutrient balance on the soil nutrition were studied based on soil analysis. The results as follow: (1) N supply in all county of the hill zone of Sichuan basin was in large surplus since 1985. In all of the country, the average surplus ratios of Mingshan and Qianwei was less than 20%, others exceeded 40%. (2) The Phosphorus balance in all of the country was generally in deficit in 1985, but after 1990, it has the tendency of surplus and each of the country抯 ratios exceeded 40%. (3) Potassium balance in all of the country was generally in deficit since 1985 and the deficit ratios all exceeded 40%. (4) The Sulphur balance in all of the country was generally in deficit in 1985, but after 1990, with the increasing of use of Ca(H2P04)2 旽20, these deficit has the tendency of improve and showed a surplus.(5) The level of fertilizer use is high at present, according to the fact of the soil and paying attention to the ratios of each nutrient of fertilizer can not only increase the yield of crops, but also increase the contributions of fertilizer. (6) The decreasing of using organic fertilizer, large surplus of N, P and the serious deficit of Potassium, all these resulted decreasing of the content of organism and total Potassium in the soil and the increasing of the content of effective N, P, K and total N, P in the soil.