Studies on Artificial Controlling Biosphere in Paddy Field and New Cropping System I. The Preliminary Report on Long-term Determination of Soil Fertility in Paddy Field

Continuous 5-year determination showed that,under the comprehensive reaction of various practices, the fish yield in artificial controlling biosphere maintained 3. 7t/ha, and its rice grain yield has also slightly increased to compare with traditional farming system in the condition which decreased 70% chemical fertilizer. The results of long-term determination demonstrated that, O. M, total N and total P in artificial controlling biosphere accumulated year by year, and higher than that in traditional farming plots. Furthermore, the soil fertility in pits and ditches is higher than field surface layer in the same plot. The supply of quick-acting nutrition from the soil of artificial biosphere plots characters high fertility and stability. It thus proved practically the posibility to realize sustainable agriculture with high yield, low consumption and pollution.