Soil and Water Resources and Land Sustainable Productivity in the Catchment Area with Intensive Management in Hilly Red Soil Regions, China

摘要

Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of Hunan Province, the soil and water resources dynamics, fertility evolution characteristics and land productivity changing situation were studied. Fixed observation results from 1993 to 2002 showed that pools covering about 15% of total area could store up 10% of surface runoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio of interception and evapotranspiration in land, storage in pools ;and drainage was 7:2:1, which ensured the resources and nutrients equilibrium and a benign recycle in the catchment area system, and benefited the aquatic culture and helped to resist seasonal drought. Moreover, the results showed that soil erosion modulus decreased significantly, equal to or lower than soil loss tolerance (≤500 t km~(-2)) in reddish yellow soil regions. Soil organic matter, total and available N content in sloping land, dryland and paddy field increased steadily (>10%); water storage enhanced by more than 20% in sloping land and dryland in drought season; crop production increased by more than 20%; and production of trees, fruits, tea and fish as well as land productivity increased yearly.