红壤丘陵地区土地利用的生态学效应

Plant biomass and biodiversity,element accumulation and return,water loss and soil erosion,and changes in soil properties were studied for up to 10 years after conversiton of sparse tree-shrubby grass land into the following four land use patterns:masson pine(Pinus massoniana Lamb.) land,beautiful sweetgum(Liquidambar formosana Hance)land,vegetation reservation aldn,and artificial mowing land.Thie annual biomass production of the masson pine land was 5060kg ha^-1,being 4.9,2.1,and 6.0 times that of the beautiful sweetgum land,the vegetation reservation land,and the artificial mowing land,respectively,Compared with the background values,the number of plant species for the vegetation reservation and increased by 10 species after 10 years of land utilization,while for the masson pine and the beautiful weetgum decreased by 4,and for the artifiucial mowing land by 9.For masson pine land,total amount of N,P,K,Ca,and Mg needed for producing 1000kg dry matter was only 3.5kg,annual element return through litter was 22 kg ha^-1,both of which were much lower than those of the other patterns.Vegetation reservation was an effective measure to conserve soil and water and improve soil fertility in the red soil hilly region.Artificial mowing aroused serous degradation of vegetation and soil.Some measures and suggestions for management and exploitation of the red soil hilly region such masson pine planting,closing hills for afforestation,and stereo-agriculture on one hill are proposed.