Discussion on Role of Forest to Control Agricultural Non-Point Source Pollution in Taihu Lake Basin-Based on Source-Sink Analysis

Taihu Lake is located at the center of Changjiang delta region, the Lake and its effluent rivers are important water sources for 40 million around inhabitants and rapidly increasing industrial factories in Shanghai, Ji-angsu and Zhejiang. The pollutants originate mainly from acidy rain, home sewage of the vast number of inhabitants, livestock manure, agricultural fertilizers & pesticides applied over fields in the drainage basin, and the industrial sewage. Due to the kinds of pollutants, the Lake water is getting highly eutrophic, with frequent blooms of blue-green algae. Compared with point-source pollutants, diffuse pollution is much com-plicated and difficult to control. Thus combating non-point pollution (NPP) is paid much great attention. Based on analysis on source-sink of NPP in Taihu Lake basin, it is concluded that the function of forests on NPP control is multiple and important by both source reduction and sink expansion. The primary objective of planting trees through constructing forested wetlands and establishing riparian forest buffers is to control soil & water erosion, decrease agrochemicals application, and improve farming conditions in the region of Taihu Lake basin. Moreover forests help to intercept acidy rain, protect streambanks, uptake nutrients, hold up pollutants and provide habitat for wildlife.

Biomass Production of Poplar Plantation Ecosystem in Yangtze River Beach Land

Currently, China is home to more than four million hectares of oil plants nationwide, and 154 kinds of energy trees could produce seeds containing more than 40 percent of oil, with total production of the seeds totaling five million tons. Another 57 million hectares of waste land are available and suitable for planting trees for the production of forest-based bioenergy, of which there is 630,000 hm2 beach land in the middle and lower reaches of Yangtze River where is suited for poplar growing. In order to approach the potential of poplar biomass production, the test was conducted in the paper. The result indicated that in the poplar forest ecosystem the herbaceous biomass production was 15.554 t/hm2. While biomass production for trees was 43.164 t/hm2, totally in the poplar plantation ecosystem biomass production reached 58.718 t/hm2. As well, poplars growing added incomes for local farmers.

Soil enzyme activities and their indication for fertility of urban forest soil

To reveal the biological characteristics of urban forest soil and the effects of soil enzyme on soil fertility as well as the correlation between physicochemical properties and enzyme activities,44 urban forest soil profiles in Nanjing were investigated.Basic soil physicochemical properties and enzyme activities were analyzed in the laboratory.Hydrogen peroxidase,dehydrogenase,alkaline phosphatase,and cellulase were determined by potassium permanganate titration,TTC(C_(19)H_(15)N_(4)·Cl)colorimetry,phenyl phosphate dinatrium colorimetry,and anthrone colorimetry,respectively.The result showed that soil pH,organic carbon(C),and total nitrogen(N)had great effects on hydrogen peroxidase,dehydrogenase,and alkaline phosphatase activities in 0–20 cm thick soil.However,pH only had great effect on hydrogen peroxidase,dehydrogenase,and alkaline phosphatase activities in 20–40 cm thick soil.Hydrogen peroxidase,dehydrogenase,and alkaline phosphatase were important biological indicators for the fertility of urban forest soil.Both in 0–20 cmand 20–40 cmsoil,soil enzyme system(hydrogen peroxidase,dehydrogenase,alkaline phosphatase,and cellulase)had a close relationship with a combination of physicochemical indicators pH,organic C,total N,available K,available P,cation exchange capacity(CEC),and microbial biomass carbon(C_(mic)).The more soil enzyme activities there were,the higher the fertility of urban forest soil.