The Taihu Region in eastern China is one of China's most intensive agricultural regions and also one of the economically most developed areas. High nitrogen balance surpluses in the summer rice-winter wheat double...The Taihu Region in eastern China is one of China's most intensive agricultural regions and also one of the economically most developed areas. High nitrogen balance surpluses in the summer rice-winter wheat double-cropping systems are leading to large-scale non-point source pollution of aquifers. In an interdisciplinary approach, four-year (1995-1998) field trials were carried out in two representative areas (Jurong County and Wuxi City) of the Taihu Region. Five farmers' field sites were chosen in each of the 2 locations, with each site divided into 'standard' (farmers' practice) and 'reduced' (by 30%-40%) N fertilization. For both fertilization intensities, N balance surpluses and monetary returns from grain sales minus fertilizer expenditures were calculated in an economic assessment. Based on the field trials, the mineral N fertilizer application rates reduced by about 10% for rice and 20%-30% for wheat were recommended in 1999. Since 1999, the research focused on the trends in N fertilizer application rates and changes in grain and agricultural commodities prices.Summer rice N fertilizer use, in Wuxi City as of 2001, dropped by roughly 25%, while for winter wheat it decreased by 10%-20%, compared to the 1995-1998 period. This has been achieved not only by grain policy and price changes, but also by an increased environmental awareness from government officials. Nitrogen balance surpluses in Anzhen Town (of Wuxi City) have consequently diminished by 50%-75% in rice and by up to 40% in wheat, with reductions being achieved without concomitant decreases in physical grain yields or returns from sales minus fertilizer costs.展开更多
Based on a comprehensive analysis on various classifications of natural resource values,this paper summarizes an ecological services system of constructed wetland(CW) ecosystems for the accounting of ecological econom...Based on a comprehensive analysis on various classifications of natural resource values,this paper summarizes an ecological services system of constructed wetland(CW) ecosystems for the accounting of ecological economic value.With the research,the wetland ecosystem services can be classified into six categories,that is waste treatment,food and material production,water supply,gas regulations,disturbance and water regulations,habitat and refuge provision.For decision making in terms of environmental economics for wetland construction,ecosystem services value for the wetland in Suzhou Taihu Lake National Tourist and Holiday Resort is accounted for 7,088,769 USD/yr through Environmental Economics Analysis.Ecosystem services value of waste treatment is 825,000 USD/yr,that of food and material production is 1,430 USD/yr,that of water supply is 4,752,000 USD/yr,that of gas regulation is 2,251USD/yr,that of disturbance and water regulations is 1,3721 USD/yr,and that of habitat and refuge provision value is 1,494,367 USD/yr.The ecosystem services values of a pilot constructed wetland in Suzhou are compared with those of other wetlands as a mean and of a typical human-interfered wetland in Wenzhou of China.Results show that in both finite and infinite time horizons considered,the wetland in Suzhou Taihu Lake National Tourist and Holiday Resort has the largest services value.This paper analyzes all the probability that may weaken the value of the Suzhou Taihu Wetland in order to provide some advices for the wetland protection.展开更多
基金Project supported by the Volkswagen-Foundation, Germany (No. Ⅱ/69 948) the Institute of Soil Science, Chinese Academy of Sciences.
文摘The Taihu Region in eastern China is one of China's most intensive agricultural regions and also one of the economically most developed areas. High nitrogen balance surpluses in the summer rice-winter wheat double-cropping systems are leading to large-scale non-point source pollution of aquifers. In an interdisciplinary approach, four-year (1995-1998) field trials were carried out in two representative areas (Jurong County and Wuxi City) of the Taihu Region. Five farmers' field sites were chosen in each of the 2 locations, with each site divided into 'standard' (farmers' practice) and 'reduced' (by 30%-40%) N fertilization. For both fertilization intensities, N balance surpluses and monetary returns from grain sales minus fertilizer expenditures were calculated in an economic assessment. Based on the field trials, the mineral N fertilizer application rates reduced by about 10% for rice and 20%-30% for wheat were recommended in 1999. Since 1999, the research focused on the trends in N fertilizer application rates and changes in grain and agricultural commodities prices.Summer rice N fertilizer use, in Wuxi City as of 2001, dropped by roughly 25%, while for winter wheat it decreased by 10%-20%, compared to the 1995-1998 period. This has been achieved not only by grain policy and price changes, but also by an increased environmental awareness from government officials. Nitrogen balance surpluses in Anzhen Town (of Wuxi City) have consequently diminished by 50%-75% in rice and by up to 40% in wheat, with reductions being achieved without concomitant decreases in physical grain yields or returns from sales minus fertilizer costs.
基金supported by Environmental Protection Department of Jiangsu Province and Suzhou Environmental Protection Bureau (Grant No ND2008-005)
文摘Based on a comprehensive analysis on various classifications of natural resource values,this paper summarizes an ecological services system of constructed wetland(CW) ecosystems for the accounting of ecological economic value.With the research,the wetland ecosystem services can be classified into six categories,that is waste treatment,food and material production,water supply,gas regulations,disturbance and water regulations,habitat and refuge provision.For decision making in terms of environmental economics for wetland construction,ecosystem services value for the wetland in Suzhou Taihu Lake National Tourist and Holiday Resort is accounted for 7,088,769 USD/yr through Environmental Economics Analysis.Ecosystem services value of waste treatment is 825,000 USD/yr,that of food and material production is 1,430 USD/yr,that of water supply is 4,752,000 USD/yr,that of gas regulation is 2,251USD/yr,that of disturbance and water regulations is 1,3721 USD/yr,and that of habitat and refuge provision value is 1,494,367 USD/yr.The ecosystem services values of a pilot constructed wetland in Suzhou are compared with those of other wetlands as a mean and of a typical human-interfered wetland in Wenzhou of China.Results show that in both finite and infinite time horizons considered,the wetland in Suzhou Taihu Lake National Tourist and Holiday Resort has the largest services value.This paper analyzes all the probability that may weaken the value of the Suzhou Taihu Wetland in order to provide some advices for the wetland protection.
