关键词: 氮胁迫, 养分吸收与利用, 生物量分配, 水曲柳

Abstract: Based on the framework of the structure and function of socialeconomicnatural complex ecosystem, and with the focus on the rural sanitation system of China, the current status of China rural sanitation was analyzed. Six districts for developing ecological sanitation (ecosan) in this country were divided, with the consideration of geographic distribution and socialeconomic status, and four categories of rural sanitation system of the six districts and their population distribution were studied. The districts with the highest potential of developing ecosan were those without basic sanitation and lacking of investment capacity, which carried a population of 468.2 million, and 67.8% of the population was mainly in the middlewest and southwest of China. If the ecosan would be developed there, new industries could be promoted and 50-100 thousands of employing opportunities could be created, incidence rate of diseases could be reduced, 560 thousand cubic meters of methane could be recycled, investment of sanitary toilet could be reduced to an acceptable price, i.e., 600-750 RMB yuan per house, ecological agriculture could be developed, and pollutants discharge could be reduced while ecological security could be guaranteed. The strategy of developing ecosan in each district and the system bottlenecks were also discussed in this paper.

Key words: Nitrogen stress, Nutrient uptake, Biomass distribution, Fraxinus mandshurica