Recent trends of nitrogen flow of typical agro-ecosystems in China--major problems and potential solutions.

Background: To diagnose problems that threaten regional sustainability and to devise appropriate treatment measures in China's agro-ecosystems, a study was carried out to quantify the nitrogen (N) flow in China's typical agro-ecosystems and develop potential solutions to the increasing environmental N load.

Results: The analysis showed that owing to human activity in the agro-ecosystems of Changjiang River Basin the mean total input of anthropogenic reactive N (i.e.

Effect of reforestation on nitrogen and phosphorus dynamics in the catchment ecosystems of subtropical China: the example of the Hanjiang River basin.

Background: To enable effective management and decision making for the sustainable use of water resources, we successfully integrated factors such as dams, land use and soil properties as well as management factors in the Hanjiang River basin, a subtropical catchment of China, into the SWAT model to simulate water cycles as well as the distribution, movement, and transformations of nutrients.

Results: The accuracy of the model was validated by monitoring data over the Hanjiang River. The validated model was then used to evaluate the effects of the Reforestation of Cultivated Land (RFCL) initiative.