Suchergebnisse

AbstractSalinization in a soil–water–plant system is an important environmental issue that has caused public concerns. In this study, field column experiments are conducted to study the transport of water and salt in soils affected by hydrologic circle and plant growth. A soil water and salt transport model (SWSTM) is developed and calibrated for predicting the behaviour of water and salt in a soil–water–plant system. The model takes into account water and solute uptake by crop roots and migration to groundwater. The experiment results demonstrate that the rise of the groundwater table enhances the movement of water and results in the accumulation of salt at a layer of 45 cm depth. With the decline of the groundwater table, the amount of accumulated salt increases correspondingly. The simulation results demonstrate that the SWSTM adequately predicts the water and salt transport in a soil–crop–plant system under different groundwater tables. The use of SWSTM will help to reveal the mechanism of water and salt transport in a soil–water–plant system. The SWSTM can also serve as a useful tool in evaluating the impact of agricultural activities and formulating efficient water management strategies in China.

AbstractThe frequent outbreaks of water eutrophication in Gehu Lake are regarded as one of the most troublesome environmental issues in Southeast China. Based on the water's potential capacity to accept pollutant loads, a catchment‐scale environmental management system was established to ensure inflows of clean water into Taihu Lake. Considering the complexity of the hydrological regimes operating within the river‐network plain, the capacities of the water environment for loads of COD and nutrients were estimated using the Water Quality Analysis Simulation Program, Version 7.3 (WASP 7.3) model. The calibration and the verification of this model were based on water quality measurements during the period 2009–2010. The variables of water quality that were examined are COD, NH4‐N, TN and TP. The simulated distributions of the COD, NH4‐N, TN and TP in the water column agree with the observations, but it indicates that more measurements are needed to verify the predictability of the simulations. The simulation results show that the average relative error is small, and the change trend of each indicator is consistent. The results have shown that the WASP model can be used to evaluate the future water quality changes in case that the pollution continues with the same rate. The work presented in this paper is expected to be a theoretical basis in exploring the degradation mechanism for self‐purification capacity of water bodies and in designing and constructing of Gehu Lake ecosystem restoration goals.