干旱区微咸水灌溉的水-土环境效应预测研究

本文运用MODFLOW及SWAP模型对微咸水灌溉的水-土环境效应进行了预测.模型参数用2004年的观测资料进行率定,并用2002年的资料对模型的可靠性进行了检验.结果显示,淋洗灌溉定额条件下,不同作物的土壤盐分积累及作物相对减产率分别比正常灌溉定额条件下有所降低;微成水灌溉后土壤盐分的积累随着时间的推移呈递减趋势,大约在10年后盐分达到进出平衡状态,平衡时土壤的含盐量(0.126%)仍属于轻度盐渍土;抽取地下微咸水灌溉后,淋洗灌溉定额条件地下水位的下降幅度及含水层盐分的增加量都比正常灌溉定额条件下有所降低.采用微咸水灌溉,淋洗灌溉比正常灌溉对环境有利.

Prediction of water soil environment effect under brackish water irrigation in arid area

The effect of soil water environment under blackish water irrigation in arid area is predicted by using the visual MODFLOW model combining with SWAP model. The parameters of the models are calibrated by experimental data obtained in 2004 and the validity of the model is verified by using the observation data obtained in 2002. It is found that the accumulative salinity in soil and relative yield reduction for different crop under the condition of leaching treatment are decreased. The accumulative salinity tends to decrease and reaches an equilibrium state after 10 years with soil salinity concentration 0.126% which is a kind of slightly salted soil. The lowering of ground water table and increase of salinity in aquifer under the condition of leaching treatment are lower than that under the condition of normal treatment. It may conclude that the environment effect of leaching treatment irrigation mode is better than that of normal treatment irrigation mode.