基于SWAP模型的民勤绿洲地下水灌溉研究

The project analysis the effects of natural and human factors on ground water resources based on the discussion of water resources, ground water level and concentration changes, and clarify the reasons for deteriorating of ground water in the Minqin Oasis. Saline water is not beneficial to irrigated agriculture but it may still be the major irrigation water source in extensive arid regions, for example, due to the lack of freshwater, highly saline ground water was the main irrigation source in the last few decades in the Minqin oasis, northwest China. For sustaining the existing croplands and guaranteeing subsistence, local farmers have to exploit the ground water with high salinity to irrigate croplands, which leads to salt accumulation in the soil under strong evaporation. Soil salinization results in the dry out of vegetation, desertification, land encroachment and environmental degradation. The negative impact of saline irrigation water can be mitigated by implementing appropriate management of saline water, soil and plant.In this study, through the SWAP model which will be calibrated with experimental data to simulate the movements of water and salt in the soil, plant growth and productivities under different irrigation water and plant conditions. According to the simulation of micro data results to determine the different reasonable regional ground water use methods in the different kinds of irrigation areas in Minqin oasis, and determine the utilization of ground water in the whole study region. This study can provide theoretic support for reasonable utilization of local limited ground water resources and serve for sustainable development of agriculture and ecological environmental construct. Implementation of the project is not only has an important practical significance for promoting the rational use of ground water resources, ecological civilization construction and sustainable development of agriculture in the Minqin oasis but also has important scientific significance for water resources, vegetation protection and ecological civilization construction in arid areas.

本项目基于野外试验和模型模拟定量分析结果确定民勤绿洲地下水灌溉利用的合理方法。通过野外大田跟踪试验实测数据对SWAP模型进行率定，利用率定后的模型对民勤绿洲不同灌区地下水和不同典型作物条件下的土壤水盐运移、作物生长及产量进行模拟，明确民勤绿洲不同灌区地下水灌溉对作物和土壤环境的影响，确定各灌区典型作物条件下单位土地面积需水量。基于微观的模型模拟结果来确定民勤绿洲不同灌区地下水灌溉的合理方法，进而制定整个研究区地下水灌溉利用方案，以期为民勤宝贵的地下水资源的有效使用提供理论支撑，为生态环境保护和农业可持续发展服务。本项目的实施不仅对促进民勤绿洲地下水资源的合理利用、当地生态环境保护和农业可持续发展具有重要的现实意义，而且对于干旱区的水资源使用、植被保护和生态文明建设具有重要的科学意义。

水是制约干旱区经济和生态环境平衡发展的关键因素。由于气候变化、中上游用水量的增加和不合理的水资源利用方式，导致位于石羊河下游的民勤绿洲不得不开采地下咸水以满足生产生活需求。地下水的过度开采及不合理的利用方式导致土地盐渍化和水资源浪费，影响社会经济发展和生态环境建设。.本项目基于野外试验和模型模拟定量分析结果确定民勤绿洲地下水灌溉利用的合理方法。通过野外大田跟踪试验实测数据对SWAP模型进行率定，利用率定后的模型对民勤绿洲不同灌区地下水和不同典型作物条件下的土壤水盐运移、作物生长及产量进行模拟，明确民勤绿洲不同灌区地下水灌溉对作物和土壤环境的影响，基于微观的模型模拟结果来确定民勤绿洲不同灌区地下水灌溉的合理方法，进而制定整个研究区地下水灌溉利用方案。.研究结果表明，自民勤西南向东北地下水水位逐渐下降，矿化度逐渐升高，最高可达12 g L-1；无论淡水还是咸水处理，SWAP模型模拟含水量和实测含水量均有一定差异，但总体趋势上具有比较好的一致性，整个土壤剖面上( 0-100 cm)淡水和咸水处理的均方根误差分别为0.060和0.045， 校正效果较好。该模型可以用于指导当地农业管理。民勤绿洲农业灌溉用水不足的形势下，通过膜下滴灌的方式，在生殖生长期利用淡水灌溉在营养生长期利用咸水进行灌溉，既能减少咸水灌溉对土壤和作物的损害，又能保障作物产量；在地下水矿化度较高的民勤绿洲东北部，调整种植结构，选择耐盐碱需水量少的农作物进行大面积种植；在绿洲荒漠过渡带控制种植作物品系，进行苜蓿种植家畜饲养，控制灌溉水量，提高植被覆盖度，保护脆弱生态环境。.本项目的实施不仅对促进民勤绿洲地下水资源的合理利用、当地生态环境保护和农业可持续发展具有重要的现实意义，而且对于干旱区的水资源使用、植被保护和生态文明建设具有重要的科学意义。