节水灌溉对关中地区土壤环境及地下水位的影响研究

发布时间：2019-02-24 19:28

【摘要】：本文通过分析关中地区泾惠渠、桃曲坡、东雷抽黄一期、二期四个典型灌区的渠系衬砌,长畦改短畦、宽畦改窄畦等节水措施对土壤肥力、土壤结构、地下水等的影响,获取节水灌溉对关中典型作物农田水土环境影响及其机理,旨为关中干旱半干旱区节水灌溉农业可持续发展提供科学依据,最终实现节水灌溉与生态环境建设和谐发展。主要得出以下结论:(1)关中地区典型灌区渠道衬砌材料,衬砌完善程度以及渠道的维护都制约着渠道沿途土壤有机质含量,且呈现衬砌材料密实性越好,完善度越高,渠道维护工作越好,有机质含量相对较低的趋势;反之则具有较高有机质含量。其中,泾惠灌区衬砌渠道两侧土壤有机质含量介于18.96～162.92 mg/kg,均值为86.07 mg/kg,变异系数为0.367;渠道衬砌率较高的桃曲坡灌区渠道两侧土壤有机质含量介于5.21～17.57g/kg之间,均值为10.01g/kg,变异系数为0.396;东雷抽黄一期灌区样本有机质含量介于3.25～21.24g/kg之间,平均含量为8.5g/kg;变异系数为0.336;东雷二期灌区渠道沿途两侧有机质含量介于4.82～20.67g/kg,平均含量为9.53g/kg,变异系数为0.32;且四个灌区有机质含量均属于中等变异程度,具有中等的空间相关性。对比分析四个灌区沿途渠道土壤有机质含量以及不同颗粒含量分布发现,黏粒含量、粉粒含量空间分布趋势与有机质分布几乎相一致,两者具有较高相关性。(2)通过田间渠道渗漏试验,结合近几年泾惠灌区地下水埋深变化,同时基于Hydrus-2D模型,对不同材料衬砌渠道的渗漏量进行了积水后的第30天、第60天、第120天、第180天的变化预测。结果发现,由于渠道防渗材料的升级,渠道防渗效果随之增强,相应的渠道渗漏深度变浅,渗漏量减少。渠道渗漏对于泾惠灌区地下水的补给也逐渐减少,甚至完全中断。(3)通过收集以往学者的畦田灌溉实测资料并结合WinSRFR模型,模拟预测畦田改造对土壤环境的影响。结果发现:当畦田长度60m～160m时,畦田宽度由4m递增到9m,单宽流量相应变小,水流推进运动所需要的时间变长,水流消退过程所需要的时间变短;在距离畦首相同位置处,随着畦宽的增加,土壤水分入渗先有减小趋势,后有明显增大趋势。当畦宽M=4～9m时,改变其畦田长度60m～160m,不影响其水流推进过程;畦宽M=4m时,单宽流量较大,在畦尾处会产生积水,水流消退速率变慢,消退时间增幅明显;当畦宽M=6, 9m时,单宽流量较小,在畦尾处会产生渗漏,畦尾水可能先于其他处消退。在距离畦首相同位置处,畦田长度越长,土壤水分入渗较大,畦长对土壤水分入渗影响明显。
[Abstract]:This paper analyzes the effects of water saving measures on soil fertility, soil structure, groundwater and so on in four typical irrigation areas in Guanzhong area, such as Jinghui canal, peach slope, Donglei Yellow River pumping first stage, the second stage of four typical irrigation areas, such as lining, long furrow to short furrow, wide furrow to narrow furrow, etc. The effects of water-saving irrigation on the soil and water environment of typical crops in Guanzhong and its mechanism are obtained to provide a scientific basis for the sustainable development of water-saving irrigation agriculture in arid and semi-arid areas of Guanzhong, and to realize the harmonious development of water-saving irrigation and ecological environment construction. The main conclusions are as follows: (1) the lining materials, the degree of lining perfection and the canal maintenance in Guanzhong region restrict the content of soil organic matter along the channel, and the better the compactness of the lining material, the higher the perfection. The better the work of canal maintenance, the lower the content of organic matter. On the contrary, the content of organic matter is higher. Among them, the soil organic matter content on both sides of the lining canal in Jinghui Irrigation area was between 18.96 and 162.92 mg/kg, the mean value was 86.07 mg/kg, and the coefficient of variation was 0.367; The soil organic matter content on both sides of the canal in Taoqu slope irrigation area with high lining ratio was between 5.21~17.57g/kg, the mean value was 10.01 g / kg, and the coefficient of variation was 0.396; The content of organic matter in the first stage irrigation area of Donglei Yellow River was between 3.25~21.24g/kg, the average content was 8.5 g / kg, the coefficient of variation was 0.336; The content of organic matter along the canal was between 4.82 and 20.67 g / kg, the average content was 9.53 g / kg, and the coefficient of variation was 0.32; The content of organic matter in the four irrigated areas was of moderate variation and had moderate spatial correlation. By comparing and analyzing the soil organic matter content and different particle content distribution along the canal in four irrigation areas, it was found that the spatial distribution trend of clay and silt content was almost the same as that of organic matter distribution. (2) through field channel leakage test, combined with groundwater depth variation in Jinghui irrigation area in recent years, and based on Hydrus-2D model, the leakage of different materials lining canal was carried out 30 days after water accumulation. 60 th day, 120 th day, 180 th day change forecast. The results show that because of the upgrading of the channel impervious material, the channel seepage control effect is enhanced, the corresponding channel leakage depth is shallower, and the leakage amount is reduced. The groundwater recharge in Jinghui Irrigation area was gradually reduced or even completely interrupted by canal leakage. (3) the effects of border irrigation on soil environment were simulated and predicted by collecting the measured data of border irrigation from previous scholars and combining with WinSRFR model. The results show that when the border length is 60m~160m, the width of border field increases from 4 m to 9 m, the single width flow becomes smaller, the time required for water flow to move forward becomes longer, and the time required for flow regression process becomes shorter. At the same position from the top of the furrow, with the increase of the width of the furrow, the infiltration of soil moisture decreased first, then increased obviously. When the width of the furrow is 4 ~ 9 m, the length of the border is 60m / 160m, which does not affect the course of water flow, and when the width of the furrow is 4m, the single width discharge is larger, the water will be accumulated at the end of the furrow, the rate of flow fading will become slow, and the time of receding will increase obviously. When the width of the furrow is 6m and 9m, the flow rate of single width is smaller, the leakage will occur at the end of the furrow, and the tail water of the furrow may dissipate before the rest of the bed. The longer the border field length is, the larger the infiltration of soil water is, and the longer the border length is, the more the border length affects the infiltration of soil water.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S274

【参考文献】