渠井用水比例对土壤脱盐与地下水化学特征的影响

发布时间：2018-04-06 23:23

本文选题：渠井用水比例　切入点：土壤含盐量　出处：《中国农业科学》2017年03期

【摘要】：【目的】通过研究华北典型井渠结合灌区不同用水模式对区域土壤盐分分布、根层土壤脱盐、地下水化学特征的影响,探讨华北井渠结合灌区适宜的渠井用水比例。【方法】2013—2015年在人民胜利渠灌区选择西三干渠控制范围为典型区域,监测控制范围内降水量、地表水灌溉量、地下水灌溉量、0—100 cm土层土壤含盐量、地下水矿化度,分析不同用水模式对根层土壤盐分洗脱、地下水化学特征的影响。【结果】2013—2015年一支渠、二支渠、三支渠渠井用水比例分别介于0.72—1.03、2.50—2.63、0.65—1.26之间;2013—2015年冬小麦苗期,不同用水模式下0—100 cm土层土壤盐分垂向分布均表现为上高、中低、下高,尤其是0—20 cm土层土壤盐分表聚明显;2013—2015年冬小麦苗期一支渠控制范围内0—20 cm根层土壤盐分均值大于0.32 mS·cm~(-1)面积分别占到控制范围的60.38%、25.99%、41.16%,二支渠控制范围内0—20 cm根层土壤盐分均值大于0.32 mS·cm~(-1)面积分别占到控制范围的59.61%、0.94%、8.81%,三支渠控制范围内0—20 cm根层土壤盐分均值大于0.32 m S·cm~(-1)面积分别占到控制范围的84.40%、41.87%、52.49%,表明渠井用水比例与支渠控制范围内表层土壤含盐量大于0.32mS·cm~(-1)的面积呈负相关;对比2013年同期,2014年典型区内0—20 cm土壤脱盐率介于15.61%—25.85%,2015年典型区内0—20 cm土壤脱盐率介于13.33%—23.15%;不同渠井用水比例典型区域地下水水化学特征均表现为:地下水中阳离子由枯水期钙钠型转化为平水期的钠钙型,平水期地下水水文化学相具有强烈的碱化趋势,特别是平水期二支渠地下水溶解性总固体增幅分别为一支渠、三支渠的1.23、3.48倍,表明较大渠井用水比例地表水灌溉驱动了根层土壤脱盐,增加了地下水中可溶性盐分浓度;对比2014年平水期,2015年同期一支渠、二支渠和三支渠控制范围地下水钠吸附比分别降低了23.58%、36.82%和55.47%,且区域地下水钠吸附比均低于18分级值。【结论】综合2013—2015年0—100 cm土层土壤脱盐率、地下水化学特征变化,在华北典型井渠结合灌区采用较大的渠井用水比例可以促进耕层土壤的脱盐、抑制土壤盐分表聚,同时短期内改善地下水环境。
[Abstract]:[objective] to study the effects of different water use patterns on soil salt distribution, desalination of root soil and chemical characteristics of groundwater in typical well and canal irrigation area in North China.This paper probes into the suitable proportion of water for canal and well in North China well combined irrigation area. [methods] the control range of West third main Canal in Rensheng Canal Irrigation area from 2013 to 2015 is selected as typical area, the precipitation and surface water irrigation amount are monitored and controlled.The effects of different water use patterns on the salt removal and groundwater chemical characteristics of the root soil were analyzed. [results] one canal and two canals were used in 2013-2015.The water consumption ratio of the three channels ranged from 0.72-1.03U 2.50-2.63N 0.65-1.26 to the seedling stage of winter wheat in 2013-2015. The vertical distribution of soil salt in 0-100 cm soil layer under different water use patterns was higher, lower and lower.There was a negative correlation between the water ratio and the surface soil salt content (> 0.32mS cm ~ (-1)) in the branch canal control area.Compared with the same period in 2013, the desalinization rate of 0-20 cm soil in the typical area in 2014 was 15.61-25.85, and the desalinization rate of 0-20 cm soil in the typical area in 2015 was 13.33-23.15.The chemical characteristics of groundwater in the typical region of different water use ratio of canal and well were as follows:The cations in groundwater changed from calcium to sodium in dry water to sodium and calcium in normal water.The hydrochemical phase of groundwater has a strong trend of alkalization, especially the total solid increase of the solubility of groundwater in the two-branch canal in the plain period is 1.23 ~ 3.48 times of that of the three canals, respectively.The results show that the surface water irrigation of large canal wells drives the desalination of the root soil and increases the soluble salt concentration in the groundwater.The sodium adsorption ratio of groundwater in the control range of the second branch canal and the third branch canal decreased by 23.58% and 55.47%, respectively, and the regional sodium adsorption ratio of groundwater was lower than 18 grade values. [conclusion] the desalination rate of soil in the soil layer of 0-100 cm from 2013 to 2015 and the change of the chemical characteristics of groundwater were synthesized.In the typical well and canal combined irrigation area in North China, a large proportion of water used in canal and well can promote the desalination of topsoil, restrain the accumulation of soil salt, and improve the groundwater environment in the short term.
【作者单位】：中国农业科学院农田灌溉研究所;中国农业科学院河南新乡农业水土环境野外科学观测试验站;中国农业科学院农业水资源高效安全利用重点开放实验室;
【基金】：国家公益性行业(农业)科研专项(201203077) 中国农业科学院科技创新工程项目(CAAS-ASTIP-FIRI-03)
【分类号】：S273;S153

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