保水剂用量对排土场土壤持水性的影响  

Effects of water-retaining agent content on the water-holding characteristics of soil in waste dump

作　　者：胡杨 张俊娇 史常青[1] 赵廷宁[1] 刘小勇 吴川 刘秉儒 HU Yang;ZHANG Junjiao;SHI Changqing;ZHAO Tingning;LIU Xiaoyong;WU Chuan;LIU Bingru(School of Soil and Water Conservation,Beijing Forestry University,100083,Beijing,China;Key Laboratory of Ecosystem Modeling and Application of National Civil Commission,College of Biological Science and Engineering,North Minzu University,750021,Yinchuan,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]北方民族大学生物科学与工程学院,生态系统建模及应用国家民委重点实验室,银川750021

出　　处：《中国水土保持科学》2022年第2期115-123,共9页Science of Soil and Water Conservation

基　　金：宁夏回族自治区重点研发计划“贺兰山保护区采煤迹地生态修复技术与模式研究”(2018BFG02002)。

摘　　要：露天煤矿排土场土壤(渣土)孔隙环境及保水性能差,不适于结合植被进行生态修复。为改良矿区渣土水分,选取宁夏汝箕沟大峰矿的渣土,利用土壤高速离心机模拟含保水剂渣土的脱湿过程,结合Van Genuchten模型分析渣土的土壤水分特征曲线及参数、水分有效性和孔径分布,定量评估保水剂对渣土持水特性的影响,选出最适宜该矿区的保水剂用量。结果表明:1)保水剂对渣土的持水性在低吸力段依靠其毛管孔隙状况,且随用量的增加,渣土毛管孔隙持水能力随之增加;2)保水剂用量的增加可显著提高渣土的全有效水含量、速效水含量、中孔隙比例、微孔隙比例、超微孔隙比例,但保水剂用量≥1.0%不利于提高渣土的水分有效性及形成适宜植物生长的孔隙环境;3)保水剂改善渣土水分有效性、满足适宜植物生长渣土孔隙分布条件的最佳用量为0.5%。[Background]The waste dump soil(muck)produced by the open-pit coal mines is an artificial loose accumulation with poor water-holding characteristics and uneven pore distribution,which is not conducive to vegetation growth.This phenomenon is more serious in arid and semi-arid areas and has become an important factor restricting the use of vegetation for ecological restoration in mining areas.Based on this,different water-retaining agent content were applied to the muck of Ningxia open-pit coal mine to improve the water-holding characteristics,water availability and pore environment of the muck,and the optimal content was selected.[Methods]We set up 3 sampling points on the upslope,mid-slope,and downslope at the dumping site of Dafeng Mine in Rujigou,Shizuishan city,Ningxia.We then collected and mixed 0-20 cm muck,then passed them through a 2 mm soil sieve and determined its density and particle composition.The soil high-speed centrifuge was used to simulate the dehumidification process of the muck containing water-retaining agent,and Van Genuchten model was used to analyze the effect of the soil water characteristic curve,fitting parameters,water availability and pore distribution of the muck with different water-retaining agent content.[Results]1)Muck’s water content decreased sharply with the increase of soil water suction at low suction stage,and it was positively correlated with water-retaining agent content,but the downward trend slowed down at low suction stage and had no significant change at high suction stage.2)Saturated water content(θ_(s))increased with the increase of water-retaining agent content.The inverse of air-entry value(α)reduced siginificantly by the use of water-retaining agent,but it increased first and then decreased,and the peak appeared at 1.0%treatment.Residual water content(θ_(r))had no significant difference,and the value of shape parameter(n)had no obvious change rule.3)Water-retaining agent increased the total available water and easily available water content of muck by 1.12-3.

关 键 词：排土场 保水剂 土壤水分特征曲线 水分有效性 土壤孔隙分布 

分 类 号：S152.7[农业科学—土壤学]