保水剂对干湿循环的响应及对稀土尾砂土壤水分状况的影响  

Response of Super-absorbent Polymers to Dry-Wet Cycle and Effect on Soil Moisture in Rare Earth Tailing Area

作　　者：贺燕子 田芷源 马瑞 朱绪超 HE Yanzi;TIAN Zhiyuan;MA Rui;ZHU Xuchao(State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院南京土壤研究所/土壤与农业可持续发展国家重点实验室,江苏南京210008 [2]中国科学院大学,北京100049

出　　处：《江西农业大学学报》2023年第1期210-219,共10页Acta Agriculturae Universitatis Jiangxiensis

基　　金：国家重点研发计划项目(2019YFC1805104、2021FYD1500801)。

摘　　要：【目的】南方地区离子型稀土尾矿区的生态环境脆弱,强烈的干湿交替条件加剧了土壤水分亏缺。保水剂由于吸水持水能力强,研究其在稀土尾矿区的应用对于提升土壤水分条件、促进尾矿区生态恢复具有重要的实践意义。【方法】通过模拟土壤吸水和蒸发过程,分析了6次干湿循环条件下保水剂粒径(1.0~2.0 mm、0.45~1.0 mm、<0.18 mm)及浓度(0.2%、0.4%、0.6%)对尾砂土保水和持水能力的影响,为开展保水剂田间应用提供理论依据。【结果】(1)稀土尾砂区土壤水分条件差,其土壤饱和含水量(SWC)显著低于未采矿区自然土(36.21%<39.85%),自然条件下土壤水分蒸发快、完全干旱时间较短;添加保水剂能显著改善尾砂土壤水分状况,尾砂土SWC提升了0.12~0.91倍,通过抵御土壤水分蒸发,土壤完全干旱时间延长了0.67倍,土壤保水持水能力得到提升。(2)保水剂应用效果主要受到土壤干湿循环因素的影响,经历6次干湿循环后添加保水剂的尾砂土SWC从54.87%降至39.33%,土壤完全干旱时间缩短,土壤中的保水剂吸水倍数(SC)从47.19 g/g降至18.01 g/g;削弱效应主要发生在初次循环后,相比循环1次,循环2次后尾砂土SWC和保水剂SC分别降低19.43%和9.39 g/g,尽管如此经历多次循环后应用保水剂的尾砂土水分条件仍优于未采矿区自然土壤(39.33%>34.25%)。(3)保水剂施用方式中,浓度是影响保水剂应用效果的主要因素,粒径则主要影响保水剂吸水性能,两者交互作用显著,浓度和粒径越大,土壤保水持水能力提升效果越好,相比浓度0.2%、粒径<0.18 mm的保水剂,添加浓度0.6%、粒径1.0~2.0 mm的保水剂后,尾砂土SWC和保水剂SC分别提升0.41倍和0.62倍,土壤完全干旱时间延长0.67倍;土壤干湿循环通过破坏保水剂网状结构削弱了其在土壤中的浓度和粒径效应,高浓度和大粒径保水剂更耐久,6次循环后添加0.6%、1.0~2.0 mm的保水剂的尾砂土SWC�[Objective]The ecological environment of the ionic rare earth tailing mine in South China is fragile,and the strong alternation of the dry-wet cycle intensifies the soil water deficit. As super-absorbent polymers(SAPs)have a strong ability to absorb and hold water,it is of great practical significance to study their application for improving soil moisture conditions and promoting ecological restoration in the rare earth tailing area.[Method]By simulating soil water absorption and evaporation process,the effects of particle size(1.0-2.0mm,0.45-1 mm,and <0.18 mm)and concentration(0.2%,0.4%,and 0.6%)of SAPs on water retention and water-holding capacity of tailing soil were analyzed under six dry-wet cycles,which provides a theoretical basis for its field application.[Result](1)The soil water condition in the rare earth tailing area was poor,and the soil saturated water content(SWC)was significantly lower than that of the natural soil in an unmined area(36.21%<39.85%).Under the natural condition,the soil water evaporation was faster and the complete drought time of tailing soil was shorter.The SAPs could significantly improve the tailing soil moisture status.It increased SWC of the tailing soil by 0.12-0.91 times,prolonged the complete drought time of tailing soil by 0.67 times,and improved the soil water retention and water holding capacity by resisting soil water evaporation.(2)The application effect of SAPs in tailing soil was mainly affected by the soil dry-wet cycle.After six dry-wet cycles,the SWC of tailing soil with SAPs decreased from 54.87% to 39.33%,the complete drought time of tailing soil was shortened,and the swelling capacity(SC)of SAPs in tailing soil decreased from 47.19 g/g to 18.01 g/g.The weakening effect of the soil dry-wet cycle on SAPs mainly occurred after the first cycle.Compared with the first soil dry-wet cycle,SWC and SC in the second soil dry-wet cycle decreased by 19.43% and 9.39 g/g,respectively.However,the water condition of tailing soil with SAPs was still better than that of natural

关 键 词：保水剂 干湿循环 离子型稀土尾矿 土壤水分条件 土壤蒸发 

分 类 号：S152.7[农业科学—土壤学]