摘要
【目的】稀土开采带来了严重的生态环境问题,如水土流失、养分枯竭、土壤结构破坏、植被恢复困难等。土壤改良是当前稀土尾矿生态修复的研究热点。探究凹凸棒土(A)、生物炭(B)、聚丙烯酰胺(C)和腐植酸(D)复配而成的土壤改良剂对稀土尾矿土壤理化性质及酶活性的改良效益,以期为稀土尾矿土壤改良及生态修复提供理论指导。【方法】通过盆栽法,开展四因素四水平正交试验,以土壤理化性质及酶活性作为评价指标,利用综合评分法对土壤改良配方进行系统优化,并根据优化后的改良方案,进行植物生长试验,以望江南(Cassia occidentalis)的出苗率、株高、主根长以及地径作为评价指标,验证复合土壤改良剂的添加对植物生长的促进效果。【结果】复合土壤改良剂的添加显著改善了稀土尾矿土壤的理化性质。与未经改良的稀土尾矿土壤相比,添加复合土壤改良剂降低了土壤容重,并显著提高了土壤pH、硝态氮、有效磷、速效钾、全钾和有机质的含量,其增幅分别为10.05%~54.03%、36.40%~65.60%、488.53%~1415.31%、40.50%~164.75%、25.44%~38.48%、78.64%~396.21%。在酶活性方面,脲酶活性提高了45.65%~122.78%,但酸性磷酸酶、β-葡萄糖苷酶和蔗糖酶活性有所下降,而蛋白酶活性无显著变化。通过排队评分法得到稀土尾矿土壤改良最优配方为A2B1C4D4(凹凸棒土10 g/kg:生物炭0 g/kg:聚丙烯酰胺3 g/kg:腐植酸3 g/kg)。进一步的植物生长试验表明,望江南在该配方改良的土壤中生长状况优良,与未经改良的稀土尾矿土壤相比,望江南的出苗率、株高、主根长及地径分别显著提高了149.97%、464.88%、364.16%、241.92%。【结论】凹凸棒土、生物炭、聚丙烯酰胺和腐植酸可作为稀土尾矿土壤改良的有效材料。本研究可为稀土尾矿土壤的修复及植被恢复提供理论支撑。
[Objective]Rare earth mining has resulted in severe ecological and environmental problems,such as soil erosion,nutrient depletion,degradation of soil structure,and difficulties in vegetation restoration.Soil remediation is a research hotpot within the context of ecological restoration for rare earth tailings.This study investigated the efficacy of composite soil amendments comprising attapulgite(A),biochar(B),polyacrylamide(C),and humic acid(D)on enhancing the physicochemical properties as well as enzyme activity in rare earth tailings soil,thus providing theoretical guidance for the remediation and ecological rehabilitation of rare earth tailing.[Method]Through the pot method,a four-factor and four-level orthogonal experiment was conducted.With the soil physicochemical properties and enzyme activities as the evaluation indexes,the soil improvement formula was systematically optimized by the comprehensive scoring method.According to the optimized improvement scheme,the plant growth experiment was conducted,taking the emergence rate,plant height,main root length and ground diameter of Cassia occidentalis as the evaluation indexes to verify the promoting effect of the addition of the composite soil amendment on plant growth.[Result]The addition of composite soil conditioner significantly improved the physical and chemical properties of rare earth tailings soil.Compared with the untreated rare earth tailings soil,the addition of the composite soil improver reduced soil bulk density and significantly increased the contents of soil pH,nitrate nitrogen,available phosphorus,available potassium,total potassium and organic matter,with increases ranging from 10.05%-54.03%,36.40%-65.60%,488.53%-1415.31%,40.50%-164.75%,25.44%-38.48% and 78.64%-396.21%,respectively.In terms of enzyme activity,urease activity increased by 45.65%-122.78%,but acid phosphatase,β-glucosidase and sucrase activity decreased,while protease activity showed no significant change.Through the comprehensive queuing scoring method,the optimal formula for soil improvement of rare earth tailings was A2B1C4D4(attapulgite 10 g/kg,biochar 0 g/kg,polyacrylamide 3 g/kg,humic acid 3 g/kg).Further plant validation experiments showed that Cassia occidentalis grew well in the soil improved by this formula.Compared with the unimproved rare earth tailings soil,the seedling emergence rate,plant height,main root length and ground diameter of Cassia occidentalis were significantly increased by 149.97%,464.88%,364.16% and 241.92%.[Conclusion]Attapulgite,biochar,polyacrylamide and humic acid can be used as effective materials for soil improvement of rare earth tailings.This study can provide a theoretical support for soil remediation and vegetation restoration of rare earth tailings.
作者
王艳
夏志强
吴璇
倪晓华
汪薇
郭圣茂
WANG Yan;XIA Zhiqiang;WU Xuan;NI Xiaohua;WANG Wei;GUO Shengmao(College of Forestry,Jiangxi Key Laboratory of Subtropical Forest Resources Cultivation,Jiangxi Agricultural University,Nanchang 330045,China)
出处
《江西农业大学学报》
北大核心
2025年第1期255-266,共12页
Acta Agriculturae Universitatis Jiangxiensis
基金
国家自然科学基金项目(31560204)。
关键词
稀土尾矿
土壤改良剂
土壤理化性质
酶活性
rare earth tailings
soil amendment
soil physicochemical properties
enzyme activity
