?植物修復模式對離子型稀土堆浸尾礦土壤入滲特性的影響

摘 要：為了明確植物修復模式對離子型稀土堆浸尾礦土壤入滲特征的影響，以未治理的堆浸尾礦為對照（CK），設置堆浸尾礦種植皇竹草（T1）和堆浸尾礦種植臍橙（T2）2種植物修復模式，利用圓盤入滲儀觀測各處理的土壤入滲特性，并分析其影響因素。結果表明：（1）不同處理下土壤有機質含量、容重、土壤含水量、砂粒和黏粒含量差異顯著（P＜0.05），2種植物修復堆浸尾礦的土壤有機質含量、黏粒含量顯著高于未治理堆浸尾礦（P＜0.05），而砂粒含量顯著低于未治理堆浸尾礦（P＜0.05）；（2）與未治理堆浸尾礦相比，植物修復模式使土壤初始入滲率、穩定入滲率和累積入滲量下降82.0%～93.5%，穩定入滲時間約減少15 min ；（3）初始入滲速率、穩定入滲速率與砂粒含量呈極顯著指數正相關關系（P＜0.01），穩定入滲時間與有機質含量和黏粒含量呈極顯著冪函數負相關（P＜0.01）。綜上所述，贛南離子型稀土堆浸尾礦保水能力極差，采用植物修復模式可有效恢復土壤涵養水分的功能。

關鍵詞：植物修復；離子型稀土；堆浸尾礦；治理模式；土壤有機質；土壤質地

中圖分類號：S152.7 文獻標識碼：A 文章編號：1006-060X（2023）04-0055-06

Abstract： In order to clarify the influence of phytoremediation model on soil infiltration characteristics of ionic rare earth heap leaching tailings， this study， taking the untreated ionic rare earth heap leaching tailings as CK， set two phytoremediation models of planting Pennisetum hydridum （T1） or navel orange （T2） on the heap leaching tailings. The soil infiltration characteristics of each treatment were observed with a disk infiltration meter， and the influencing factors were analyzed. The results showed that： （1） The soil organic matter content， bulk density， soil water content， and sand and clay contents exhibited significant differences among treatments （P＜0.05）. The two phytoremediation models were significantly higher than CK in soil organic matter and clay contents （P＜0.05）， but significantly lower than CK in the sand content （P＜0.05）. （2） Compared with CK， the phytoremediation models reduced the soil initial infiltration rate， stable infiltration rate and cumulative infiltration amount by 82.0%–93.5%， and shortened the stable infiltration time by about 15 minutes. （3） The initial infiltration rate and stable infiltration rate respectively showed a very significantly exponential function positive relationship with sand content （P＜0.01）; the stable infiltration time had a very significantly power function negative relationship respectivly with organic matter content and clay content （P＜0.01）. To sum up， the water holding capacity of ionic rare earth heap leaching tailings in southern Jiangxi is extremely poor， and the use of phytoremediation model can effectively restore the function of soil water conservation.

Key words：phytoremediation; ionic rare earth; heap leaching tailing; management model; soil organic matter; soil texture

離子型稀土是重型稀土的主要來源[1]，全球重型稀土儲量最豐富的區域位于我國江西省贛南地區[2-3]。離子型稀土的開采有池浸、堆浸和原位浸礦工藝[4-5]，堆浸尾礦在贛南地區占有很大比例（約41%），是目前主要的稀土尾礦存在方式[6]。堆浸工藝需要剝離表層土壤后將不同層次土壤移位混合，這會造成花崗巖發育的母質層外露。花崗巖發育的母質砂粒含量高、土壤結構差、水分涵養能力低，進而導致土壤失去維持植物正常生長所需的水分條件。……