黄石铁尾矿废弃地刺槐人工林土壤肥力研究

用常规方法测定了覆盖混合基质的黄石铁尾矿废弃地的刺槐Robinia pseudoacacia人工林土壤的pH以及有机质、全氮、全磷、全钾、碱解氮、速效磷和速效钾含量,用稀释平板法测定土壤固氮菌和解磷菌数量,分别用比色法、磷酸苯二钠比色法和高锰酸钾滴定法测定脲酶、磷酸酶及过氧化氢酶酶活性.结果表明,刺槐人工林下土壤pH比未种植植物的铁尾矿废弃地低4.7%,土壤的有机质、全氮、全磷质量分数分别为101.5、2.8和1.5 g.kg-1,碱解氮、速效磷和速效钾质量分数分别为、130.7、16.2和201.8 mg.kg-1,均极显著高于对照,而土壤的全钾含量比对照低13.7%.刺槐人工林土壤的自生固氮菌数量与解磷菌数量分别为75.0×105和85.7×105 cfu.g-1,土壤脲酶、磷酸酶和过氧化氢酶活性分别为2.7 g.kg-1.d-1、317.6 mg.kg-1.h-1和4.6 mL.g-1.h-1,均极显著高于对照.可见,覆盖混合基质能够提高养分含量,促进刺槐的定居,而刺槐的生长进一步改善了土壤性质,促进了铁尾矿废弃地的生态恢复.

Study on Soil Fertility of a Robinia pseudoacacia Plantation in an Abandoned Iron Tailing Area in Huangshi

Soil characteristics of a Robinia pseudoacacia plantation was investigated in an abandoned iron tailing area in Huangshi City to provide guidance for soil remediation of abandoned mine lands. Soil pH, organic matter, total N, total P, total K, alkali-hydrolyzable N, available P, and available K were determined by routine method, the number of diazotrophs and the phosphate-solubilizing bacteria number were determined by dilution plate method, and activities of soil urease, phosphatase and catalase were determined by colorimetry, disodium phenyl phosphate colorimetric method and titration with potassium permanganate, respectively. The contents of soil organic matter, total N, total P were 101.5, 2.8, 1.5 g·kg^-1, and alkali-hydrolyzable N, available P, and available K were 130.7, 16.2, 201.8 mg·kg^-1 respectively in the soil of the R. pseudoacacia plantation, which were significantly greater than those of the abandoned iron tailing without vegetation, while total K was lower by 13.7% compared with the control. The number of diazotrophs and phosphate-solubilizing bacteria were 75.0×10⁵ and 85.7×10⁵ cfu·g^-1 respectively, and activities of urease, phosphatase and catalase were 2.7 g·kg^-1·d^-1, 317.6 mg·kg^-1·h^-1 and 4.6 mL·g^-1·h^-1, respectively, which were significantly greater than those of the controls. Soil structure of the abandoned iron tailing was improved and nutrient content was increased because of covering mixed substrate, which facilitated the colonization of R. pseudoacacia, and the growth of R. pseudoacacia further improved soil properties and facilitated the ecological restoration of abandoned iron tailing.