构树对菱镁矿区破损土地的生态适应性

目的]研究菱镁矿粉尘对土壤理化性质的影响以及构树对镁粉尘污染土壤的耐受性.方法]采用盆栽试验,室内模拟氧化镁粉尘沉降、人工掺和废矿堆.结果]当镁粉尘施加量小于10％时,促进构树生长,当土壤镁含量为4.17 g/kg时,构树单株生物量达3.46g,明显大于洁净土壤的生物量（2.81 g）;构树对生长土质的要求低,土壤中矿石含量25％时,生物量最大为6.12g,明显比洁净土壤生物量高出3.31 g;施加镁粉尘明显改变了构树生长土壤的理化性质,pH由6.78升到9.48,电导率先增加到651.8 μS/cm后降至375.7 μS/cm,速效磷含量从52.1 mg/kg降至16.9 mg/kg,全镁含量从1.403 g/kg升至9.015 g/kg.结论]构树对镁具有较强耐受能力,并对生长土质要求低,在不同程度破损土质中均能健康生长,在修复菱镁矿区镁污染土地方面具有相当大的潜力.

Ecological Adaptability of Broussonetia papyrifera in Damaged Land of Magnesite Mining Area

Objective] Effects of magnesite powder dust on soil physical and chemical properties and tolerance of Broussonetia papyrifera on magnesium dust polluted soil were studied.Method] Magnesite spraying simulation in laboratory and waste rock field mixing artificially were used.Result] Broussonetia papyrifera could grow better when the content of magnesium dust was lower than 10％ （w/w,dust/（dust ＋ soil））.The biomass of Broussonetia papyrifera was 3.46 g as the magnesium content was 4.17 g/kg,and was larger than that on clean soil of 2.81 g.Broussonetia papyrifera could grow in the worse soil,and the maximum biomass reached 6.12g,when the ore content in soil was 25％,3.31 g over 2.81 g obviously from the clean soil.Magnesium dust addition also changed the physical-chemical properties of soil,pH increased from 6.78 to 9.48,the conductivity first increased to 651.8 μ S/cm following decreased to 375.7 μS/cm,available phosphorus content decreased from 52.1 mg/kg to 16.9 mg/kg,and total magnesium content increased from 1.403 g/kg to 9.015 g/kg.Conclusion] Broussonetia papyrifera showed a great tolerance to magnesium dust.It could grow well in different damaged soil,and had a great potential in remediation of magnesium dust polluted soil.