改良剂对铜矿尾矿砂与菜园土混合土壤性质及黑麦草生长的影响

用蒙脱石、稻草、鸡粪作为改良剂 ,研究不同改良剂对铜矿尾矿砂与菜园土混合土壤pH、有效态重金属含量、脲酶和磷酸酶活性以及混合土壤上种植的黑麦草生长的影响。结果表明 :添加蒙脱石对不同生长期黑麦草的生长量没有显著影响 ;使用稻草和鸡粪处理尽管在开始阶段不利于黑麦草 (第 1茬和第 2茬 )的生长 ,但随时间延长 ,黑麦草的生物量 (第 3茬和第 4茬 )明显增加 ,表现出很好的后效。黑麦草的根重与鸡粪的添加量关系显著 ,施用稻草的纯尾矿砂处理组 (处理 2 2 )根重最大 ,而且蚯蚓只能在使用适量稻草的处理条件下才能在混合土壤中生长。土壤酶的分析发现 ,磷酸酶的活性除了在蚯蚓能够生长的处理组表现出较高外 ,其它处理之间无明显差异 ,但脲酶的活性则随着稻草和鸡粪施用量的增加而显著提高。各处理之间土壤的 pH值变化不大。添加稻草减少了土壤中有效态重金属的含量 ,而使用鸡粪处理明显增加了土壤中包括铜、铅和锌等有效态重金属的含量 ,说明在施用含有重金属的畜禽粪便时务必小心谨慎 ,以防二次污染。

Effects of soil amendments on the characters of mixed soil(copper mine tailing and garden soil)and on the growth of ryegrass on it

Effects of different soil amendments (montmorillonite, rice straw and chicken manure) on the characters of mixed soil (copper mine tailing and garden soil) and on the growth of ryegrass on the soil were studied. The results show that montmorillonite had no significant effect on ryegrass at various growth stages, but rice straw and chicken manure, though inhibitive to ryegrass growth in terms of biomass of the first and second cuttings, increased the yield of the third and fourth cuttings significantly, showing enormous residual effect, which is mainly due to their slow decomposition in soils. Earthworms can only grow in soil with rice straw applied at a suitable rate. No obvious difference in soil phosphatase was observed between treatments except for the one, which was suitable for growth of earthworm. Rice straw and chicken manure increased urease activity. The treatments using rice straw decreased the quantity of available metals in soil, but the ones using chicken manure increased available metal concentration, suggesting that it must be careful in using chicken manure, containing large amounts of metals, as organic fertilizer.