绿肥对集约经营毛竹林土壤微生物特性的影响

毛竹集约经营是目前普遍采用的获得高经济效益的经营措施，然而长期集约经营导致土壤质量特别是生物学性质下降。为了探索改善集约经营毛竹林土壤生物学性质的途径和措施，2007年开展了不同绿肥对毛竹林土壤微生物特性的影响试验。布置了对照、白三叶、大绿豆、黑麦草及大绿豆黑麦草混播、龙爪稷等6个处理的为期7周的盆栽试验。结果表明:绿肥处理均能改善土壤微生物特性，大绿豆处理的土壤微生物量碳最高而对照最低，二者分别明显高于或低于其他绿肥处理，其余几个处理之间无明显差异。绿肥处理提高土壤微生物利用碳源能力(AWCD)，其中最好的是豆、麦混播和白三叶2个处理；大绿豆处理最差；豆、麦混播及白三叶与大绿豆及对照之间差异显著。豆、麦混播的土壤微生物Shannon 多样性指数高于其他处理。白三叶和豆、麦混播的土壤微生物McIntosh指数显著高于其他处理。通过AWCD、Shannon指数和McIntosh指数3个参数比较发现，McIntosh指数能较好地反映微生物的功能多样性。大绿豆、黑麦草混播及白三叶对改善土壤微生物特性效果最好。考虑到白三叶的耐阴性更好，建议毛竹林下种植白三叶来改善土壤的生物学性质。 

Effects of green manure on soil microbial properties of Phyllostachys pubescens stands under intensive management

Intensive management of bamboo (Phyllostachys pubescens) stands is commonly practiced to yield high profits. Long-term intensive management may have adverse effects on soil quality, especially soil biological properties. To evaluate the potential of using green manure to improve soil microbial properties of P. pubescens stands, a pot trial was conducted over a period of seven weeks. The treatments included the control (no vegetation), white clover, green gram, rye grass, the mixture of green gram and rye grass, and elousine coracana. Concentrations of soil microbial biomass carbon (MBC) in all green manure treatments were significantly (P<0.05) greater than in the control. There was no significant difference in soil MBC concentrations between the green manure treatments except green gram treatment, which was significantly great (P<0.05). The ability of carbon utilization of soil microbial communities measured by Biolog Eco-microplate characterized as average well color development (AWCD) was improved by green manure treatments. The AWCD measurements of white clover, and the mixture of green gram and rye grass treatments were significantly (P<0.05) greater than those of other 3 manure treatments. Shannon index of the mixture of green gram and rye grass treatment was significantly (P<0.05) greater than those of the other treatments. McIntosh indexes of the white clover, and the mixture of green gram and rye grass treatments were significantly (P<0.05) greater than those of the other treatments. Among the AWCD, Shannon index and McIntosh index, McIntosh index was found to be the best indicator of the soil microbial functional diversity in the current study. White clover and the mixture of green gram and rye grass treatments were the most efficient in improving soil microbial properties. We recommend planting white clover under P. pubescens stands to improve soil microbial properties because of its superior shade tolerance.