杨树和桤木落叶混合分解对土壤微生物生物量的影响

Effects of the decomposition of poplar and alder mixed leaf litters on soil microbial biomass

通过室内培养,研究了杨树和江南桤木落叶混合分解过程中两种落叶的混合比例及落叶添加方式对土壤微生物生物量的影响.结果表明:落叶混合比例对土壤微生物生物量碳(MBC)、氮(MBN)均有显著的影响.培养30d,江南桤木落叶比例为50%以上的土壤MBC和MBN显著高于纯杨树落叶处理及对照;75d时,江南桤木落叶比例≥40%的土壤MBC和≥30%的土壤MBN均显著高于纯杨树落叶处理及对照;135d后,江南桤木落叶比例≥20%的土壤MBC和≥40%的土壤MBN均显著高于纯杨树落叶处理及对照.不同混合比例的土壤MBC/MBN无显著差异,总体呈前期增长后期下降的变化趋势.杨树和江南桤木落叶混合分解对土壤MBC和MBN有显著的协同促进作用.在整个培养过程中,落叶添加方式对土壤MBC、MBN和MBC/MBN无显著影响.

An incubation test was conducted to study the effects of the decomposition of poplar and trabeculate alder leaf litters with different mixed ratios and under different application ways on soil microbial biomass carbon（MBC） and nitrogen（MBN）.The mixed ratio of the litters had significant effects on soil MBC and MBN.On the 30th day of incubation,soil MBC and MBN were significantly higher in the treatments with ≥50% of alder litter than in the treatment with poplar litter only and the control.On the 75th day of incubation,the soil MBC in the treatments with ≥40% of alder litter and the soil MBN in the treatments with ≥30% of alder litter were significantly greater than those in the treatment with poplar litter only and the control.After 135 days incubation,soil MBC and MBN were significant higher in the treatments with ≥20% and ≥40% of alder litter than in the treatment with poplar litter only and the control,respectively.There was no significant difference in the soil MBC/MBN between the treatments with different mixed ratios of poplar and alder leaf litters and the control.Overall,soil MBC/MBN increased during the early period of incubation and decreased in the later period,suggesting that soil microflora changed during the decomposition of the litters.In the whole incubation period,the application ways of the litters had lesser effects on the soil MBC,MBN,and MBC/MBN,indicating that the addition ways of the litters did not affect soil microflora.