速生杨人工林对土壤碳氮含量及微生物生物量的影响

Organic Carbon and Nitrogen Contents and Microbial Biomass in Soils Under Rapid-Growth Poplar Plantation

以耕地为对照,在山东德州对4年生和7年生速生杨人工林下土壤有机碳、全氮和微生物生物量测定结果表明,土壤有机碳、全氮及微生物生物量主要集中分布在0—5和5—10 cm土层,林地土壤有机碳、全氮含量及微生物生物量都显著低于耕地,微生物生物量降低幅度比土壤有机碳和全氮大。10 cm以下土层检测指标在各样地间差异不显著。土壤有机碳与微生物碳、土壤全氮与微生物氮分别呈显著线性正相关,耕地转为林地后,土壤肥力下降。

Rapid-growth poplars have been planted in large areas because they can bring about huge economic benefit. Soil organic carbon（SOC）, total nitrogen （TN） and microbial biomass in soils of a farmland and two poplar woodlots, 4- year-old and 7-year-old, in Dezhou, Shandong Province were selected for comparison. Results show that microbial biomass, SOC and TN were all concentrated in the soil layers of 0 -5 cm and 5 - 10 cm, and significantly lower in the wood- lot soils than in the farmland soil, especially microbial biomass. But no significant difference was found between the three sites when it went down to 10 cm below in soil depth. Significant positive linear relationship was found between SOC and microbial biomass carbon, and between soil TN and microbial biomass N. Obviously once farmland is turned into rapidgrowth poplar plantation, soil fertility decreases.