接种蚯蚓与添加凋落物对杨树人工林土壤理化性质和微生物生物量的影响

Effects of earthworm inoculation and litter addition on soil physical and chemical properties and soil microbial biomass in poplar plantation

以江苏省东台市20 a林龄的杨树人工林为研究对象,共设置6个处理:空白对照(CK),杨树凋落物表施(杨树叶平铺于样方表面,T1),杨树凋落物混施(凋落物与土壤混合均匀,T2),接种蚯蚓(T3),杨树凋落物表施+接种蚯蚓(T4),杨树凋落物混施+接种蚯蚓(T5).对土壤微生物生物量碳(SMBC)和土壤微生物生物量氮(SMBN)含量的动态变化进行1 a的监测,同时测定土壤基本理化指标,分析土壤微生物生物量与土壤理化指标之间的相关性.结果表明:接种蚯蚓与添加凋落物可以降低土壤pH值和容重,提高溶解性总氮(DTN)和溶解性有机碳(DOC)含量,处理效果为T5>T4>T3>T2>T1;接种蚯蚓可以提高SMBC和SMBN含量,其中T5处理的提升效果最为显著,SMBC和SMBN增幅分别达到36.58%和24.98%,T4处理的SMBC/SMBN值增幅最大,达10.35%;此外,土壤DTN和DOC含量对本区域SMBC和SMBN含量起促进作用.

To elucidate the function of earthworm and leaf litter on the nutrient cycling of soil ecosystem in poplar plantation,6 treat-ments,including control(CK),poplar leaf litter surface application(T1),mixed application of poplar leaf litter and soil(T2),earthworm inoculation(T3),poplar leaf litter surface application+earthworm inoculation(T4)and poplar leaf litter mixed application+earthworm inoculation(T5)were set up in a 20-year-old poplar plantation in Dongtai Forest Center of Jiangsu Province.Soil microbi-al biomass carbon(SMBC)and soil microbial biomass nitrogen(SMBN)were monitored for a year,and soil physical and chemical in-dexes were determined,and the relationship between soil physiochemical properties and microbial biomass were further analyzed.The results showed that earthworm inoculation and litter addition lowered soil pH and bulk density,and increased the contents of dissolved total nitrogen(DTN)and dissolved organic carbon(DOC).The efficacy of 5 treatments were ranked in the order of T5>T4>T3>T2>T1.Earthworm inoculation overall enhanced SMBC and SMBN levels.Among all the treatments,T5 resulted in the most significant im-provements at SMBC and SMBN contents by 36.58%and 24.98%rises,respectively,while T4 showed the highest increase in SMBC/SMBN ratio at 10.35%.Besides,DTN and DOC contributed to higher SMBC and SMBN levels in this region.