南亚热带马尾松-红锥混交林与其纯林对土壤微生物生物量碳和氮的影响比较

Effects of the Monocultures and Pinus massoniana×Castanopsis hystrix Plantations on Soil Microbial Biomass Carbon and Nitrogen in Southern Subtropical China

通过对南亚热带马尾松与红锥人工纯林及其混交林的土壤微生物生物量碳(MBC)和氮(MBN)及土壤微生物生物量碳与有机碳(SOC)之比(MBC/SOC)和微生物生物量氮与全氮(TN)之比(MBN/TN)的分析,为南亚热带丘陵地区人工造林的树种选择与配置模式提供科学参考。在马尾松林、红锥林及马尾松-红锥混交林随机设置样地,并按对角线法采集样地不同土层(0~20、20~40和40~60 cm)的土样,采用氯仿熏蒸浸提法测定土壤MBC和MBN,利用方差分析和Pearson相关分析检验不同林分与土层对土壤MBC、MBN、MBC/SOC和MBN/TN的影响及其主导的土壤理化性质因子。结果显示:(1)3个研究林分之间的土壤MBC、MBN、MBC/SOC及MBN/TN无显著差异,但各林分的土壤MBC和MBN均随土壤深度增加而递减,而土壤MBC/SOC与MBN/TN随土壤深度增加的变化趋势因林分而异。(2)Pearson相关分析表明,林分土壤MBC、MBN与土壤SWC、SOC及SOC/TN呈极显著正相关,与pH值呈极显著负相关(P<0.01);土壤MBN/TN与SOC、SOC/TN呈显著正相关,而与pH值显著负相关;土壤MBC/SOC与所有土壤理化性质参数均无显著相关关系(P>0.05)。可得结论:在南亚热带地区营建马尾松-红锥混交林与其纯林对土壤MBC和MBN的影响无明显差异。

Through the analysis of soil microbial biomass carbon(MBC)and nitrogen(MBN),the ratio of soil biomass carbon to organic carbon(MBC/SOC)and the ratio of microbial biomass nitrogen to total nitrogen(MBN/TN)of P.massoniana and C.hystrix plantations and their mixed plantations in the southern subtropical China,a scientific reference was provided for the selection and allocation model of tree species about artificial afforestation in the hilly area of the studied region.Sample plots were randomly set in P.massoniana plantation,C.hystrix plantation and P.massoniana×C.hystrix mixed plantations.Soil samples of different soil layers(0-20 cm,20-40 cm and 40-60 cm)were collected by diagonal method,and soil MBC and MBN were determined by chloroform fumigation extraction method.The effects of different stands and soil layers on soil MBC,MBN and Effects of MBC/SOC and MBN/TN and their dominant soil physical and chemical properties.The results showed that there was no significant difference in soil MBC,MBN,MBC/SOC and MBN/TN among the three study stands,but the soil MBC and MBN of each stand decreased with the increase of soil depth,while the change trend of soil MBC/SOC and MBN/TN with the increase of soil depth varied from stand to stand.Pearson correlation analysis showed that MBC and MBN in stand soil had a very significant positive correlation with soil SWC,SOC and SoC/TN,and a very significant negative correlation with pH(P<0.01);Soil MBN/TN was significantly positively correlated with SOC and SOC/TN,but negatively correlated with pH;There was no significant correlation between soil MBC/SOC and all soil physical and chemical properties(P>0.05).Significant difference was not found in soil MBC and MBN between P.massoniana×C.hystrix and its pure plantations in south subtropical area.