老龄杉木林土壤活性有机碳的动态变化

通过在福建南平西芹教学林场对老龄杉木林不同坡位土壤微生物生物量碳（MBC）和土壤可溶性有机碳（DOC）动态变化研究,结果表明：土壤MBC和土壤DOC具有明显的季节性波动,均在植物生长旺季维持在较低水平,在植物休眠季节维持在较高水平;在0—20cm的土层内,老龄杉木林不同坡位土壤MBC和土壤DOC的变幅分别在210.44—1418.90mg·kg^-1和8.24—38.54mg·kg^-1,两种易变有机碳的含量基本表现为中坡位〉下坡位〉上坡位;相关分析表明,土壤MBC与DOC之间的相关性达到显著水平,土壤MBC和DOC与土壤温度显著负相关,与土壤含水量、凋落物生物量和降雨量的相关性未达到显著水平,说明土壤MBC和土壤DOC的变化与土壤中的微生物活性、林木的生长以及根系分泌物等因素有关。

Dynamics of Soil Labile Organic Carbon in Old Growth Chinese Fir Forest

The experiment was conducted to investigate dynamic changes of soil MBC and DOC in a old growth Chinese fir forest.The results indicated that soil MBC and DOC have obvious seasonal fluctuation.Both of them maintenanced low level in plant growing season and high level in the dormant season.In 0—20 cm soil layer,the ranges of soil MBC and DOC on different slope positions of old growth Chinese fir forest were 210.44—1 418.90 mg·kg^-1 and 8.24—38.54 mg·kg^-1,respectively.The contents of two labile organic carbon on different slope positions followed the order of midslope〉 downslope 〉upslope.There was significant correlation between soil MBC and DOC.Also,soil MBC and DOC were both negatively related to temperature.However,there were no significant relationships among MBC,DOC,soil water content,litterfall amount,and rainfall.It suggested that the seasonal changes of soil MBC and DOC may be related to the availability of microbial activity,plant growth and root exudates.