衡阳紫色土丘陵坡地木荷人工林微生物生物量碳(MBC)的时空动态

为了探讨土壤微生物量碳(Microbial Biomass Carbon, MBC)在衡阳紫色土丘陵坡地木荷(Schima superba)人工林生态系统碳循环的作用，利用氯仿熏蒸法测定了木荷人工林的MBC，研究其时空动态及其与土壤有机碳(Soil Organic Carbon, SOC)的关系。结果表明：（1）中龄林(Middle-aged plantation, MAP)与成熟林(Mature plantation, MP)木荷人工1—2月、3—4月、5—6月、7—8月、9—10月、11—12月的MBC存在明显差异(P＜0.05)，在整个生长过程中出现2个峰值，第1峰出现在3—4月，第2峰出现在9—10月，最低值均出现在11—12月；（2）MAP与MP木荷人工林的MBC存在明显垂直分布规律，在0~20 cm、20~40 cm、40~60 cm各土层中，以0~20 cm土层的MBC最大，20~40 cm土层的MBC次之，40~60 cm土层的MBC最小，且各土层的MBC的差异也均达到显著水平(P＜0.05)；（3）木荷人工林MBC与SOC呈线性关系：y=21.654x+54.128(R2=0.984, P＜0.01)；（4）在MAP与MP木荷人工林中，土壤微生物熵(MBC/SOC)随土层深度的增加而升高，说明SOC逐渐由0~20 cm土层向40~60 cm土层转移，土壤处于碳积累状态，土壤呈碳汇功能。

Spatio-temporal Dynamics of Microbial Biomass Carbon (MBC) in Schima superba on Sloping-land with Purple Soils in Hengyang

In order to explore the role of microbial biomass carbon （MBC） in ecosystem carbon cycle of Schima superb plantations in the sloping-land with purple soils in Hengyang. The time and space distribution dynamics of MBC in middle-aged plantation （MAP） and mature plantation （MP） was studied by using the chloroform fumigation extraction method. And the relationship between MBC and soil organic carbon （SOC） were also analyzed. The results showed that：（1） there was significant difference of MBC in MAP and MP in the month of 1-2, 3-4, 5-6, 7-8, 9-10 and 11-12 （P〈0.05）, and there were 2 peaks in the whole year, the first peak value was at the month of 3-4, the second peak value was at the month of 9-10, MBC reached the minimum value at the month of 11-12;（2） There was also significant difference of MBC in MAP and MP in the soil layers of 0-20 cm, 20-40 cm, 40-60 cm, and the maximum was in the layer of 0-20 cm, the minimum in the layer of 40-60 cm, which exhibited a vertical distribution pattern;（3） The relationship between MBC and＆nbsp;SOC was： y=21.654x＋54.128 （R2=0.984, P〈0.01）; （4） The MBC/SOC increased with increase of soil horizons showed SOC transferred gradually from the layer of 0-20 cm to the layer of 40-60 cm and soil C was in accumulated status, the results showed that the soils of MAP and MP were C pool.