湘中丘陵区不同经营类型毛竹林土壤微生物量碳动态

Soil microbial biomass carbon dynamics of Phyllostachys edulis forests under different managing patterns in the hilly region of central Hunan,southern China

对湘中丘陵区毛竹笋用林（I）、笋材兼用林（Ⅱ）、材用林（HI）等不同经营类型林分土壤微生物量碳（SMBC）含量、储量的垂直分布、季节动态及与土壤温度、湿度的关系进行了研究。结果表明：笋用林、笋材兼用林和材用林土壤平均SMBC含量分别为18．92～118．42、21．19～133．66和19．56～119．46mg／kg，储量为0．12～0．74、0．14～0．91和0．11—0．70t／hm^2；在垂直分布上，不同类型毛竹林碳含量、碳储量随土壤深度增加而下降，0～20cm土层是SMBC的主要分布区；在季节动态上，不同类型毛竹林碳含量、碳储量均以7月最高，1月最低；在一定范围内，土壤温度上升、湿度增加有利于促进SMBC含量、储量增加，SMBC与土壤温度的相关性达极显著水平；土壤温度对SMBC的影响符合幂指数模型，湿度与SMBC的回归关系为非线性。

Based on plot data of shoot utilizing （ I ）, shoot and timber utilizing （ II ） and timber utilizing （ m ） of Phyllostachys edulis forests located at the hilly region in central Hunan, a study had been carried out on vertical distribu- tion, seasonal dynamics soil microbial biomass carbon （SMBC） concentrations and storages as well as their relationship with soil temperature and moisture in above three typical managing patterns. The results showed that the average SMBC concentrations of type I , II and III were 18.92 - 118.42 mg/kg, 21.19 - 133.66 mg/kg and 19.56 - 119.46 mg/kg respectively, and storages were 0.12 -0.74 t/hm2, 0.14 -0.91 t/hm2 and 0.11 -0.70 t/hm2 respectively. The verti- cal distribution showed that SMBC concentrations and storages decreased with the increase of soil depth in three different forests, moreover, the soil layers of 0 - 20 cm were the main distribution of SMBC. For seasonal dynamics, SMBC con- centrations and storages were the highest in July and the lowest in January. SMBC was significantly positively related with soil temperature and their relationship could be described well by power exponent. However, there existed a nonlin- ear relationship between SMBC and soil moisture. It was effective in some extent for increasing SMBC concentrations and storages along with soil temperature and moisture rise increase.