三峡库区马尾松细根生产和周转及其影响因子

Fine root production and turnover of Pinus massoniana and their influencing factors in the Three Gorges Reservoir Area,China

采用连续根钻法、分解袋法、分室通量模型法计算三峡库区马尾松细根的年生产量和周转率,分析细根生产量和周转率与各影响因子的关系.结果表明:马尾松<0.5、0.5~1和1~2 mm细根年均生物量分别为0.29、0.59、0.76 t·hm^(-2),细根年生产量分别为0.13、0.49、0.37t·hm^(-2),细根年周转率分别为1.49、1.01、0.40 a^(-1).各影响因子对不同径级细根生产与周转的影响不同.土壤温度、土壤钙含量显著影响<0.5 mm细根生产量与细根周转,且土壤温度解释生产量和周转率32.8%和25.0%的变异,土壤钙含量解释65.6%和73.1%的变异;细根生物量与细根生产量呈显著正相关,细根生物量分别解释<0.5、0.5~1和1~2 mm细根生产量41.0%、41.1%和54.5%的变异;细根P、K含量与<0.5 mm细根生产量具有显著相关性,分别解释<0.5 mm细根生产量32.2%、39.2%的变异.<0.5 mm细根与各影响因子的关系最为密切,土壤温度、土壤钙含量是细根生物量的主要影响因子.

In this study, the annual production and turnover rate of fine root of Pinus massoniana in Three Gorges Reservoir Area were calculated using sequential soil core, litterbag and compartment flux model methods, and the relationship between fine root production, turnover rate and factors was analyzed. The results showed that the annual mean biomass of 〈0.5, 0.5-1 and 1-2 mm fine root was 0.29, 0.59 and 0.76 t ·hm^-2, annual production was 0.13, 0.49, 0.37 t ·hm^-2, and annual turnover rate was 1.49, 1.01, 0.40 a^-2 , respectively. The effects of factors on production and turn- over of fine roots with different diameters were different. Soil temperature and soil Ca content had significant effects on production and turnover of 〈0.5 mm fine roots, and soil temperature explained the variation of production and turnover by 32.8% and 25.0%, and soil Ca content explained by 65.6% and 73.1%, respectively. There was a positive relationship between fine root biomass and fine root production, and the biomass of fine root explained 41.0%, 41.1% and 54.5% of variation in fine root production for 〈0.5, 0.5-1 and i-2 mm fine roots, respectively. P and K contents of fine roots correlated significantly with 〈 0.5 mm fine root production, and explained 32.2% and 39.2% of the variation of 〈0.5 mm fine root production, respectively. The fine root with diameter 〈0.5 mm was most closely associated with soil factors, and soil temperature and soil Ca content were the main factors affecting fine root biomass.