林火对土壤细根系生物量影响的研究

Effect of Forest Fire on Fine Root in Soil

通过对大兴安岭新林林业局 2 0年不同年份 10块火烧迹地进行调查取样和室内分析 ,发现不同年限不同强度的火烧迹地土壤中细根系 (直径 <2 m m)生物量的变化不同 :( 1)火烧后 ,细根系的生物量均有所增加 ,且高强度火烧后增加最显著 ,其次是低强度火烧 ,中强度火烧最不明显 ;( 2 )低强度火烧 ,当年细根系生物量增加最多 ,以后逐年下降 ,至火烧 6年后基本达到未烧前的水平 ,以后随着火烧后年限的增加 ,细根系生物量又有逐年增加的趋势 ;中强度火烧对细根系生物量增加的影响呈现不规律的变化 ;而高强度火烧对细根系生物量的影响除了在当年比较显著以外 ,在火烧 10年、 2 0年后最显著 ;( 3 )无论何种强度的当年火烧迹地 ,一场雨过后 。

Based on the field investigation, sampling and lab analysis to ten burned forest soil plots in Xinlin Forest Bureau in Daxing′anling forest region, this paper finds that the fine root biomass(D<2 mm) is different in different fire intensity and after-fire-period plots:(1)the fine root biomass is increased after fire, and it is the most outstanding after high intensity fire,and then is the low intensity fire, the moderate intensity fires is the most unremarkable;(2)after low intensity fires, the increment of the fine root biomass is the highest in present year, then decreasing gradually in the years followed. It is reduced to the same level compared with the unburnt site after 6 years. It has then an increasing tendency in the years followed. The influence of moderate intensity fires on the fine root biomass presents an irregular change. But the influence of high intensity fires is most outstanding after 10 or 20 years;(3)it has a fine root biomass increment following a rainfall after any fires.