火干扰对兴安落叶松林土壤轻组有机碳的影响

该研究基于土壤轻组有机碳在土壤碳循环中的重要作用，以大兴安岭林区兴安落叶松林土壤为研究对象，分析了火干扰后不同年份高强度火烧对土壤轻组有机碳的影响。用比重分离法对兴安落叶松林火干扰后3年（2008年）、火干扰5年（2006年）和火干扰后9年（2002年）样地及各对照样地的土壤样品进行测定。结果表明：不同年限火干扰后土壤轻组有机碳存在显著差异（P〈0．05）：火干扰后3年土壤轻组有机碳增加11．99％，而火干扰后5年土壤轻组有机碳含量减少了8．77％，火干扰后9年土壤轻组有机碳含量减少了6．27％，减少程度随着时间的推移有所下降。研究结果表明，土壤轻组有机碳与土壤含水率并无显著性关系；火干扰后3年和5年样地轻组有机碳与pH值呈显著性负相关，火干扰后轻组有机碳与土壤温度具有显著性负相关（P〈0．05）。火干扰后短期内土壤轻组有机碳表现出更加明显的季节动态性。该研究为进一步了解火干扰对北方森林土壤碳循环、碳平衡的影响机理以及火干扰后森林生态系统的碳效应提供基础数据。

Effects of Fire Disturbance on Soil Light Fraction Organic Carbon of Lar/x gmelinii Forest

Based on the vital function of LFOC in soil carbon cycle, the effects on soils burned from high-intensity wildfire in different years in the forests of Larix gmelinii were studied. Used a specific gravity separation method to examine dynamics of soil light fraction organic carbon （LFOC） of the soils burned in different years （2002, 2006 and 2008） and the soils unburned. The results showed that there was a significant difference between LFOC of soils bumed by fire in different years （ P 〈 0.05 ） ： the LFOC content of soils burned in 2008 increased by 11.99% ; the LFOC content of soils burned in 2006 decreased by 8.77% and burned in 2002 decreased by 6.27%. LFOC were not correlated with soil water content, but were significantly correlated with the pH value and the LFOC of soils burned in 2008 were very significant positive- ly correlation （P 〈 0.05 ） ; LFOC were also correlated with soil temperature. The seasonal dynamics of soil light fraction organic carbon within all the sample plots performed and especially more obvious after fire disturbance. The results of study provide basic data for researching the fire disturbance on the Northern forest soil carbon cycle, carbon balance mechanism and the carbon effect of forest ecosystem carbon after fire dis- turbance.