密度调控对长白落叶松人工林土壤呼吸的影响

发布时间：2018-06-22 17:42

本文选题：密度调控 + 长白落叶松人工林　；参考：《北京林业大学学报》2017年06期

【摘要】：为探明密度调控对北温带森林土壤呼吸的影响机制,以长白落叶松人工林为研究对象,选择4种林分密度P1(300~350株/hm2)、P2(500~550株/hm2)、P3(600~650株/hm2)和P4(850~900株/hm2),使用LI-6400便携式土壤呼吸测定仪对其生长季(5—10月)土壤呼吸速率进行测定。结果表明:不同密度林分生长季土壤呼吸速率均呈现明显的季节动态,最高值均出现在8月末,最低值出现在10月中旬;不同密度林分生长季土壤呼吸速率及土壤累积CO2排放量均随林分密度增大而显著降低(P0.05)。不同密度林分土壤呼吸与土壤温度之间均呈极显著的指数相关(P0.001),但与土壤含水量之间相关关系不显著(P0.05);双因素模型拟合效果更优,土壤温度和含水量共同解释了土壤呼吸速率的73.1%~81.0%。土壤呼吸温度敏感系数Q10值表现为:在300~350株/hm2时最低(2.41),500~550株/hm2最高(3.32)。生物因子随着林分密度的增大而显著增大(P0.05),非生物因子均随林分密度增大而显著减小(P0.05);生长季土壤累积CO2排放量与生物因子达到极显著负相关(P0.001),与非生物因子均达到极显著正相关(P0.001)。逐步线性回归分析表明,生长季凋落物量、土壤有机碳、微生物生物量碳含量和土壤全氮含量与土壤呼吸的关系最为密切。综上所述,不同密度林分之间土壤温度及含水量、生物及非生物因子的差异是导致土壤CO2排放产生差异的主要原因。在森林经营管理中,为减小森林土壤CO2的排放量,应将林分密度设置为850~900株/hm2。
[Abstract]:In order to investigate the effect of density regulation on soil respiration in northern temperate forest, the plantations of Larix olgensis were studied. Four stand densities P1 (350 plants / hm ~ 2) P _ 2 (500 ~ 550 plants / hm ~ 2) P _ 3 (600 ~ 650 / hm ~ 2) and P _ 4 (850 ~ 900 / hm ~ 2) were selected. The soil respiration rate in growing season (May to October) was measured by LI-6400 portable soil respiration meter. The results showed that the soil respiration rate of different density stands showed obvious seasonal dynamics, the highest values appeared at the end of August, and the lowest values appeared in the middle of October. Soil respiration rate and soil cumulative CO _ 2 emission decreased with the increase of stand density (P0.05). There was a significant exponential correlation between soil respiration and soil temperature (P0.001), but there was no significant correlation between soil moisture content and soil respiration (P0.05). The soil temperature and water content explained the soil respiration rate by 73.1% and 81.0%. The soil respiration temperature sensitivity coefficient Q10 was the lowest (2.41) at 300 ~ 350 plants / hm ~ (2) and the highest (3.32) at 550 / hm ~ (2) / hm ~ (2) of soil respiration temperature. Biological factors increased significantly with the increase of stand density (P0.05), abiotic factors significantly decreased with the increase of stand density (P0.05); soil cumulative CO2 emissions in growing season were negatively correlated with biological factors (P0.001), and were significantly correlated with abiotic factors. Significant positive correlation was achieved (P0.001). Stepwise linear regression analysis showed that litter amount, soil organic carbon, microbial biomass carbon content and soil total nitrogen content were the most closely related to soil respiration in growing season. To sum up, the difference of soil temperature, water content, biological and abiotic factors among different density stands is the main reason for the difference of soil CO2 emission. In order to reduce CO _ 2 emission from forest soil, stand density should be set to 850,900 trees / hm ~ (2) in forest management.
【作者单位】：东北林业大学生态研究中心;黑龙江省森林工程与环境研究所;黑龙江省森林生态与林业生态工程重点实验室;黑龙江牡丹江森林生态系统国家定位观测研究站;
【基金】：黑龙江省科技攻关项目(GC12C203) 黑龙江省林业科学院青年基金项目(N201414) 国家自然科学基金面上项目(41275154)
【分类号】：S714

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