摘要
基于温带森林演替不同阶段2种林分矿质层不同深度土壤(0~10 cm、10~20 cm和20~30 cm)以及有机层样品,研究冷水、热水、冷CaCl_2和热CaCl_2溶液以及冷K_2SO_4溶液浸提这些样品的溶解性有机质含量变化规律,并分析它们各自与微生物碳和微生物氮有效性之间的关系。2种林分有机层样品溶解性有机质、微生物碳和氮以及总有机碳和总氮含量均显著高于矿质层土壤,森林演替顶级群落的阔叶红松混交成熟林矿质层土壤(0~10cm)显著高于次生白桦林,且随土层深度的增加呈现递减趋势。5种浸提剂提取的溶解性有机碳和溶解性有机氮含量表现为热水>热CaCl_2溶液>冷K_2SO_4溶液>冷水>冷CaCl_2溶液,不同浸提剂对两种林分有机层样品和0~10 cm矿质层土壤浸提的溶解性有机质含量存在显著性差异,而对10~20 cm和20~30 cm土壤差异性不显著。阔叶红松混交成熟林和次生白桦林矿质层土壤微生物碳/土壤总有机碳含量比例范围分别为0.94%~1.84%和2.56%~2.86%,土壤微生物氮/土壤总氮含量比例范围分别为1.23%~3.23%和2.06%~3.72%,并随土壤深度的增加而减少。相关分析结果显示,5种浸提剂所浸提的林地有机层和矿质层样品溶解性有机质含量分别与微生物碳/总有机碳和微生物氮/总氮比例呈显著的正相关关系,热水提取的相关系数最大。因此,热水浸提剂较适用于研究森林土壤活性有机质含量,这为研究不同立地条件下森林土壤溶解性有机质含量及其生物有效性以及对环境变化的响应规律提供重要支撑。
Samples of forest organic layer and mineral soils（e.g. 0-10, 10-20 and 20-30 cm） in two temperate forests with different forest succession stages were used to investigate the changes in content of dissolved organic matter（DOM） that was extracted by five extractants, i.e. cold water, hot water, cold CaCl2 solution, hot CaCl2 solution and cold K2SO4 solution, and to analyze the relationships of DOM content obtained by these extracts between soil microbial biomass carbon and nitrogen availability. Content of DOM, microbial biomass carbon and nitrogen, total organic carbon and total nitrogen in forest organic layers at two forest succession stages was significantly higher than that in forest mineral soils. Compared with secondary white birch forest（WBF） soil, there was a significant increase in all the C and N pools in the 0 -10 cm soil sampled from mature broadleaf and Korean pine mixed forests（BKPF） which belong to the forest succession climax community. In so far as the five extractants above-mentioned, by which dissolved organic carbon（DOC） and dissolved organic nitrogen（DON） in forest organic layer and mineral soils were extracted, the extracting strength followed the order as water hot CaCl2 solution cold K2SO4 solutioncold watercold CaCl2 solution; and the extracting agents were notably different in extraction of the organic layer and（0-10 cm） mineral soils of two forest stands but not in extraction of the mineral soils1 with depth ranges of 10-20 cm and 20-30 cm. The microbial biomass carbon-to-total organic carbon（MBC/TOC） concentration ratio in the mineral soils of BKPF and WBF ranged from 0.94% to 1.84% and from 2.56% to 2.86%, respectively, while the microbial biomass nitrogen-to-total nitrogen（MBN/TN） concentration ratio ranged from 1.23% to 3.23% and from 2.06% to 3.72%, respectively. Both MBC/TOC and MBN/TN ratios in the BKPF and WBF decreased with increase soil depth. In addition, a correlation analysis showed that there existed significantly positive relationships
出处
《环境科学与技术》
CAS
CSCD
北大核心
2017年第11期1-7,16,共8页
Environmental Science & Technology
基金
国家自然科学基金(41275166
41321064
41575154)
关键词
森林土壤
浸提剂种类
溶解性有机碳
溶解性有机氮
微生物量
forest soil
extractants type
dissolved organic carbon
dissolved organic nitrogen
microbial biomass
