摘要
为了解土地利用方式对土壤有机碳库的影响，研究了湘中丘陵区6种土地利用方式（石栎＋青冈次生林、杉木人工林、毛竹林、苗圃、农用旱地、水田）土壤水溶性有机碳（DOC）含量及其季节动态，分析了土壤DOC含量与土壤自然含水率、碳（C）、氮（N）含量之间的关系。结果表明：土壤DOC含量随土壤深度增加而下降，秋季土层之间差异最小，土壤DOC分配比例随土壤深度增加而增大；不同土地利用方式土壤DOC含量差异显著，与石栎＋青冈次生林相比，毛竹林、杉木人工林、水田、农用旱地、苗圃依次下降了10％～12％、11％～12％、13％-19％、18％～25％和37％～42％，夏季不同土地利用方式之间差异最大。不同土地利用方式土壤DOC含量季节变化明显，均表现为：春、夏、冬季较高，秋季最低，秋季与春、夏、冬季之间差异显著；土壤DOC含量与土壤自然含水率、TOC、MBC、ROC、MOC、全N、水解N含量呈显著或极显著正相关。可见，土地利用方式显著影响土壤DOC含量及其空间分布，次生林转变为人工林或农用地后，土壤DOC含量明显下降。
In order to understand the effects of land-use patterns on soil organic carbon （SOC） pool, a study was conducted to examine the seasonal variation of soil dissolved organic carbon （DOC） and its correlation with soil moisture content, carbon （C） and nitrogen （N） concentrations in six adjacent land use types： （1） Lithocarpus glaber ＋ Cyclobalanopsis glauca secondary forest, （2） Cunninghamia lanceolata plantation, （3） Phyllostachys edulis forest, （4） seedling nursery land, （5） slope cropland, and （6） paddy field in a hilly area of central Hunan, China. The results showed that DOC concentrations decreased with soil depth and with the minimum difference of DOC concentrations between soils layers occurring in autumn, while the proportion of DOC increased with increasing the soil depth. Soil DOC concentrations were significantly dif- ferent among the land use types. Soil DOC concentrations decreased by 10% -12%, 11% - 12%, 13%-19%, 18%-25% and 37% -42% in P. edulis forest, C. lanceolata plantation, paddy field, slope cropland and seedling nursery land, respectively, as compared with L. glaber ＋ C. glauca secondary forest. The differences in DOC concentration among different land use types were maximum in summer. Seasonal variations in DOC concentration were considerable but a similar change pattern was found in the six land use types. Soil DOC concentrations were signif- icantly higher in spring, summer and winter than in autumn. Positive correlations were found between DOC concentrations and soil moisture content, TOC, MBC, ROC, MOC, total N, and available N. These results demonstrated that land-use patterns significantly affected soil DOC con- centration and its spatial distribution. Soil DOC concentrations were significantly reduced when secondary forests were converted to plantations or agricultural lands.
出处
《生态学杂志》
CAS
CSCD
北大核心
2014年第8期2065-2071,共7页
Chinese Journal of Ecology
基金
国家林业公益性行业科研专项(201304317)
国家林业局林业科技推广项目([2012]61号)资助
关键词
湘中丘陵区
土地利用方式
土壤水溶性有机碳
季节变化
hilly area of central Hunan
land-use types
soil dissolved organic carbon
seasonalvariation
