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土壤溶解性有机碳(DOC)是土壤有机碳库的活性组分,DOC降解影响土壤有机碳的迁移转化过程、生态系统的养分平衡和微生物的能源供给。当前大气氮沉降的增加是影响我国南方森林生态系统碳固定过程的重要因素,已引起各方广泛关注。论文基于中亚热带红壤丘陵区三种人工针叶林过去5 a的施肥试验,重点分析了不同树种土壤DOC季节及0~30 cm土壤垂直剖面上的动态变化特征,对比分析了施肥对于不同人工林土壤DOC的影响。研究发现:1 DOC浓度季节变化:湿地松林为秋季>春季>夏季>冬季;马尾松林为秋季>春季>冬季>夏季;杉木林为秋季>夏季>冬季>春季。DOC浓度剖面变化特征如下:湿地松林为10 cm>20 cm>30 cm;马尾松林为20 cm>10 cm>30 cm;杉木林为20 cm>30 cm>10 cm。2湿地松林土壤DOC浓度:施P肥>对照>施N+P肥>施N肥;马尾松林土壤DOC浓度:对照、施N+P肥>施N肥>施P肥;杉木林:对照>施P肥>施N肥、施N+P肥。论文通过研究不同施肥条件下人工林DOC浓度在季节和剖面上的变化,可为了解大气氮沉降对中亚热带人工针叶林土壤DOC的可能影响提供重要的科学依据。
Soil dissolved organic carbon (DOC) is the active component of soil organic carbon pool. DOC degradation affects the process of soil organic carbon migration and conversion, ecosystem nutrient balance and microbial energy supply. At present, the increase of atmospheric nitrogen deposition is an important factor that affects the carbon fixation process of forest ecosystems in southern China and has drawn wide attention from all parties. Based on the fertilization experiments of three artificial coniferous forests in the red soil hilly region of Central Asia subtropics in the past five years, the paper mainly analyzed the DOC seasons and the dynamic variation characteristics of 0-30 cm soil vertical profiles in different tree species, and compared the effects of fertilization on different plantations Impact of soil DOC. The results showed that: 1) Seasonal changes of DOC concentration: Slash pine forests were in autumn> spring> summer> winter; masson pine was in autumn> spring> winter> summer; fir forest was in autumn> summer> winter> spring. The characteristics of DOC concentration profiles were as follows: 10 cm> 20 cm> 30 cm for Pinus elliottii and 20 cm> 10 cm> 30 cm for Pinus massoniana and 20 cm> 30 cm> 10 cm for Chinese fir plantation. 2 DOC concentration in Pinus elliottii plantation: application of P fertilizer> control> application of N + P fertilizer> application of N fertilizer; DOC concentration in Pinus massoniana forest: control, application of N + P fertilizer> application of N fertilizer> application of P fertilizer; Chinese fir plantation: Shi P fertilizer> N fertilizer, fertilizer N + P. Papers through the study of different fertilization conditions DOC concentration in the plantation and section changes in the season, the understanding of atmospheric nitrogen deposition on the Mid-subtropical artificial coniferous soil DOC possible to provide an important scientific basis.