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题名	紫色土坡耕地可溶性有机碳迁移过程研究
作者	李太魁
学位类别	博士
答辩日期	2011-05-27
授予单位	中国科学院研究生院
授予地点	北京
导师	朱波
关键词	紫色土 可溶性有机碳 吸附-解吸 淋失通量 坡耕地
其他题名	Research on dissolved organic carbon leaching process from slope cropland of purple soil
学位专业	自然地理学
中文摘要	可溶性有机碳（DOC）被认为是陆地生态系统和水生生态系统中重要的、非常活跃的化学组分之一，是养分和环境污染物移动的载体。但长期以来，研究者对DOC的迁移淋溶特性及其在土壤碳循环过程中的意义和环境效应的研究相对较少。紫色土农田土壤有机质含量普遍偏低，加之水土流失严重，导致土壤DOC偏低，可能影响农田生态系统养分循环过程及其生产力水平，而紫色土坡地农田DOC的迁移还缺乏深入研究。为深入认识紫色土紫色土有机碳循环过程，有必要研究紫色土DOC吸持与释放机制、紫色土坡地DOC的迁移途径与通量，为制定有效的农田土壤有机质管理，提升土壤碳汇功能提供科学依据。论文主要研究结果如下：（1）土地利用方式对紫色土DOC含量有显著的影响。各种利用方式土壤的DOC平均含量顺序为：菜地>果园>水田>林地>旱地。土壤DOC含量与有机碳、总氮、铵态氮和粘粒等养分之间呈显著的正相关关系。（2）不同类型紫色土对DOC的吸附容量有明显差异，酸性紫色土对DOC的吸附容量要强于中性紫色土和石灰性紫色土。DOC的吸附量与粘粒、活性铁铝氧化物呈显著正相关，而与土壤pH值呈显著负相关。土壤对DOC的吸附包括快吸附与慢吸附2个过程，0-0.5h内吸附速率最大，随着时间的推移，吸附速率逐渐减小，4-6h内基本达到吸附平衡。DOC解吸率与土壤粘粒、活性铁铝氧化物呈显著负相关，而与土壤pH值呈显著正相关。对DOC吸附能力强的土壤，其解吸能力会相应较弱。环境因素（温度）与外源因素（硫酸亚铁、磷酸盐）对土壤吸附DOC的容量影响显著。温度对土壤和DOC的吸附容量有明显的影响，随着温度升高（5～35℃），吸附容量呈现降低趋势，土壤解吸量增强。磷酸盐能阻止土壤对DOC的吸附，而亚铁盐能增加土壤对DOC的吸附。去除土壤部分有机质后，土壤对DOC吸附量有所增大。（3）紫色土区雨季降雨丰富，坡地壤中流发育，壤中流占径流总量的72.4%。紫色土坡地地表径流DOC平均流失负荷为1.33kg/hm2.a，而壤中流DOC平均淋失负荷达7.08 kg/hm2.a。壤中流DOC迁移是紫色土坡地DOC径流损失的主要途径。（4）紫色土坡地DOC淋失量与降雨量之间存在显著的正相关关系，淋失量随着降雨量的增加而增加。（5）紫色土坡地DOC淋失量随土层厚度增加而减少。20cm渗漏池DOC年淋失量达到2.56 kg/hm2，40cm渗漏池DOC年淋失量为2.27 kg/hm2，60cm渗漏池DOC年淋失量为2.11 kg/hm2。
英文摘要	Dissolved organic carbon (DOC）is an important component in the solutions in terrestrial and aquatic ecosystems through its influence on nutrient availability, toxicity, and transport of metals and contaminants. Soluble organic matter in soils plays a key role in the biogeochemistry of carbon and transportation of contaminants. However, limited information is available not only about the roles of leaching on DOC from sloped land in agro-ecosystems, but also about its environmental effects of their losses. Purple soils have a serious soil erosion problem, leading to soil organic matter loss through sediment and in runoff, may result in low content of DOC, which maybe affect the process of nutrient cycling and the productivity of cropland. However, DOC leaching process and fluxes from sloped cropland are rarely independently measured or quantified. Therefore, it is necessary to study the DOC adsorption-desorption and leaching characteristics to provide a scientific basis for elucidating the cycling and transformation of soil organic carbon (SOC) and assessing the risk of contamination from purple soils in hilly area of central Sichuan Basin. The study site is located at Yanting Agro-ecological Station of purple soil, Chinese Academy of Science under Chinese Ecosystem Research Network (CERN). In this study, based on the field investigation and field plot experiment, effects of management measures on DOC contents and distribution, and DOC adsorption- desorption characteristics, DOC leaching process and flux were studied. The main results were summarized as follows: (1) The land use types affect the DOC content of purple soils significantly in the central Sichuan Basin. The order of DOC content in all land use types follow the series vegetable>orchard>paddy>forest>cropland. Significant positive correlation was found between the DOC concentrations in soil and the concentrations of organic carbon, total nitrogen and clay fractions. (2) Adsorption capacities of DOC were different from soils, with the following order: acidic purple soils> neutral purple soils>calcareous purple soils. The DOC sorption amount of the soils was siginificantly and positively correlated with the content of active iron and aluminum oxides and clay fractions, but negatively correlated with pH value. The kinetics of DOC adsorption in the soils can be divided into the two stages, fast (first 0.5 h) and slow reactions (after 4-6 h). The DOC desorption ratioes were positively correlated with the content of calcium carbonate and pH value of soils, but negatively correlated with the content of active iron and aluminum oxides and clay fractions. The DOC desorption percent of calcareous purple soils was higher than that of other purple soils. The DOC adsorption characteristics of soils were significantly influenced by environmental factors (e.g. temperature) and exogenous factors (e.g. ferrous sulfate and phosphate). Temperature also had a strong effect on the adsorption of DOC. With increasing temperature, the adsorption affinity of DOC was gradually decreased, and the initial net release of DOC from the soil samples strongly increased. Phosphorus in solution prevented the adsorption of DOC, whereas ferrous sulfate increased the DOC adsorption. After the soils were treated by H2O2 (deprived organic matter partially), DOC adsorption amounts increased significantly. (3) Rainfall is the main driving force of DOC leaching by forming runoff from the slope cropland in purple soil. Interflow flux was abundant accounted for 72.4% of total runoff (overland flow and interflow) in the sloped cropland (with slope degree of 6.5°) in this region. The DOC leaching flux through interflow from sloped cropland is 7.08 kg/hm2.a, whereas, DOC loss flux through surface runoff is only 1.33 kg/hm2.a. DOC leaching through interflow is the main approach of DOC loss through runoff from sloped cropland of purple soil. (4) The significant linear correlation between DOC leaching flux and rainfall amount is observed. DOC leaching increased with the decrease of soil layer in sloped cropland of purple soil. (5) In different fertilization systems, the contents of DOC with synthetic nitrogen, phosphorus and potassium (NPK) fertilizers plus organic manure (OMNPK) or crop straw debris (RSDNPK) was significant higher than other treatments. With the rising of temperature, the content of DOC increased gradually, and reached its highest levels at the time when the maize was in stamen stage.
语种	中文
公开日期	2013-01-29
内容类型	学位论文
源URL	[http://192.168.143.20:8080/handle/131551/4853]
专题	成都山地灾害与环境研究所_山地表生过程与生态调控重点实验室
推荐引用方式 GB/T 7714	李太魁. 紫色土坡耕地可溶性有机碳迁移过程研究[D]. 北京. 中国科学院研究生院. 2011.

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