不同土地利用方式和气候区域下土壤溶解性有机碳差异特征

Characteristics of dissolved organic carbon under various land use types and climatic regions

  • 摘要: 土壤溶解性有机碳(DOC)是土壤有机碳库的重要组成部分,探讨不同土地利用方式下土壤有机碳(SOC)和DOC含量、DOC分配比例(DOC/SOC)及其差异性特征,对于深刻认识SOC周转及其可持续管理具有重要意义。通过搜集、提取2000—2024年我国已发表的涉及农田、林地和草地3种土地利用方式下表层土壤(0~20 cm)DOC含量的相关数据,共获得116篇目标文献,得到549组匹配数据;定量分析不同气候区和土壤类型条件下,不同土地利用方式(农田、林地和草地)对DOC含量影响及其SOC与DOC的相互关系。结果表明:不同土地利用方式下,SOC和DOC含量差异显著,即林地中SOC和DOC含量均高于草地和农田。不同气候区,3种土地利用方式下DOC与SOC之间均呈现极显著的正相关关系(P<0.01),且DOC分配比例各不相同。亚热带季风性气候区,林地土壤中DOC所占比例的均值为2.30%,显著高于农田(0.87%)和草地(0.66%)(P<0.05);温带季风性气候区,3种土地利用方式下DOC分配比例无显著差异(P>0.05),其中林地(1.27%)>农田(1.18%)>草地(1.03%);温带大陆性气候区,农田、林地和草地土壤中DOC分配比例分别为1.76%、1.43%和1.28%,但无显著差异(P>0.05)。农田中不同类型土壤的DOC分配比例存在显著差异,其中褐土的DOC分配比例最高,均值为1.61%,其次是灰漠土(1.38%)、黑土(1.10%)、红壤(0.99%)和潮土(0.89%),而水稻土最低(0.74%)。研究结果对于揭示不同土地利用方式下的DOC变化具有重要意义,同时为不同土地利用方式下DOC管理提供参考。

     

    Abstract: The soil dissolved organic carbon (DOC) is an important component of soil organic carbon (SOC) pool. Exploring the variations of SOC, DOC contents and the proportions of DOC to SOC under different land use types is of great significance to deeply understand the turnover and sustainable management of SOC. The DOC content data of surface soil (0-20 cm) under the three land use types, including cropland, forestland and grassland, were collected and extracted from published studies conducted in China from 2000 to 2024. A total of 116 target literature were obtained, yielding 549 matched data sets. A quantitative analysis was conducted to determine the impact of different land use types, climate zones and soil types on DOC content under different climate regions and soil types, as well as the relationship between SOC and DOC. The results showed there was a significant difference in the contents of SOC and DOC under the three land use types. The SOC and DOC contents under forestland were higher than those in grassland and cropland. In different climatic regions, there was a significant positive correlation between DOC and SOC under the three land use types (P<0.01), and the proportion of DOC was different. In subtropical monsoon climate region, the mean value of DOC proportion in forestland soil was 2.30%, which was significantly higher than that in cropland (0.87%) and grassland (0.66%, P<0.05); in temperate monsoon climate region, there was no significant difference in DOC proportion (P>0.05) under the three land use types, including forestland (1.27%) > cropland (1.18%) > grassland (1.03%); in temperate continental climate region, DOC proportion in cropland, forestland and grassland soil was 1.76%,1.43% and 1.28%, respectively, but there was no significant difference (P>0.05). The DOC proportion in different soil types of croplands is significantly different. Among them, the DOC proportion in cinnamon soil was the highest, and the mean value was 1.61%, followed by gray desert soil (1.38%), black soil (1.10%), red soil (0.99%) and fluvo-aquic soil (0.89%), while paddy soil was the lowest (0.74%). The research has important implications for revealing DOC changes and providing important theoretical significance for the management of DOC under different land use practices.

     

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