| 四川盆地耕地土壤颗粒态和矿物结合态有机碳含量特征及其影响因素 |
| 摘要点击 2046 全文点击 172 投稿时间：2024-02-01 修订日期：2024-04-13 |
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| 中文关键词 土壤颗粒态有机碳（POC） 矿物结合态有机碳（MAOC） 空间分布 耕地 影响因素 四川盆地 |
| 英文关键词 soil particulate organic carbon（POC） mineral-associated organic carbon（MAOC） spatial distribution cultivated land influencing factors Sichuan Basin |
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| 中文摘要 |
| 揭示区域土壤有机碳组分构成及与各种因素间的关系有助于深刻理解耕地土壤有机碳变化的潜在机制. 以四川盆地871个采样点数据为基础,采用方差分析、相关分析和随机森林模型等方法探究该区域耕地表层土壤颗粒态和矿物结合态有机碳含量特征及其与气候、地形、土壤质地、耕地利用类型以及施肥等因素的关系. 结果表明,四川盆地耕地表层土壤ω（颗粒态有机碳）和ω（矿物结合态有机碳）平均值分别为5.01 g·kg-1和9.79 g·kg-1,分别占土壤总有机碳的32.5%和67.5%；颗粒态有机碳的所占比例随着土壤总有机碳增加而上升. 空间上,土壤有机碳2个组分均呈现“盆地中心低、边缘高”的空间分布格局,由结构性因素和随机性因素共同决定. 随机森林模型分析结果显示,耕地利用类型的重要性远高于其他因素. 净初级生产力（NPP）、年均气温和土壤质地是与旱地土壤有机碳2个组分相关性最大的因素；水旱轮作地上土壤颗粒态有机碳与年均气温和坡度的相关性最大,而矿物结合态有机碳与年均气温和土壤质地的相关性较高；与水田土壤颗粒态和矿物结合态有机碳相关性最大的因素为土壤质地. 上述结果表明,四川盆地耕地表层土壤有机碳以矿物结合态有机碳为主,耕地利用类型是土壤有机碳2个组分的主控因素,其他各因素的作用因耕地利用类型而异. |
| 英文摘要 |
| Exploring the composition of regional soil organic carbon （SOC） components and identifying their influencing factors are of utmost importance to deeply understand the potential mechanisms of SOC change in cropland soil. Based on data from 871 soil sampling points, this study explored the characteristics of soil particulate and mineral-associated organic carbon （POC and MAOC） in the surface soil of cropland and the relationships with climate, terrain, soil texture, agricultural land-use type, and fertilization across the Sichuan basin using analysis of variance, correlation analysis, and a random forest model. The results showed that the average content of POC and MAOC in the surface soil of cropland was 5.01 g·kg-1 and 9.79 g·kg-1, respectively, accounting for 32.5% and 67.5% of the total SOC； the proportion of POC increased with SOC. The two SOC fractions showed a similar spatial distribution pattern, with the content being higher in peripheral areas and lower in the middle of the basin, which were determined together by structural and random factors. The results of the random forest model showed that the relative importance of agricultural land-use type was much more important than other factors. NPP, mean annual temperature, and soil texture showed the largest correlations with the two SOC fractions in dryland； mean annual temperature and slope had larger correlations with POC and mean annual temperature and soil texture in the dryland-paddy rotation land； and soil texture was the most relevant factor to POC and MAOC in the paddy field. The above results suggested that MAOC was the main component of SOC, and agricultural land-use type was the dominant control and regulated the effects of other factors on the two SOC fractions. |
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