| 亚热带稻田土壤碳氮磷生态化学计量学特征 |
| 摘要点击 1742 全文点击 706 投稿时间：2019-06-22 修订日期：2019-07-30 |
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| 中文关键词 计量土壤学 土壤养分 底土 土壤剖面 土壤发生分类 土壤环境因子 |
| 英文关键词 pedometrics soil nutrients subsoil soil profile soil classification soil-environmental factor |
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| 中文摘要 |
| 为了解稻田土壤中是否存在稳定的土壤有机碳（C）、氮（N）和磷（P）比值，基于亚热带区110个水稻土剖面和587个发生层的土壤调查数据库，在区域尺度上分析了典型水稻土C：N：P比值的生态化学计量学特征，并应用相关分析和冗余分析，研究水稻土C：N：P比值与土壤-环境因子（地形和母质、土壤发生层、土壤类型和土壤理化性质）的关系.结果显示，亚热带区稻田土壤C：N、C：P和N：P的剖面加权平均值分别为12.6、49和3.9，C：N：P为38：3.2：1.不同母质起源、不同土壤亚类和不同发生层的水稻土C：N变异相对较小；但C：P和N：P的变异很大，两者均值也远低于全球（186和13.1）和中国土壤（136和9.3）的C：P和N：P的平均水平.尽管稻田土壤剖面的C：N：P相对不稳定，但由于稻田表土生物与环境相互作用强烈，表土C：N相对稳定（14.2）.这反映长期水耕熟化作用下，稻田表土中C和N仍存在紧密的耦合作用.然而，在稻田土壤剖面上，C：P和N：P并不稳定，SOC与全P含量、全N与全P含量也无显著相关性，表明环境变化可能导致土壤C：N：P解耦.地形、土壤质地、氧化铁和容重是调控稻田土壤剖面C：N：P的关键土壤环境因子. |
| 英文摘要 |
| This study aims to understand the existence of stable soil organic carbon (C), nitrogen (N), and phosphorus (P) ratios in paddy soil. Based on a field soil survey database, the ecological stoichiometry of the C:N:P ratio of 110 subtropical paddy soil profiles and 587 genetic horizons were analyzed at a regional scale. Relevant analysis and redundancy analysis (RDA) are used to study the relationships between C:N:P ratios and soil-environmental factors (topography, parent materials, soil genetic horizons, soil groups, soil physical, and chemical properties). The results showed that the weighted averages of C:N, C:P, and N:P in paddy soils of subtropical regions were 12.6, 49, and 3.9, respectively, and C:N:P was 38:3.2:1. The C:N of paddy soil did not vary significantly with parent materials, soil groups, or genetic horizons. However, the C:P and N:P variations were significantly different, and the mean values of the two were much lower than global ratios (186 and 13.1) and average levels of C:P and N:P in Chinese soils (136 and 9.3). Although the C:N:P ratio in the paddy soil profile was relatively unstable, the topsoil C:N (14.2) was relatively stable due to the strong interaction between the topsoil and the environment. This reflects the close coupling of C and N in the topsoil of paddy fields under long-term anthrostagnic maturation. However, in the paddy soil profile, C:P and N:P were not stable, and there was no significant correlation between soil organic carbon (SOC) and total P content, total N, or total P content, which suggests that environmental changes may lead to soil C:N:P decoupling. It was found that topography, soil texture, iron oxide, and bulk density are all key soil-environmental factors that regulate the soil profile of rice paddy C:N:P. |
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