Scholarlink

Background and aims <p>Highly weathered tropical forests are widely recognised as nitrogen (N)-rich and phosphorus (P)-poor. The input of nutrients affects soil carbon (C) cycling and storage in these ecosystems. Short-term nutrient addition may promote soil organic C (SOC) accumulation both directly, by altering topsoil carbon pools, and indirectly, by enhancing microbial C use efficiency (CUE) to facilitate carbon conversion and stabilization processes. In tropical forests characterized by high temperatures and humidity, where material turnover is rapid, acidic phosphorus-deficient soils show heightened responsiveness to nutrient inputs. These additions quickly stimulate SOC accumulation and transformation processes, particularly evident in short-term dynamics. However, the effects of short-term nutrient addition on the soil C accumulation process remain unclear. This study aimed to clarify the mechanisms of SOC responses to short-term nutrient addition.</p> Methods <p>A one-year N and P addition experiment in the tropical forest of Hainan, China, was performed. The SOC, soil C fractions (particulate organic C [POC] and mineral-associated organic C [MAOC]), microbial biomass, enzyme activity, and physicochemical properties at depths of 0–10, 10–20 and 20–40&#xa0;cm were measured.</p> Results <p>Short-term nutrient addition increased SOC (8.91–20.03%), POC (6.65–24.90%) and MAOC (8.74–19.89%) in the topsoil (0–10&#xa0;cm and 10–20&#xa0;cm), whereas no significant changes occurred in the subsoil (20–40&#xa0;cm). Pearson’s correlation analysis revealed that litter biomass and CUE were significantly positively correlated with SOC. The random forest model revealed POX and N acquisition enzymes (NAG + LAP) as main drivers of POC, whereas for MAOC, POX and N availability (NH<sub>4</sub><sup>+</sup>-N and NO<sub>3</sub><sup>–</sup>-N) were the dominant factors. In addition, POX, N availability and the C:P ratio were the dominant regulators of SOC accumulation, which exerted their influence through both direct and indirect pathways. The partial least squares–path model showed that short-term nutrient addition influenced SOC by altering soil physicochemical properties (i.e., pH and available phosphorus) and microbial characteristics (microbial biomass and enzyme activity).</p> Conclusions <p>These results suggest that short-term nutrient addition increased SOC by improving physicochemical properties and decreasing microbial activity (POX and MBC). This could provide insight to understanding the effects of nutrient addition on the SOC pool in tropical forests.&#xa0;</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Short-term nutrient addition increases soil organic carbon accumulation in tropical forest

  • 期刊论文

  • 发表日期：

    2025年5月31日

查看全文
  • Tianyan Su,
  • Yamin Jiang,
  • Huaying Chen,
  • Ying Wang,
  • Qiu Yang,
  • Jialing Li,
  • Jing-li Lu,
  • Hongyu Ran,
  • Huai Yang,
  • Wenjie Liu,
  • Mengyang Fang,
  • Lianghong Huang

摘要

Background and aims

Highly weathered tropical forests are widely recognised as nitrogen (N)-rich and phosphorus (P)-poor. The input of nutrients affects soil carbon (C) cycling and storage in these ecosystems. Short-term nutrient addition may promote soil organic C (SOC) accumulation both directly, by altering topsoil carbon pools, and indirectly, by enhancing microbial C use efficiency (CUE) to facilitate carbon conversion and stabilization processes. In tropical forests characterized by high temperatures and humidity, where material turnover is rapid, acidic phosphorus-deficient soils show heightened responsiveness to nutrient inputs. These additions quickly stimulate SOC accumulation and transformation processes, particularly evident in short-term dynamics. However, the effects of short-term nutrient addition on the soil C accumulation process remain unclear. This study aimed to clarify the mechanisms of SOC responses to short-term nutrient addition.

Methods

A one-year N and P addition experiment in the tropical forest of Hainan, China, was performed. The SOC, soil C fractions (particulate organic C [POC] and mineral-associated organic C [MAOC]), microbial biomass, enzyme activity, and physicochemical properties at depths of 0–10, 10–20 and 20–40 cm were measured.

Results

Short-term nutrient addition increased SOC (8.91–20.03%), POC (6.65–24.90%) and MAOC (8.74–19.89%) in the topsoil (0–10 cm and 10–20 cm), whereas no significant changes occurred in the subsoil (20–40 cm). Pearson’s correlation analysis revealed that litter biomass and CUE were significantly positively correlated with SOC. The random forest model revealed POX and N acquisition enzymes (NAG + LAP) as main drivers of POC, whereas for MAOC, POX and N availability (NH4+-N and NO3–-N) were the dominant factors. In addition, POX, N availability and the C:P ratio were the dominant regulators of SOC accumulation, which exerted their influence through both direct and indirect pathways. The partial least squares–path model showed that short-term nutrient addition influenced SOC by altering soil physicochemical properties (i.e., pH and available phosphorus) and microbial characteristics (microbial biomass and enzyme activity).

Conclusions

These results suggest that short-term nutrient addition increased SOC by improving physicochemical properties and decreasing microbial activity (POX and MBC). This could provide insight to understanding the effects of nutrient addition on the SOC pool in tropical forests.