Relationship between Soil Organic Carbon Stocks and Clay Content under Different Climatic Conditions in Central China

Zekun Zhong,Guangxin Ren,Chengjie Ren,Yongzhong Feng,Gaihe Yang,Xinhui Han,Yadong Xu,Zhengxing Chen

doi:10.3390/f9100598

Zekun Zhong, Guangxin Ren + Show 6 more

Open Access

https://doi.org/10.3390/f9100598

Copy DOI

Journal: Forests	Publication Date: Sep 26, 2018
Citations: 64	License type: CC BY 4.0

Affiliation: North West Agriculture and Forestry University

Abstract

Understanding the association between soil organic carbon (SOC) and texture under different climatic conditions is important for assessing the effects of future climate changes on SOC stocks. In this study, we conducted a climatic gradient experiment covering three climate types (humid, sub-humid, and semi-arid) with a steep rainfall ranging from 345 to 910 mm, and specifically determined SOC dynamics, clay content, and vegetation and soil characteristics. The results showed that, from semi-arid to humid regions, SOC stocks, SOC, and clay content increased synchronously and were closely related in layers of depths of both 0–10 and 10–20 cm. In contrast, under similar climatic conditions, SOC dynamics were mainly affected by vegetation and soil characteristics, especially total nitrogen and total phosphorus dynamics, but not the soil clay content. Therefore, these results suggest that the relationship between SOC stocks and clay content depended on scale sizes. Specifically, on a larger scale with different climatic gradients, the climate may partly determine the changes in SOC and clay dynamics, whereas, at a smaller scale where climate type does not vary considerably, the changes in SOC stocks and clay content may be related to vegetation diversity and soil nutrient dynamics. These results may contribute to future model development and the projection of changes in soil carbon storage.

Highlights

Soil organic carbon (SOC) is the largest constituent of the Earth’s terrestrial carbon pool [1], and slight C losses from the soil may lead to considerable changes in atmospheric CO2 concentration [2], which would affect the magnitude of future climate change [3]
Relationship between Clay and SOC Depended on Precipitation in Different Climate Types
Our study showed that SOC stock and clay percentage decreased linearly from humid climatic conditions to the semi-arid sites, suggesting that these changes were partly controlled by rainfall regimes at a regional scale

Summary

Introduction

Soil organic carbon (SOC) is the largest constituent of the Earth’s terrestrial carbon pool [1], and slight C losses from the soil may lead to considerable changes in atmospheric CO2 concentration [2], which would affect the magnitude of future climate change [3]. Numerous studies [4,5,6] have reported SOC dynamics, in the efforts to physically protect organic C. Jagadamma and Lal [7] concluded that the clay fraction in the soil accumulated more SOC than other fractions from several long-term agricultural management practice studies. Based on data from several short-term litter decomposition studies, Giardina [8] reported a decline in SOC decomposition rates with increasing clay content. Few studies have assessed the scaling properties of the relationships between SOC stocks and clay content under different climate types, which is indispensable for accurate future predictions of changes in terrestrial C sources and sinks. In response to diverse rainfall regimes, the interactions between SOC stocks and clay content may have different responses and outcomes [9].

Methods

Results

Discussion

Conclusion