Effective soil erosion control represents a significant net carbon sequestration

Lishan Ran,Xiankun Yang,Xixi Lu,Nufang Fang

doi:10.1038/s41598-018-30497-4

Abstract

The debate over whether soil erosion is a carbon (C) sink or atmospheric CO2 source remains highly controversial. For the first time, we report the magnitude of C stabilization associated with soil erosion control for an entire large river basin. The soil erosion of the Yellow River basin in northern China is among the most severe worldwide. Progressive soil conservation has been implemented by the Chinese government since the 1970s, including the largest ever revegetation programme, the Grain-for-Green Project, which began in 1999. Based on compiled hydrological records and organic carbon (OC) data, together with primary production estimates, we evaluated the sequestered OC resulting from soil conservation. Compared with that at baseline in 1950–1970, in which significant soil conservation did not occur, the fate of erosion-induced OC was substantially altered in the period from 2000–2015. Approximately 20.6 Tg of OC were effectively controlled per year by soil conservation efforts. Simultaneously, the decomposition of erosion-induced soil organic carbon (SOC) declined from 8 Tg C yr−1 to current 5.3 Tg C yr−1. The reduced C emissions (2.7 Tg C yr−1) within the Yellow River basin alone account for 12.7% of the mean C accumulation acquired via forest expansion throughout all of China previously assessed. If the accumulated C in restored plants and soils was included, then 9.7 Tg C yr−1 was reduced from the atmospheric C pool during this period, which represents a tremendous C-capturing benefit. Thus, the increased C storage obtained via soil conservation should be considered in future C inventories.

Highlights

Soil erosion is one of the most challenging environmental problems facing human society, and it has garnered widespread attention worldwide because of the associated land degradation, which is closely correlated with human livelihoods[1,2,3]
We first examined the temporal trends in annual net primary production (NPP) (Supplementary), which exhibited a steady increase over the period 2000–2015 despite inter-annual variability and considerable uncertainty associated with annual estimations (Fig. 2)
Because human-induced C control is based on a budgetary analysis, its significance and accuracy in modifying the basin-scale organic carbon (OC) cycle relies on the amount of eroded soil organic carbon (SOC)

Summary

Introduction

Soil erosion is one of the most challenging environmental problems facing human society, and it has garnered widespread attention worldwide because of the associated land degradation, which is closely correlated with human livelihoods[1,2,3]. The recent renewed awareness of the global significance of soil erosion and conservation in climate change mitigation has further illustrated the urgency of performing systematic investigations into SOC dynamics[11,12]. Shrub, and grass species adaptable to the local arid climate have been planted on former croplands Both the soil erosion rate and sediment flux have been substantially reduced (Fig. 1), and the delivery of ecosystem services has been improved [15,16]. We investigated human-induced C capture by comparing the organic carbon (OC) budget of two scenarios: a baseline from 1950–1970 before the implementation of large-scale soil conservation practices and a scenario from 2000–2015 after the introduction of the Grain-for-Green Project (Methods)

Objectives

Methods

Results

Conclusion