Response of soil organic carbon to vegetation restoration in different erosion environments in the hilly-gullied region of the Loess Plateau

ABSTRACT&#160;Redistribution of soil organic carbon (SOC) in response to soil erosion along slopes plays an important role in understanding the mechanisms of SOC&#8217;s spatial distribution and turnover. Consequently, SOC redistribution has been considered in many&#160;conceptual&#160;or mathematical models of soil carbon stability and storage.&#160;Vegetation restoration has been identified as an effective method to alleviate soil erosion on the Loess Plateau, however, little research has addressed vegetation restoration&#8217;s effect on the SOC redistribution processes, particularly SOC&#8217;s spatial distribution and stability. This study quantified the SOC stock and pool distribution on slopes along geomorphic gradients in naturally regenerating forests (NF) and an artificial black locust plantation (BP), and used a corn field as a control (CK). The following results were as follows: (1) Vegetation restoration, particularly NF, slowed the migration of SOC and reduced the heterogeneity of its distribution effectively. The topsoil SOC ratios of the sedimentary area to the stable area were 109%, 143%, and 210% for NF, the BP and CK, respectively; (2) Vegetation restoration decreased the loss of labile organic carbon by alleviating the loss of dissolved organic carbon (DOC) and easily oxidized organic carbon (EOC). The DOC/SOC in the BP and NF increased significantly, and were 13.14 and 17.57 times higher, respectively, than in the CK (p < 0.05), while the EOC/SOC in the BP and NF was slightly higher than in the CK. (3) A relevant schematic diagram of SOC cycle patterns and redistribution along the Loess slope was drawn under vegetation restoration. These results suggest that vegetation restoration in the Loess slope effectively alleviated the redistribution and spatial heterogeneity of SOC through reducing soil erosion. Thus, the effects of vegetation restoration on SOC redistribution should be pay more attention in regional carbon storage estimation, especially in the Loess gully regions.Keywords: Vegetation Restoration, Soil Organic Carbon Redistribution, Loess Slope, Soil Erosion, Soil Organic Carbon Stability

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Soil organic carbon distribution in relation to land use and its storage in a small watershed of the Loess Plateau, China

CATENA ◽

10.1016/j.catena.2011.07.012 ◽

2012 ◽

Vol 88 (1) ◽

pp. 6-13 ◽

Cited By ~ 91

Author(s):

Xuan Fang ◽

Zhijing Xue ◽

Bicheng Li ◽

Shaoshan An

Keyword(s):

Land Use ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Loess Plateau ◽

Small Watershed ◽

Carbon Distribution ◽

The Loess Plateau

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Soil organic carbon dynamics following afforestation in the Loess Plateau of China

Biogeosciences Discussions ◽

10.5194/bgd-10-11181-2013 ◽

2013 ◽

Vol 10 (7) ◽

pp. 11181-11211 ◽

Cited By ~ 5

Author(s):

N. Lu ◽

J. Liski ◽

R. Y. Chang ◽

A. Akujärvi ◽

X. Wu ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Loess Plateau ◽

Carbon Fixation ◽

Temporal Dynamics ◽

Climatic Factors ◽

Early Stage ◽

Arable Land ◽

The Loess Plateau ◽

Successional Stage

Abstract. Soil organic carbon (SOC) is the largest terrestrial carbon pool and sensitive to land use and cover change; its dynamics is critical for carbon cycling in terrestrial ecosystems and the atmosphere. In this study, we combined a modeling approach and field measurements to examine the temporal dynamics of SOC following afforestation of former arable land at six sites under different climatic conditions in the Loess Plateau during 1980–2010. The results showed that the measured mean SOC increased to levels higher than before afforestation when taking the last measurements (i.e., at age 25 to 30 yr), although it decreased in the first few years at the wetter sites. The accumulation rates of SOC were 1.58 to 6.22% yr–1 in the upper 20 cm and 1.62 to 5.15% yr–1 in the upper 40 cm of soil. The simulations reproduced the basic characteristics of measured SOC dynamics, suggesting that litter input and climatic factors (temperature and precipitation) were the major causes for SOC dynamics and the differences among the sites. They explained 88–96, 48–86 and 57–74% of the variations in annual SOC changes at the soil depths of 0–20, 0–40, and 0–100 cm, respectively. Notably, the simulated SOC decreased during the first few years at all the sites, although the magnitudes of decreases were small at the drier sites. This suggested that the modeling may be advantageous in capturing SOC changes at finer time scale. The discrepancy between the simulation and measurement was a result of uncertainties in model structure, data input, and sampling design. Our findings indicated that afforestation promoted soil carbon sequestration at the study sites, which is favorable for further restoration of the vegetation and environment. Afforestation activities should decrease soil disturbances to reduce carbon release in the early stage. The long-term strategy for carbon fixation capability of the plantations should also consider the climate and site conditions, species adaptability, and successional stage of recovery.

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