Vegetation restoration alleviated the soil surface organic carbon redistribution in the hillslope scale on the Loess Plateau, China

Author(s):  
Yipeng Liang ◽  
Tonggang Zha ◽  
Xiang Li ◽  
Xiaoxia Zhang

<p><strong>ABSTRACT</strong> </p><p>Redistribution of soil organic carbon (SOC) in response to soil erosion along slopes plays an important role in understanding the mechanisms of SOC’s spatial distribution and turnover. Consequently, SOC redistribution has been considered in many conceptual or mathematical models of soil carbon stability and storage. Vegetation restoration has been identified as an effective method to alleviate soil erosion on the Loess Plateau, however, little research has addressed vegetation restoration’s effect on the SOC redistribution processes, particularly SOC’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.</p><p>Keywords: Vegetation Restoration, Soil Organic Carbon Redistribution, Loess Slope, Soil Erosion, Soil Organic Carbon Stability</p>

2021 ◽  
Vol 8 ◽  
Author(s):  
Yipeng Liang ◽  
Xiang Li ◽  
Tonggang Zha ◽  
Xiaoxia Zhang

The redistribution of soil organic carbon (SOC) in response to soil erosion along the loess slope, China, plays an important role in understanding the mechanisms that underlie SOC’s spatial distribution and turnover. Consequently, SOC redistribution is key to understanding the global carbon cycle. Vegetation restoration has been identified as an effective method to alleviate soil erosion on the Loess Plateau; however, little research has addressed vegetation restoration’s effect on the SOC redistribution processes, particularly SOC’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 obtained: 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, BP, and CK, respectively; 2) during migration, 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 was 13.14 and 17.57 times higher, respectively, than that in the CK (p < 0.05), while the EOC/SOC in the BP and NF was slightly higher than that in the CK. A relevant schematic diagram of SOC cycle patterns and redistribution along the loess slope was drawn under vegetation restoration. The results suggest that vegetation restoration in the loess slope, NF in particular, is an effective means to alleviate the redistribution and spatial heterogeneity of SOC and reduce soil erosion.


2020 ◽  
Author(s):  
Xiaoxia Zhang ◽  
Xiang Li ◽  
Yipeng Liang ◽  
Tonggang Zha

<p>Soil organic carbon (SOC) redistribution along the Loess slope under the effect of soil erosion plays an important role in understanding mechanism of SOC spatial distribution and turnover, hence to its effects on global carbon cycle. Vegetation restoration has been taken as an effective method to alleviate soil erosion on the Loess Plateau, while little research focused on the impact of vegetation restoration on the redistribution processes, especially the spatial distribution and stability of SOC. Here, we quantified the SOC stock and pool distribution on the loess slopes along geomorphic gradients under naturally regenerating forests (NF) and artificial black locust plantation (BP), using corn field as a control (CK).The results were as follows:  (1) vegetation restoration, especially NF, effectively slowed down the migration of SOC resulting from soil erosion and reduced the heterogeneity of SOC distribution. The ratios of topsoil SOC in the sedimentary area to the stable area were 109%, 143%, and 210% under the NF, BP, and CK, respectively. And (2) Vegetation restoration reduced the loss of labile organic carbon by alleviating the loss of dissolved organic carbon (DOC) and easily oxidized organic carbon (EOC) during migration. Both DOC/SOC and EOC/SOC ratios under NF and BP presented far less differences between the sedimentary and erosion zones than CK.A schematic diagram of SOC cycle patterns and redistribution along the loess slope under vegetation restoration based on our findings and discussions. The results suggested that vegetation restoration in the Loess slope, NF in particular, was an effective means for alleviating the redistribution and spatial heterogeneity of SOC and reducing soil erosion. Information from this study is useful for understanding the carbon cycles in restored ecosystems and evaluating the ecosystem services of natural and managed forests in soil erosion control and carbon sequestration.</p>


2020 ◽  
Author(s):  
Peng Shi ◽  
Yan Zhang ◽  
Kexin Lu ◽  
Zhaohong Feng ◽  
Yang Yu

<p>Vegetation restoration, terrace and check dam construction are the major measures for soil and water conservation on the Loess Plateau. These effective measures of stabilizing soils have significant impacts on soil organic carbon (SOC) distribution. To understand the impact of land-use changes combined with check dam construction on SOC distribution, 1060 soil samples were collected across a watershed on the Loess Plateau. Forestland, shrubland and terrace had significant higher SOC concentrations in the 0-20 cm soil layer than that of sloping cropland.    Land use change affects the process of runoff and sediment transportation, which has an impact on the migration and transformation of soil carbon. The soil erosion of sloping farmland is the most serious, and the maximum annual erosion rate is as high as 10853.56 t·km<sup>-2</sup>. Carbon sedimented in the dam land was mainly from sloping cropland, and this source percentage was 65%. The application of hydrological controls to hillslopes and along river channels should be considered when assessing carbon sequestration within the soil erosion subsystem. </p>


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1438
Author(s):  
Snežana Jakšić ◽  
Jordana Ninkov ◽  
Stanko Milić ◽  
Jovica Vasin ◽  
Milorad Živanov ◽  
...  

Spatial distribution of soil organic carbon (SOC) is the result of a combination of various factors related to both the natural environment and anthropogenic activities. The aim of this study was to examine (i) the state of SOC in topsoil and subsoil of vineyards compared to the nearest forest, (ii) the influence of soil management on SOC, (iii) the variation in SOC content with topographic position, (iv) the intensity of soil erosion in order to estimate the leaching of SOC from upper to lower topographic positions, and (v) the significance of SOC for the reduction of soil’s susceptibility to compaction. The study area was the vineyard region of Niš, which represents a medium-sized vineyard region in Serbia. About 32% of the total land area is affected, to some degree, by soil erosion. However, according to the mean annual soil loss rate, the total area is classified as having tolerable erosion risk. Land use was shown to be an important factor that controls SOC content. The vineyards contained less SOC than forest land. The SOC content was affected by topographic position. The interactive effect of topographic position and land use on SOC was significant. The SOC of forest land was significantly higher at the upper position than at the middle and lower positions. Spatial distribution of organic carbon in vineyards was not influenced by altitude, but occurred as a consequence of different soil management practices. The deep tillage at 60–80 cm, along with application of organic amendments, showed the potential to preserve SOC in the subsoil and prevent carbon loss from the surface layer. Penetrometric resistance values indicated optimum soil compaction in the surface layer of the soil, while low permeability was observed in deeper layers. Increases in SOC content reduce soil compaction and thus the risk of erosion and landslides. Knowledge of soil carbon distribution as a function of topographic position, land use and soil management is important for sustainable production and climate change mitigation.


Author(s):  
Hui Wei ◽  
Wenwu Zhao ◽  
Han Wang

Large-scale vegetation restoration greatly changed the soil erosion environment in the Loess Plateau since the implementation of the “Grain for Green Project” (GGP) in 1999. Evaluating the effects of vegetation restoration on soil erosion is significant to local soil and water conservation and vegetation construction. Taking the Ansai Watershed as the case area, this study calculated the soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration, using the Chinese Soil Loess Equation (CSLE), based on rainfall and soil data, remote sensing images and socio-economic data. The effect of vegetation restoration on soil erosion was evaluated by comparing the average annual soil erosion modulus under two scenarios among 16 years. The results showed: (1) vegetation restoration significantly changed the local land use, characterized by the conversion of farmland to grassland, arboreal land, and shrub land. From 2000 to 2015, the area of arboreal land, shrub land, and grassland increased from 19.46 km2, 19.43 km2, and 719.49 km2 to 99.26 km2, 75.97 km2, and 1084.24 km2; while the farmland area decreased from 547.90 km2 to 34.35 km2; (2) the average annual soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration was 114.44 t/(hm²·a) and 78.42 t/(hm²·a), respectively, with an average annual reduction of 4.81 × 106 t of soil erosion amount thanks to the vegetation restoration; (3) the dominant soil erosion intensity changed from “severe and light erosion” to “moderate and light erosion”, vegetation restoration greatly improved the soil erosion environment in the study area; (4) areas with increased erosion and decreased erosion were alternately distributed, accounting for 48% and 52% of the total land area, and mainly distributed in the northwest and southeast of the watershed, respectively. Irrational land use changes in local areas (such as the conversion of farmland and grassland into construction land, etc.) and the ineffective implementation of vegetation restoration are the main reasons leading to the existence of areas with increased erosion.


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