Pedoclimatic factors and management determine soil organic carbon and aggregation in farmer fields at a regional scale

Soil organic carbon content has a significant impact on soil fertility and grain yield, making it an important factor affecting agricultural production and food security. Dry farmland, the main type of cropland in China, has a lower soil organic carbon content than that of paddy soil, and it may have a significant carbon sequestration potential. Therefore, in this study we applied the CENTURY model to explore the temporal and spatial changes of soil organic carbon (SOC) in Jilin Province from 1985 to 2015. Dry farmland soil polygons were extracted from soil and land use layers (at the 1:1,000,000 scale). Spatial overlay analysis was also used to extract 1282 soil polygons from dry farmland. Modelled results for SOC dynamics in the dry farmland, in conjunction with those from the Yushu field-validation site, indicated a good level of performance. From 1985 to 2015, soil organic carbon density (SOCD) of dry farmland decreased from 34.36 Mg C ha−1 to 33.50 Mg C ha−1 in general, having a rate of deterioration of 0.03 Mg C ha−1 per year. Also, SOC loss was 4.89 Tg from dry farmland soils in the province, with a deterioration rate of 0.16 Tg C per year. 35.96% of the dry farmland its SOCD increased but 64.04% of the area released carbon. Moreover, SOC dynamics recorded significant differences between different soil groups. The method of coupling the CENTURY model with a detailed soil database can simulate temporal and spatial variations of SOC at a regional scale, and it can be used as a precise simulation method for dry farmland SOC dynamics.

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On the rebound: soil organic carbon stocks can bounce back to near forest levels when agroforests replace agriculture in southern India

SOIL Discussions ◽

10.5194/soild-2-871-2015 ◽

2015 ◽

Vol 2 (2) ◽

pp. 871-902 ◽

Cited By ~ 3

Author(s):

H. C. Hombegowda ◽

O. van Straaten ◽

M. Köhler ◽

D. Hölscher

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Tree Species ◽

Regional Scale ◽

Clay Fraction ◽

Carbon Stocks ◽

Southern India ◽

Reference Plot ◽

Soc Stock ◽

Soc Stocks

Abstract. Tropical agroforestry has an enormous potential to sequester carbon while simultaneously producing agricultural yields and tree products. The amount of soil organic carbon (SOC) sequestered is however influenced by the type of the agroforestry system established, the soil and climatic conditions and management. In this regional scale study, we utilized a chronosequence approach to investigate how SOC stocks changed when the original forests are converted to agriculture, and then subsequently to four different agroforestry systems (AFSs): homegarden, coffee, coconut and mango. In total we established 224 plots in 56 plot clusters across four climate zones in southern India. Each plot cluster consisted of four plots: a natural forest reference plot, an agriculture reference and two of the same AFS types of two ages (30–60 years and > 60 years). The conversion of forest to agriculture resulted in a large loss the original SOC stock (50–61 %) in the top meter of soil depending on the climate zone. The establishment of homegarden and coffee AFSs on agriculture land caused SOC stocks to rebound to near forest levels, while in mango and coconut AFSs the SOC stock increased only slightly above the agriculture stock. The most important variable regulating SOC stocks and its changes was tree basal area, possibly indicative of organic matter inputs. Furthermore, climatic variables such as temperature and precipitation, and soil variables such as clay fraction and soil pH were likewise all important regulators of SOC and SOC stock changes. Lastly, we found a strong correlation between tree species diversity in homegarden and coffee AFSs and SOC stocks, highlighting possibilities to increase carbon stocks by proper tree species assemblies.

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Potential soil organic carbon stock and its uncertainty under various cropping systems in Australian cropland

Soil Research ◽

10.1071/sr13294 ◽

2014 ◽

Vol 52 (5) ◽

pp. 463 ◽

Cited By ~ 18

Author(s):

Zhongkui Luo ◽

Enli Wang ◽

Jeff Baldock ◽

Hongtao Xing

Keyword(s):

Monte Carlo ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Cropping Systems ◽

Regional Scale ◽

Cropping System ◽

Soil Conditions ◽

Sequestration Potential ◽

Soc Stock ◽

Soc Stocks

The diversity of cropping systems and its variation could lead to great uncertainty in the estimation of soil organic carbon (SOC) stock across time and space. Using the pre-validated Agricultural Production Systems Simulator, we simulated the long-term (1022 years) SOC dynamics in the top 0.3 m of soil at 613 reference sites under 59 representative cropping systems across Australia’s cereal-growing regions. The point simulation results were upscaled to the entire cereal-growing region using a Monte Carlo approach to quantify the spatial pattern of SOC stock and its uncertainty caused by cropping system and environment. The predicted potential SOC stocks at equilibrium state ranged from 10 to 140 t ha–1, with the majority in a range 30–70 t ha–1, averaged across all the representative cropping systems. Cropping system accounted for ~10% of the total variance in predicted SOC stocks. The type of cropping system that determined the carbon input into soil had significant effects on SOC sequestration potential. On average, the potential SOC stock in the top 0.3 m of soil was 30, 50 and 60 t ha–1 under low-, medium- and high-input cropping systems in terms of carbon input, corresponding to –2, 18 and 26 t ha–1 of SOC change. Across the entire region, the Monte Carlo simulations showed that the potential SOC stock was 51 t ha–1, with a 95% confidence interval ranging from 38 to 64 t ha–1 under the identified representative cropping systems. Overall, predicted SOC stock could increase by 0.99 Pg in Australian cropland under the identified representative cropping systems with optimal management. Uncertainty varied depending on cropping system, climate and soil conditions. Detailed information on cropping system and soil and climate characteristics is needed to obtain reliable estimates of potential SOC stock at regional scale, particularly in cooler and/or wetter regions.

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Soil organic carbon dynamics at the regional scale as influenced by land use history: a case study in forest soils from southern Belgium

Soil Use and Management ◽

10.1111/j.1475-2743.2007.00135.x ◽

2008 ◽

Vol 24 (1) ◽

pp. 69-79 ◽

Cited By ~ 27

Author(s):

A. Stevens ◽

B. van Wesemael

Keyword(s):

Land Use ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Forest Soils ◽

Regional Scale ◽

Carbon Dynamics ◽

Land Use History ◽

Soil Organic Carbon Dynamics

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A multiple regression approach to assess the spatial distribution of Soil Organic Carbon (SOC) at the regional scale (Flanders, Belgium)

Geoderma ◽

10.1016/j.geoderma.2007.08.025 ◽

2008 ◽

Vol 143 (1-2) ◽

pp. 1-13 ◽

Cited By ~ 176

Author(s):

J. Meersmans ◽

F. De Ridder ◽

F. Canters ◽

S. De Baets ◽

M. Van Molle

Keyword(s):

Spatial Distribution ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Multiple Regression ◽

Regional Scale ◽

Regression Approach

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Soil organic carbon along an altitudinal gradient in the Despeñaperros nature reserve, Southern Spain

Solid Earth Discussions ◽

10.5194/sed-6-2495-2014 ◽

2014 ◽

Vol 6 (2) ◽

pp. 2495-2521

Author(s):

L. Parras-Alcántara ◽

B. Lozano-García ◽

A. Galán-Espejo

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Altitudinal Gradient ◽

Nature Reserve ◽

Regional Scale ◽

C Sequestration ◽

Organic Carbon Content ◽

Soil System ◽

Disturbed Soil ◽

C Cycle

Abstract. Soil organic carbon (SOC) is extremely important in the global carbon (C) cycle as C sequestration in non-disturbed soil ecosystems can be a sink of C and mitigate greenhouse gas driven climate change. Soil organic carbon changes in space and time are relevant to understand the soil system and its role in the C cycle, and this is why the influence of topographic position on SOC should be studied. Seven topographic positions (toposequence) were analyzed along an altitudinal gradient between 607 and 1168 m.a.s.l. in the Despeñaperros nature reserve (Natural Park). At each study site, soil control sections (25 cm intervals) were sampled. The studied soils are mineral soils with > 3% organic carbon content. The main characteristic of the studied soils is SOC reduction with depth; these results were related to the gravel content and to the bulk density. The SOC on the surface was highly variable along the altitudinal gradient ranging between 27.3 and 39.9 g kg−1. The SOC stock (SOCS) in the studied area was influenced by the altitude, varying between 53.8 and 158.0 Mg ha−1. Therefore, the altitude factor must be considered in the SOCS estimation at local-regional scale.

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