Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of Southwestern China

Abstract. The conversion of natural vegetation to managed ecosystems may negatively influence soil organic carbon (SOC) and total nitrogen (TN) stocks, particularly in the fragile ecosystems. The objective of present study was to assess SOC and TN stocks losses by combining deep sampling with mass-based calculations upon land-use changes in a typical karst area of Southwestern China. We quantified the changes from native forest to grassland, secondary shrub, eucalyptus plantation, sugarcane and corn fields (both defined as croplands), on the SOC and TN stocks down to 100 cm depth using fixed-depth (FD) and equivalent soil mass (ESM) approaches. The results showed that converting forest to cropland and other types significantly led to SOC and TN losses, although the effect magnitude partly depended on both sampling depths and soil mass considered. On average, the shifting from native forest to cropland led to SOC losses by 19.1 %, 25.1 %, 30.6 %, 36.8 % and 37.9 % for the soil depths of 0–10, 0–20, 0–40, 0–60 and 0–100 cm, respectively, which highlighted that shallow sampling underestimated SOC losses. Moreover, the FD method underestimated SOC and TN losses for the upper 40 cm layer, but overestimated the losses in the deeper profiles. We suggest that the ESM together with deep sampling should be encouraged to detect the differences in SOC stocks. In conclusion, the conversion of forest to managed systems, in particular croplands significantly decreased in SOC and TN stocks, although the effect magnitude to some extent depended on sampling depth and calculation approach selected.

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Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of southwestern China

Solid Earth ◽

10.5194/se-7-1075-2016 ◽

2016 ◽

Vol 7 (4) ◽

pp. 1075-1084 ◽

Cited By ~ 7

Author(s):

Yecui Hu ◽

Zhangliu Du ◽

Qibing Wang ◽

Guichun Li

Keyword(s):

Land Use ◽

Land Use Changes ◽

Soil Mass ◽

Karst Area ◽

Southwestern China ◽

Native Forest ◽

Eucalyptus Plantation ◽

Carbon And Nitrogen ◽

Managed Ecosystems ◽

Effect Magnitude

Abstract. The conversion of natural vegetation to human-managed ecosystems, especially the agricultural systems, may decrease soil organic carbon (SOC) and total nitrogen (TN) stocks. The objective of present study was to assess SOC and TN stocks losses by combining deep sampling with mass-based calculations upon land-use changes in a typical karst area of southwestern China. We quantified the changes from native forest to grassland, secondary shrub, eucalyptus plantation, sugarcane and corn fields (both defined as croplands), on the SOC and TN stocks down to 100 cm depth using fixed-depth (FD) and equivalent soil mass (ESM) approaches. The results showed that converting forest to cropland and other types significantly led to SOC and TN losses, but the extent depended on both sampling depths and calculation methods selected (i.e., FD or ESM). On average, the shifting from native forest to cropland led to SOC losses by 19.1, 25.1, 30.6, 36.8 and 37.9 % for the soil depths of 0–10, 0–20, 0–40, 0–60 and 0–100 cm, respectively, which highlighted that shallow sampling underestimated SOC losses. Moreover, the FD method underestimated SOC and TN losses for the upper 40 cm layer, but overestimated the losses in the deeper layers. We suggest that the ESM together with deep sampling should be encouraged to detect the differences in SOC stocks. In conclusion, the conversion of forest to managed systems, in particular croplands significantly decreased in SOC and TN stocks, although the effect magnitude to some extent depended on sampling depth and calculation approach selected.

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Effect of deforestation and subsequent land-use management on soil carbon stocks in the South American Chaco

10.5194/soil-2017-34 ◽

2018 ◽

Author(s):

Natalia Andrea Osinaga ◽

Carina Rosa Álvarez ◽

Miguel Angel Taboada

Keyword(s):

Land Use ◽

Land Use Changes ◽

Warm Season ◽

Native Forest ◽

Continuous Cropping ◽

Organic C ◽

Soil C ◽

C Stocks ◽

Chaco Region ◽

The Impact

Abstract. Abstract. The sub-humid Chaco region of Argentina, originally covered by dry sclerophyll forest, has been subjected to clearing since the end of the '70 and replacement of the forest by no till farming. Land use changes produced a decrease in aboveground carbon stored in forests, but little is known about the impact on soil organic C stocks. The aim of this study was to evaluate soil C stocks and C fractions up to 1 m depth in soils under different land use: 20 yr continuous cropping, warm season grass pasture and native forest in 32 sites distributed over the Chaco region. The organic C stock content up to 1 m depth expressed as equivalent mass varied as follows: forest (119.3 Mg ha−1) > pasture (87.9 Mg ha−1) > continuous cropping (71.9 and 77.3 Mg ha−1), with no impact of the number of years under cropping. The most sensitive organic carbon fraction was the coarse particle fraction (2000 μm–212 μm) at 0–5 cm and 5–20 cm depth layers. Resistant carbon (

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Effects of age and land-use changes on soil carbon and nitrogen sequestrations following cropland abandonment on the Loess Plateau, China

Ecological Engineering ◽

10.1016/j.ecoleng.2016.01.086 ◽

2016 ◽

Vol 90 ◽

pp. 105-112 ◽

Cited By ~ 41

Author(s):

Lei Deng ◽

Guo-liang Wang ◽

Guo-bin Liu ◽

Zhou-ping Shangguan

Keyword(s):

Land Use ◽

Soil Carbon ◽

Loess Plateau ◽

Land Use Changes ◽

The Loess Plateau ◽

Carbon And Nitrogen ◽

Cropland Abandonment ◽

Soil Carbon And Nitrogen

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Temporal variation of soil organic carbon and total nitrogen stock and concentration along land use, species and elevation gradient of chilimo dry afromonate forest and adjacent land uses, ethiopia

Natural Resources Conservation and Research ◽

10.24294/nrcr.v1i2.713 ◽

2018 ◽

Vol 1 (4) ◽

Author(s):

Mehari A. Tesfaye 1 ◽

Andres Bravo Oviedo 2 ◽

Felipe Bravo 3

Keyword(s):

Land Use ◽

Temporal Variation ◽

Mixed Model ◽

Linear Mixed Model ◽

Soil Depth ◽

Elevation Gradient ◽

Native Forest ◽

Carbon And Nitrogen ◽

Nitrogen Stock ◽

C And N

Forests play a vital role in the natural global carbon cycle by capturing carbon from the atmosphere through photosynthesis and converting it into forest biomass. Forests sequester and stores more carbon than any terrestrial ecosystem and act as sources as well as sinks of CO2. However, the increasing rate of deforestation and the impact of changes in land use require a critical and updated look at what is happening in the tropics. This work emphasized the temporal variation of bulk density, carbon (C) and nitrogen (N) stock and concentration in four land-use categories: natural forest, tree plantations, crop-land and degraded soil along elevation gradient and soil depth. The study was conducted in the Central Highlands of Ethiopia, where deforestation and human pressure on native forests are exacerbated and erosion has caused extensive soil loss. We hypothesized that, there is temporal variation of C and N concentrations and stocks in native forest along elevation gradient, land use type, species and soil depth. Carbon and N concentrations and stock and bulk densities in mineral soil were analysed as repeated measures in an irregular vertical space ranging from 0–10 cm, 10–30 cm, 30–50 cm and 50–100 cm, using a linear mixed model approach in two-time scale period 2012 - 2017. Double observations in 2012 and 2017, were made from the forest floor were analysed by a general linear mixed model. There is significant variation in organic carbon and nitrogen stock along elevation gradient for forest floor. Results also indicated that soil depth is more important factor than elevation gradient in native forests, though C and N concentrations and stocks diminished near human settlements. Native forest stored on average more nitrogen than bare soil, cropland and plantations, respectively. Conversion of crop and degraded land into plantations ameliorated soil degradation conditions, but species selection did not affect carbon and nitrogen stocks. Thus, appropriate forest management options should be applied in order to increase productivity and carbon sink of Chilimo dryafromontane forest and adjacent land use. Temporal monitoring and reporting of carbon stock and concentration is also important to understand the role of Chilimo dryafromonate forest in climate change mitigation and adaptation agendas.

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Changes in soil carbon, nitrogen and phosphorus due to land-use changes in Brazil

Biogeosciences Discussions ◽

10.5194/bgd-12-2533-2015 ◽

2015 ◽

Vol 12 (3) ◽

pp. 2533-2571 ◽

Cited By ~ 5

Author(s):

J. D. Groppo ◽

S. R. M. Lins ◽

P. B. Camargo ◽

E. D. Assad ◽

H. S. Pinto ◽

...

Keyword(s):

Land Use ◽

Soil Carbon ◽

Soil Phosphorus ◽

Land Use Changes ◽

Native Vegetation ◽

Nitrogen And Phosphorus ◽

Soil Layers ◽

Elemental Ratios ◽

Carbon And Nitrogen ◽

Original Vegetation

Abstract. In this paper soil carbon, nitrogen and phosphorus concentrations and related elemental ratios, as well as and nitrogen and phosphorus stocks were investigated in 17 paired sites and in a regional survey encompassing more than 100 pasture soils in the Cerrado, Atlantic Forest, and Pampa, the three important biomes of Brazil. In the paired sites, elemental soil concentrations and stocks were determined in native vegetation, pastures and crop-livestock systems (CPS). Overall, there were significant differences in soil element concentrations and ratios between different land uses, especially in the surface soil layers. Carbon and nitrogen contents were lower, while phosphorus contents were higher in the pasture and CPS soils than in forest soils. Additionally, soil stoichiometry has changed with changes in land use. The soil C : N ratio was lower in the forest than in the pasture and CPS soils; and the carbon and nitrogen to available phosphorus ratio (PME) decreased from the forest to the pasture to the CPS soils. The average native vegetation soil nitrogen stocks at 0–10, 0–30 and 0–60 cm soil depth layers were equal to approximately 2.3, 5.2, 7.3 Mg ha−1, respectively. In the paired sites, nitrogen loss in the CPS systems and pasture soils were similar and equal to 0.6, 1.3 and 1.5 Mg ha−1 at 0–10, 0–30 and 0–60 cm soil depths, respectively. In the regional pasture soil survey, nitrogen soil stocks at 0–10 and 0–30 soil layers were equal to 1.6 and 3.9 Mg ha−1, respectively, and lower than the stocks found in the native vegetation of paired sites. On the other hand, the soil phosphorus stocks were higher in the CPS and pasture of the paired sites than in the soil of the original vegetation. The original vegetation soil phosphorus stocks were equal to 11, 22, and 43 kg ha−1 in the three soil depths, respectively. The soil phosphorus stocks increased in the CPS systems to 30, 50, and 63 kg ha−1, respectively, and in the pasture pair sites to 22, 47, and 68 kg ha−1, respectively. In the regional pasture survey, the soil phosphorus stocks were lower than in the native vegetation, and equal to 9 and 15 kg ha−1 at 0–10 and 0–30 depth layer. The findings of this paper illustrate that land-use changes that are currently common in Brazil alter soil concentrations, stocks and elemental ratios of carbon, nitrogen and phosphorus. These changes could have an impact on the subsequent vegetation, decreasing soil carbon, increasing nitrogen limitation, but alleviating soil phosphorus deficiency.

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