Assessing stock and thresholds detection of soil organic carbon and nitrogen along an altitude gradient in an east Africa mountain ecosystem

Njeru, Crispus Mugambi; Ekesi, Sunday; Mohamed, Samy Abd El-Malik; Kinyamario, JI; Kiboi, Samuel; Maeda, Eduardo Eiji

doi:10.1016/j.geodrs.2017.04.002

Cited by 39 publications

(19 citation statements)

References 34 publications

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“…6). This finding is in agreement with the conclusions of other studies (Njeru et al, 2017;Ou et al, 2017). Soil pH influences SOC and STN by regulating the microbial structure, function and activities (Bai et al, 2002).…”

Section: Soc and Stn Relationships With Soil Propertiessupporting

confidence: 93%

“…6). This relationship has also been recognized by other studies (Zhang et al, 2016;Njeru et al, 2017). The SOC and STN concentrations were negatively correlated with BD, possibly because the mineralization of SOC and the nitrification of ammonium nitrogen were suppressed in soils with high BD values (De Neve and Hofman, 2000).…”

Section: Soc and Stn Relationships With Soil Propertiessupporting

confidence: 80%

“…SOC and STN also change along elevation gradients, as different elevations are characterized by different climatic conditions (Tsui et al, 2013). SOC generally increases with increasing elevation (Tsai et al, 2010;Njeru et al, 2017). In addition to climate, soil properties, such as pH (Ou et al, 2017), bulk density (Hossain et al, 2015;Chen et al, 2017), total phosphorus Tian et al, 2017) and soil moisture content (Singh et al, 2011;Zhao et al, 2016), are also strongly related to SOC and STN.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of soil organic carbon and total nitrogen under various grassland types along a transect in a mountain-basin system in Xinjiang, China

Nan

et al. 2018

J. Arid Land

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Soil organic carbon (SOC) and soil total nitrogen (STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosystem processes and global climate feedbacks. Grassland ecosystems of Funyun County in the southern foot of the Altay Mountains are characterized by complex topography, suggesting large variability in the spatial distribution of SOC and STN. However, there has been little investigation of SOC and STN on grasslands in arid regions with a mountain-basin structure. Therefore, we investigated the characteristics of SOC and STN in different grassland types in a mountain-basin system at the southern foot of the Altai Mountains, north of the Junggar Basin in China, and explored their potential influencing factors and relationships with meteorological factors and soil properties. We found that the concentrations and storages of SOC and STN varied significantly with grassland type, and showed a decreasing trend along a decreasing elevation gradient in alpine meadow, mountain meadow, temperate typical steppe, temperate steppe desert, and temperate steppe desert. In addition, the SOC and STN concentrations decreased with depth, except in the temperate desert steppe. According to Pearson's correlation values and redundancy analysis, the mean annual precipitation, soil moisture content and soil available N concentration were significantly positively correlated with the SOC and STN concentrations. In contrast, the mean annual temperature, pH, and soil bulk density were significantly and negatively correlated with the SOC and STN concentrations. The mean annual precipitation and mean annual temperature were the primary factors related to the SOC and STN concentrations. The distributions of the SOC and STN concentrations were highly regulated by the elevation-induced differences in meteorological factors. Mean annual precipitation and mean annual temperature together explained 97.85% and 98.38% of the overall variations in the SOC and STN concentrations, respectively, at soil depth of 0-40 cm, with precipitation making the greatest contribution. Our results provide a basis for estimating and predicting SOC and STN concentrations in grasslands in arid regions with a mountain-basin structure.

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Section: Soc and Stn Relationships With Soil Propertiessupporting

confidence: 93%

Section: Soc and Stn Relationships With Soil Propertiessupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

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Characteristics of soil organic carbon and total nitrogen under various grassland types along a transect in a mountain-basin system in Xinjiang, China

Nan

et al. 2018

J. Arid Land

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“…However, the amount of soil chemical elements in the studied area showed an increasing trend for organic carbon content along the gradient. A significant increase of soil organic carbon with increasing altitude was shown in other studies (Njeru et al 2017;Sierra et al 2017). However, there is no stable pattern between the distribution of soil organic carbon and altitude.…”

Section: Discussionsupporting

confidence: 66%

Variations of soil physicochemical properties and vegetation cover under different altitudinal gradient, western Hyrcanean forest, north of Iran

Pourbabaei¹,

Salehi²,

Ebrahimi³

et al. 2020

J. For. Sci.

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This study was done to quantify the amount of soil organic matter and to evaluate physicochemical properties and vegetation cover changes along the altitudinal gradient. Nine altitudinal transects were selected from 100 m a.s.l. to 1 700 m a.s.l. Then, 160 circular plots of 1 000 m2 area with a distance of 150 m from each other were studied. Soil texture, bulk density, particle density, soil base saturation, phosphorus and potassium values did not indicate any specific variation pattern. Whereas pH decreased powerfully, the highest and the lowest value of pH was measured at 100 m a.s.l. and 1 700 m a.s.l., respectively. Soil organic carbon content increased significantly with increasing altitude (P ≤ 0.01). Density of trees decreased dramatically from 100 to 900 m a.s.l., whereas this trend was ascending from 1 100 to 1 700 m a.s.l. Density of shrub species increased with increasing altitude along the gradient and the highest value was revealed at 1 300 m a.s.l. The highest percentage of herbaceous species cover was found at a lower altitude and a decreasing trend was found along the altitudinal gradient.

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“…2, 4 and 5). This negative correlation relationship has been exhibited in other studies (Njeru et al, 2017). This was due to the suppression of possibly the process of mineralization and nitri cation in soils with high soil density values (De Neve and Hofman, 2000).…”

Section: Factors Affecting Toc and Tn Vertical Distribution During Sosupporting

confidence: 74%

Combined Use of Carbon and Nitrogen Isotopes for Assessment of Soil Organic Matter Sources and Decomposition in a Typical Karst Area of Yunnan–Guizhou Plateau, Southwestern China

Beckford¹,

Song²,

Chang³

et al. 2021

Preprint

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Soil organic matter (SOM) has substantial influence on geochemical cycle, soil stability and global climate change, however total organic carbon sequestration mechanisms in karst soil remain poorly understood. For this study we assess, total organic content (TOC), total nitrogen (TN), C/N ratio and isotopes of carbon and nitrogen in four soil profiles over critical karst area to investigate organic matter source, mechanisms that influence fractionation and factors affecting SOM in Yunnan–Guizhou Plateau, Southwestern China. The results revealed that SOM comprised of mixed sources derived from both exogenous and endogenous materials. The soil profiles indicate intense vertical variation in δ13C and δ15N with an increase in both isotopes in the upper layers, deceased in δ13C below 20 cm and irregular fluctuation in δ15N with depth. Mechanisms such as mineralization and selective preservation influence isotopic fractionation in the upper soil surface, while translocation, nitrification and denitrification dominated the subsoil layers. Variation in TOC, TN and stable carbon and nitrogen isotopes were influence by vegetation cover, topography, soil water and external contribution. Moreover, the decrease in TOC and TN with depth were due to downward translocation of dissolved organic carbon and nitrogen caused by monsoon climate. Our results revealed that combination of TOC, TN, C/N, δ13C and δ15N can be used as proxy to decipher SOM source, external influence and stability of karst soils. Furthermore, the intense change in δ13C and δ15N throughout the soil profiles suggest that this karst soil is unstable which have implications for land management and carbon sequestration.

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Assessing stock and thresholds detection of soil organic carbon and nitrogen along an altitude gradient in an east Africa mountain ecosystem

Cited by 39 publications

References 34 publications

Characteristics of soil organic carbon and total nitrogen under various grassland types along a transect in a mountain-basin system in Xinjiang, China

Characteristics of soil organic carbon and total nitrogen under various grassland types along a transect in a mountain-basin system in Xinjiang, China

Variations of soil physicochemical properties and vegetation cover under different altitudinal gradient, western Hyrcanean forest, north of Iran

Combined Use of Carbon and Nitrogen Isotopes for Assessment of Soil Organic Matter Sources and Decomposition in a Typical Karst Area of Yunnan–Guizhou Plateau, Southwestern China

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