Land use change decreases soil carbon stocks in Tibetan grasslands

Qiao, Ning; Xu, Xingliang; Cao, Guangmin; Ouyang, Hao; Kuzyakov, Yakov

doi:10.1007/s11104-015-2556-8

Cited by 20 publications

(20 citation statements)

References 50 publications

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“…Organic N decomposition and inorganic N supply is usually slow in cold regions due to decelerated microbial activity [19]. Livestock consumed 29.22 kg N ha -1 one year in alpine meadow ecosystem at medium grazing intensity, but returned only 6.20 kg N ha -1 into soils by excreting urine and dung [5]. Grazing significantly decreased soil total nitrogen and N recycling rates [19].…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, grasslands covered 41.7% of the area of China, and these were mainly distributed in the north and northwest, and on the Tibetan Plateau at very high elevations (over 4,000 m). Because of the extensive ecological and economic importance of an alpine meadow, many attempts have been made to conserve its surrounding [5].…”

Section: Introductionmentioning

confidence: 99%

“…Overgrazing was the most significant factor causing grassland degradation [5,7]. Previous studies showed that grazing altered plant-competitive interactions, decreasing the cover of Gramineae and increasing the cover of forbs for alpine meadow [8].…”

Section: Introductionmentioning

confidence: 99%

“…The higher δ 15 N values indicated the accelerated N cycling and rich supply [11]. Grazing intensity significantly decreased soil available N and δ 15 N in alpine meadow [5,[14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Grazing reduced soil δ 15 N from 5.8-6.8‰ for Elymus pasture to 4.3-5.7‰ for Kobresia pasture on the Tibetan alpine grasslands [5]. Soil δ 15 N values decreased significantly from 5.25‰ to 4.67‰ with grazing in the steppe [16].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Grazing Intensity on Soil and Plant δ15N of an Alpine Meadow

Du¹,

Guo²,

Zhang³

et al. 2017

Pol. J. Environ. Stud.

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The mechanisms underlying the retention of inorganic N were still not well understood in an alpine meadow on the Tibetan Plateau as well as in other high-altitude meadow sites greatly grazed and disturbed. We conducted field soil and dominant species foliar nitrogen natural abundance of stable isotope ratios N value of surface soil was mainly affected by soil total nitrogen. Furthermore, the degree of nitrogen limitation increased with grazing elevation for sedge family and Gramineae family plants.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The higher δ 15 N values indicated the accelerated N cycling and rich supply [11]. Grazing intensity significantly decreased soil available N and δ 15 N in alpine meadow [5,[14][15].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of Grazing Intensity on Soil and Plant δ15N of an Alpine Meadow

Du¹,

Guo²,

Zhang³

et al. 2017

Pol. J. Environ. Stud.

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Fate of Organic and Inorganic Nitrogen in Crusted and Non‐Crusted Kobresia Grasslands

et al. 2016

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A widespread pattern of the Tibetan plateau is mosaics of grasslands of Cyperaceae and grasses with forbs, interspersed with patches covered by lichen crusts induced by overgrazing. However, the fate of inorganic and organic N in non‐crusted and crusted patches in Kobresia grasslands remains unknown. We reported on a field 15N‐labeling experiment in two contrasting patches to compare retention of organic and inorganic N over a period of 29 days. 15N as KNO3, (NH4)2SO4 or glycine was sprayed onto soil surface. Crusted patches decreased plant and soil N stocks. More 15N from three N forms was recovered in soil than plants in both patches 29 days after the labeling. In non‐crusted patches, 15N recovery by the living roots was about two times higher than in crusted ones, mainly because of higher root biomass. Microorganisms in non‐crusted patches were N‐limited because of more living roots and competed strongly for N with roots. Inorganic N input to non‐crusted patches could alleviate N limitation to plants and microorganisms, and leads to higher total 15N recovery (plant + soil) for inorganic N forms. Compared to non‐crusted patches, microorganisms in crusted patches were more C‐limited because of depletion of available C caused by less root exudation. Added glycine could activate microorganisms, together with the hydrophobicity of glycine and crusts, leading to higher 15N‐glycine than inorganic N. We conclude that overgrazing‐induced crusts in Kobresia grasslands changed the fate of inorganic and organic N, and lead to lower total recovery from inorganic N but higher from organic N. Copyright © 2016 John Wiley & Sons, Ltd.

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Fertilization with nitrogen and/or phosphorus lowers soil organic carbon sequestration in alpine meadows

Hou

Zhang

et al. 2018

Land Degrad Dev

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Nutrient additions can increase carbon (C) inputs to soil, but there is no consensus about the response of soil organic C (SOC) storage and C sequestration. For the Tibetan alpine meadows, little is known about the effects and mechanisms of nitrogen (N) and phosphorus (P) addition on SOC stocks. In this study, we applied N and/or P fertilization for 7 years and analyzed soil changes in bulk density, pH, SOC, soil inorganic C (SIC), δ13C, and microbial biomass C (MBC), as well as stocks of SOC, SIC, and MBC for soil to a depth of 40 cm. We found that C:N decreased in 0–20 cm, and pH decreased at both 0–20 cm and 20–40 cm after fertilization. Fertilization with N and/or P decreased SOC stocks in 0–20 cm by 5–12% and SOC stocks from 0 to 40 cm by 3–5%. This SOC stock decline was associated with changes in SOC concentration but not with changes in bulk density. The SIC stock was 18% of total soil C, and was not influenced by either N or P fertilization. Soil δ13C in the 0–20 cm layer was depleted by fertilization with N or N + P, whereas P enriched soil δ13C. Soil MBC was positively correlated with SOC concentration, whereas soil δ13C was negatively correlated with SOC concentration. Soil δ13C, as a proxy of decomposition rate, indicated potentially higher SOC decomposition under N fertilization. These findings suggest that fertilization with N and/or P lowered SOC sequestration in Tibetan alpine meadows.

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Land use change decreases soil carbon stocks in Tibetan grasslands

Cited by 20 publications

References 50 publications

Effect of Grazing Intensity on Soil and Plant δ15N of an Alpine Meadow

Effect of Grazing Intensity on Soil and Plant δ15N of an Alpine Meadow

Fate of Organic and Inorganic Nitrogen in Crusted and Non‐Crusted Kobresia Grasslands

Fertilization with nitrogen and/or phosphorus lowers soil organic carbon sequestration in alpine meadows

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