Dataset Information

Conversion of alpine pastureland to artificial grassland altered CO₂ and N₂O emissions by decreasing C and N in different soil aggregates.

ABSTRACT:

Background

The impacts of land use on greenhouse gases (GHGs) emissions have been extensively studied. However, the underlying mechanisms on how soil aggregate structure, soil organic carbon (SOC) and total N (TN) distributions in different soil aggregate sizes influencing carbon dioxide (CO₂), and nitrous oxide (N₂O) emissions from alpine grassland ecosystems remain largely unexplored.

Methods

A microcosm experiment was conducted to investigate the effect of land use change on CO₂and N₂O emissions from different soil aggregate fractions. Soil samples were collected from three land use types, i.e., non-grazing natural grassland (CK), grazing grassland (GG), and artificial grassland (GC) in the Bayinbuluk alpine pastureland. Soil aggregate fractionation was performed using a wet-sieving method. The variations of soil aggregate structure, SOC, and TN in different soil aggregates were measured. The fluxes of CO₂ and N₂O were measured by a gas chromatograph.

Results

Compared to CK and GG, GC treatment significantly decreased SOC (by 24.9-45.2%) and TN (by 20.6-41.6%) across all soil aggregate sizes, and altered their distributions among soil aggregate fractions. The cumulative emissions of CO₂ and N₂O in soil aggregate fractions in the treatments of CK and GG were 39.5-76.1% and 92.7-96.7% higher than in the GC treatment, respectively. Moreover, cumulative CO₂emissions from different soil aggregate sizes in the treatments of CK and GG followed the order of small macroaggregates (2-0.25 mm) > large macroaggregates (> 2 mm) > micro aggregates (0.25-0.053 mm) > clay +silt (< 0.053 mm), whereas it decreased with aggregate sizes decreasing in the GC treatment. Additionally, soil CO₂ emissions were positively correlated with SOC and TN contents. The highest cumulative N₂O emission occurred in micro aggregates under the treatments of CK and GG, and N₂O emissions among different aggregate sizes almost no significant difference under the GC treatment.

Conclusions

Conversion of natural grassland to artificial grassland changed the pattern of CO₂ emissions from different soil aggregate fractions by deteriorating soil aggregate structure and altering soil SOC and TN distributions. Our findings will be helpful to develop a pragmatic management strategy for mitigating GHGs emissions from alpine grassland.

SUBMITTER: Zhang M

PROVIDER: S-EPMC8759380 | biostudies-literature |

REPOSITORIES: biostudies-literature

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