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Accueil du site → Doctorat → Autriche → Carbon, nitrogen and mineral nutrients in soils under steppe and Larix sibirica-forest at the Darkhad Depression, Northern Mongolia

Universität für Bodenkultur Wien (2005)

Carbon, nitrogen and mineral nutrients in soils under steppe and Larix sibirica-forest at the Darkhad Depression, Northern Mongolia

Amgalan, Minjigmaa

Titre : Carbon, nitrogen and mineral nutrients in soils under steppe and Larix sibirica-forest at the Darkhad Depression, Northern Mongolia

Auteur : Amgalan, Minjigmaa

Akad. Grad : Dr. nat. techn. Wien, Univ. für Bodenkultur, Diss., 2005

Université de soutenance : Universität für Bodenkultur Wien | Department für Wald- und Bodenwissenschaften | Institut für Waldökologie

Résumé
This study was carried out at the Darkhad Depression, which lies in the Khuvsgul Province, Northern Mongolia, at a latitude of 50o30’N - 51o50’N and a longitude of 99o00’E - 99o55’E. The most important settlements are Ulaan-Uul, Renchinlkhumbe and Tsagaan Nuur, the, lowest elevation is 1.530 m asl. The Darkhad Depression is a transition zone between the Great Siberian boreal forest and the Central Asian steppe desert. In recent years, forest acreage has decreased ; due to fire, insects, low precipitation, and human activity. Consequently the steppe area is increasing. This research established a dataset of soil chemical properties and carbon stores in forest and steppe soils at four research sites in the Darkhad Depression. Aside from organic matter carbon (SOC), inorganic soil carbon (SIC) of geogenic and pedogenic origin was determined, because of its importance for the estimation of carbon pools and fluxes in terrestrial ecosystems, as well as the influence of past climatic conditions. For this part of Mongolia no data existed on the chemical properties and carbon accumulation in forest and steppe soils as well as on soil forming minerals. Soil sampling was done by replicate coring along transects from inside the forest out to the steppe. The forest edge was part of the sampling transects, as it is a zone of deposition of wind transported materials such as plant debris, dust and snow. Soil samples were analyzed for SOC and SIC, nitrogen, macro- and microelements and exchangeable cations. In addition particle size, bulk mineral and clay mineral analyses we made. The distribution of macro- and microelements and exchangeable cations showed no consistent significant differences between inside the Larix sibirica forest, the forest edge and the steppe soils. However, they were different at lower slope research sites such as the Tsagaan Nuur research site. The distribution of macro- and microelements as well as of exchangeable cations depends on soil slope position and soil types such as permafrost effected soils at the Renchinlkhumbe and Tsagaan Nuur research sites. Correlation analysis was used to indicate correlations among soil analytical data, such as the strong positive correlation between SOC and nitrogen or the negative correlation between SOC and potassium, due to insufficient input as SOC accumulates

Mots clé : Bodenkunde / Kohlenstoff / Larix sibirica / Mineralstoffe / Mongolei / Stickstoff — Enviromental sciences / Larix sibirica / Mongolia / carbon / mineral nutrients / soil

Présentation : Österreichische Dissertationsdatenbank

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