Differential response of microbial respiration to supplied nitrogen forms in 3 contrasting alpine meadow soils on the Tibetan Plateau

ABSTRACT: An incubation experiment was conducted to examine the effects of nitrogen (N) applications in different forms (NH 4 NO 3 , NH 4 Cl, and KNO 3 ) on microbial respiration considering 3 different alpine meadow soils (C poor soil, pH = 8.1, 1.6% C; C moderate soil, pH = 6.0, 5.0% C; C rich soil, pH = 7.1, 7.4% C) in the Tibetan Plateau. The addition of NH 4 NO 3 and NH 4 Cl increased the microbial respiration in C poor soil, but KNO 3 had no effect. The inorganic N forms had no effects on C rich soil, but decreased microbial SOIL AND PLANT NUTRITION - Article Differential response of microbial respiration to supplied nitrogen forms in 3 contrasting alpine meadow soils on the Tibetan Plateau Xiaoyang Zeng* Sichuan College of Architectural Technology - Department of Landscape Architecture - Chengdu (Sichuan), China. *Corresponding author: zengxy@sina.cnReceived: Apr. 26, 2016 – Accepted: Oct. 3, 2016 respiration in C moderate soil. Soil microbial respiration levels across the different types were ordered as follows: C poor soil < C rich soil < C moderate soil, regardless of N addition. These results suggest that the effect of N on microbial respiration in alpine meadow soils is more dependent on the initial soil pH than on soil C availability.