Author(s)

Lihua Zhang¹, Longyu Hou², Hendrikus J. Laanbroek^3,4, Dufa Guo⁵, Qibing Wang^1*

¹State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
¹State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sci-ences, Beijing, China.
²Department of Grassland Science, China Agricultural University, Beijing, China.
³Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
⁴Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands.
⁵Shandong Normal University, Jinan, China.

Grazing and mowing are two common practices for grassland management. Mowing is now recommended as an alternative to the traditional grazing for grassland conservation in Inner Mongolia, northern China. Many studies have revealed that mowing may alter ecosystem properties in various ways. However, little attention has been paid to the effect of mowing on trace gas emissions, especially on N₂O flux. We conducted an experiment to investigate the effects of mowing on N₂O fluxes from the semiarid grassland in Inner Mongolia. The mowing experiment, which started in 2003, comprised four mowing intensity treatments, i.e. mowing heights at 2 cm, 5 cm, 10 cm and 15 cm above the soil surface, respectively, and a control (non-mowing), with five replicates. Gas fluxes were measured through a closed static chamber technique during the growing seasons (usually from May to September, depending on local climate at the time) of 2008 and 2009, respectively. Our results showed that mowing decreased N₂O emissions, above-ground biomass and total litter production. N₂O emissions were greater in May and June than in other sampling periods, regardless of treatments (P < 0.05). A co-relationship analysis suggested that variations in seasonal N₂O fluxes were mainly driven by variations in soil moisture, except in July and August. In July and August, above-ground plant biomass and soil total nitrogen became the major drivers of N₂O fluxes under the soil temperatures between 16 ° C and 18 ° C. Though there were some uncertainties due to the low frequency of N₂O flux measurement, our study mainly indicated that 5 cm mowing height might decrease N₂O emissions in grasslands during the growing season, and soil properties affected the magnitude of the reduction.

N₂O Fluxes, Mowing, Soil Moisture, Soil Microbial Carbon Biomass, Soil Organic Carbon

Zhang, L. , Hou, L. , Laanbroek, H. , Guo, D. and Wang, Q. (2015) Effects of Mowing Heights on N₂O Emission from Temperate Grasslands in Inner Mongolia, Northern China. American Journal of Climate Change, 4, 397-407. doi: 10.4236/ajcc.2015.45032.