干旱区生态环境知识资源中心

Different management practices may change the rate of soil respiration, thus affecting the carbon balance of grasslands. Therefore, we investigated the effect of grazing and mowing on soil respiration along with its driving variables (soil water content, soil temperature, above and below ground biomass, vegetation indices and soil carbon) in adjacent treatments (grazed and mowed) at a semi-arid grassland in Hungary (2011-2013). The average soil respiration over three years was higher in the mown (6.03 +/- A 4.07 A mu mol CO2 m(-2) s(-1)) than in the grazed treatment (5.29 +/- A 3.50 A mu mol CO2 m(-2) s(-1)). While soil water content and soil temperature did not differ between treatments, mowing resulted in 20 % higher soil respiration than grazing, possibly due to 17 % higher average above ground biomass in the mowed than in the grazed treatment. Inclusions of vegetation index VIGreen in the soil respiration model in addition to abiotic drivers improved the explained Rs variance by 16 % in the mowed and by 5 % in the grazed site, respectively. VIGreen alone proved to be a simple and fast indicator of soil respiration (r(2) = 0.31 at grazed, r(2) = 0.44 at mowed site). We conclude that soil respiration is responsive to the combined effect soil water content, soil temperature, biomass and soil carbon content as affected by the management (grazing vs. mowing) practice.