Abstract
Soil carbon dioxide emission: soil respiration is representing a major contributor of accumulating carbon dioxide in the atmosphere that aids to accelerate global warming and altering the climate. Soil temperature, soil water content, sun light and vegetation are considered most common regulators of soil respiration variations in ecosystem. The soil respiration was measured in grassland intended to examine how the soil respiration changed with varying climatic factors, for two years (2015 and 2016) in temperate grassland of Annapurna Conservation Area (ACA), Nepal. In the study, soil temperature accounted exponential function of soil respiration variation at 42.9%, 19.1% and 23.3%, and temperature sensitivity of the soil respiration (Q10) obtained at 6.2, 1.4 and 1.8 in October 2015 and April 2016 and both the measurements were combined, respectively. Significant negative (R2 = 0.50, p < 0.05, October 2015) and positive (R2 = 0.084, p < 0.05, April 2016) exponential function of soil respiration and soil water content were determined, where high soil respiration values were always measured between 30% and 35% of the soil water content. However, linear significant relationship was determined (R2 = 0.376, p < 0.05) between soil respiration and photosynthetic photon flux density (PPFD). Soil respiration value averaged in October 2015 was 357 mg CO2 m-2 h-1 and in April 2016 it was 444.6 mg CO2 m-2 h-1. Above- and below-ground plant biomasses were obtained at 231.1 g d w m-2 and 1538.8 g d w m-2 in October, and at 449.9 g d w m-2 and 349.0 g d w m-2 in April, respectively. This study showed variation of soil respiration in relation to the factors such as soil temperature, soil water content and photosynthetic photon flux density signifying their importance in governing ecosystem function and carbon balance of the temperate grassland ecosystem.
Highlights
Soil is a good resource to human kinds as it is dynamic to accumulate more carbon than atmosphere and vegetation [1] [2]
This study showed variation of soil respiration in relation to the factors such as soil temperature, soil water content and photosynthetic photon flux density signifying their importance in governing ecosystem function and carbon balance of the temperate grassland ecosystem
The temperature sensitivity of soil respiration (Q10) obtained was comparatively high in October (Q10 = 6.2) at lower range of soil temperature than the higher range in April (Q10 = 1.4) which showed that the temperature sensitivity of soil respiration decreased with increasing temperature range
Summary
Soil is a good resource to human kinds as it is dynamic to accumulate more carbon than atmosphere and vegetation [1] [2]. The majority of additional atmospheric carbon dioxide comes naturally from soil through soil respiration. This phenomenon is a combined metabolic activity of roots and microorganisms generated mainly from soil surface by respiration and decomposition, respectively and it is considered the largest component of carbon cycling in grassland ecosystems [19] [20] [21] [22]. The soil carbon dioxide emission in respiration, as much as 50% - 90% of the annual gross primary productivity returns back to the atmosphere [23] depending on biotic and abiotic factors [24] [25] [26] [27] [28]. The soil respiration response to these drivers varies among ecosystems, forest, grassland and tundra [22], and eco-regions [33]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
