Spatiotemporal variations of soil respiration under different land uses and their control in Northwestern Ethiopia

Understanding the dependence of soil respiration (Rs) on land use can improve our understanding of global carbon dioxide fluxes and provide useful information for designing land management options. In this study, we examine the spatiotemporal variability of Rs and the factors that influence it. Mean Rs was significantly higher (p < 0.05) in the teff farmland (TC) and khat plantation (KP) than in grazing land (GL) in the midland; Rs rates were significantly higher (p < 0.05) in GL than A. decurrens (AP) and TC in the highland area. In the highlands, seasonal variation of Rs was significantly (p < 0.05) greater in autumn in GL than in TC and AP, but in winter, Rs varied significantly (p < 0.05) more in AP than in TC and GL. In the midland, TC had significantly (p < 0.05) higher Rs than GL in autumn. In addition, TC and KP had significantly higher Rs than GL in winter and spring. In the highlands, S-T explained 0.02-45% Rs variation using the exponential model; however, in the midlands, S-T explained 5-28%. In the midland, the quadratic function explained 32-89% of the variation in the seasonal Rs rates based on S-M, while in the highlands, it explained 11-66%. Moreover, multiple regressions explained 57-80% of the variation in annual Rs rates in midlands based on S-T and S-M, while they explained only 12-32% in the highlands. Thus, Rs was mainly influenced by environmental factors, although it varied spatially and temporally.