Abstract:
Understanding how land use affects soil respiration (Rs) rates will assist us to comprehend
global CO
fluxes and develop land management plans. This study examines: (1) the impact
of land use on Rs in highland and midland agroecology; (2) the effects of land use on
heterotrophic (Rh) and autotrophic (Ra) soil respiration in the three contrasting agroecologies
Guder (2500–4232 m), Aba Gerima (1500–2500 m) and Dibatie (500–1500 m); (3) the effects
of land management practices on seasonal and diurnal Rs dynamics in highland; (4) and the
effects of soil amendments on Rs in midland agroecosystems. Data for Rs, soil moisture (S
2
),
and temperature (S
) were recorded monthly. One-way repeated measures ANOVA,
Friedman’s nonparametric test, paired t-test, regression, and correlation analysis were used
throughout the study. Based on the results, Rs rates were significantly (p = 0.004) higher in
khat plantations and teff cropland than in midland grazing land. On the other hand, in the
highlands, grazing land showed significantly higher Rs rates than Acacia decurrens and teff
cropland (p = 0.002). The Ra values of teff cropland in Guder and Aba Gerima were higher
than those of other land uses and lower than those of grazing land in Dibatie. Similarly, the
Rh of midland teff cropland was higher than that of other land uses. In the highlands, the Rh
values of Acacia plantations were higher than those of other land uses. The results indicated
that teff cultivation in relatively humid regions, Guder (1.36 CO
T
xix
2
μmol m
) and Aba
Gerima (2.08 CO
2
μmol m
–2
s
–1
) results in higher CO
fluxes into the atmosphere than Dibatie
(0.80 CO
2
μmol m
–2
s
–1
2
). Seasonal Rs rates were significantly different in different seasons
(autumn, p = 0.008; winter, p = 0.011; spring, p = 0.011; and summer, p = 0.038) between soil
bund and control plots in all seasons. The rate of daytime Rs was significantly higher (p =
0.0002) at 11 a.m. than at other times and lowest at 5 a.m. The Rs levels of B (4.23 ± 0.61
CO
2
μmol m
–2
s
–1
) and PAM+L (4.14 ± 0.57 μmol m
–2
s
–1
) were significantly higher than
those of PAM+B (3.43 ± 0.55 μmol m
–2
s
–1
) (p = 0.0003). Overall, different soil and soilrelated
factors, such as S
m
and S
, contributed to the variations in the Rs at the study sites.
However, in-depth research is needed to evaluate whether land use and management practices
significantly contribute CO
2
T
to the atmosphere or not.