Population growth and increasing resource demands in Ethiopia are stressing and degrading agricultural landscapes. Most Ethiopian soils are already exhausted by several decades of over exploitation and mismanagement. Since many agricultural sustainability issues are related to soil quality, its assessment is very important. We determined integrated soil quality indices (SQI) within the surface 0–15 cm depth increment for three agricultural land uses: rain fed cultivation (RF); agroforestry (AF) and irrigated crop production (IR). Each land use was replicated five times within a semi-arid watershed in eastern Tigray, Northern Ethiopia. Using the framework suggested by Karlen and Stott (1994); four soil functions regarding soil’s ability to: (1) accommodate water entry (WE); (2) facilitate water movement and availability (WMA); (3) resist degradation (RD); and (4) supply nutrients for plant growth (PNS) were estimated for each land use. The result revealed that AF affected all soil quality functions positively more than the other land uses. Furthermore, the four soil quality functions were integrated into an overall SQI; and the values for the three land uses were in the order: 0.58 (AF) > 0.51 (IR) > 0.47 (RF). The dominant soil properties influencing the integrated SQI values were soil organic carbon (26.4%); water stable aggregation (20.0%); total porosity (16.0%); total nitrogen (11.2%); microbial biomass carbon (6.4%); and cation exchange capacity (6.4%). Collectively, those six indicators accounted for more than 80% of the overall SQI values.

Sustainability of an agricultural system depends on its carbon (C) footprint. Thus, major C-inputs and C-outputs of the smallholder crop-livestock mixed farming systems in Ethiopia were collated and their C-equivalence and sustainability indices (CSI) were computed. C-based inputs increased twofold from the lowest (0.32TgCeq y⁻¹) in 1994 to the highest (0.62TgCeq y⁻¹) in 2010. Similarly, total C-output increased linearly from the lowest (30TgCeq y⁻¹) in 1994 to the highest (62TgCeq y⁻¹) in 2010 and 2011. Livestock contributed much of the C-output. Further, the average rate of increase in C-output from 1994 to 1999 was marginal, i.e., 0.67TgCeq y⁻¹, but the 11-year average rate of increase from 2000 to 2011 was relatively higher, i.e., 2.2TgCeq y⁻¹. The relationship between annual total C-based input and output was strong (r² = 0.88; P < 0.001). The CSI of the smallholder agricultural production systems in Ethiopia was relatively high, with the 18-year average value being ˜110 when compared with other regions.