Evaluating conservation tillage as a strategy for soil and water conservation and yield stability in Ethiopian dryland agriculture

Traditional agricultural management relying on intense cultivation with the conventional tillage has triggered widespread soil nutrient loss, land degradation, and rapid moisture evaporation across sub-Saharan Africa, jeopardizing food security in the fragile highland ecosystems of Northern Ethiopia. To evaluate sustainable, climate-resilient alternatives, a two-year field experiment was conducted over consecutive cropping seasons (2019–2020) at the Shire-May-Tsebri Agricultural Research Center using a Randomized Complete Block Design with four replications to test five tillage treatments: Zero Tillage (ZT), Mulch Tillage (MT), Reduced Tillage (RT), Strip Tillage (ST), and Conventional Tillage (CT). By testing soil moisture at different depths down to 60 cm, we found that conservation tillage works much better than traditional plowing. It improves the soil’s structure and helps it hold onto more water. In the immediate topsoil layer (0–15 cm), MT and ZT suppressed surface evaporation most effectively, boosting seasonal moisture retention by 103.5% and 76.8% over CT, respectively, while within the sub-surface strata, ST established a definitive hydrological buffer that secured independent moisture premiums of 32.5% (15–30 cm) and 36.3% (30–45 cm) over the control. Physically, ST optimized structural soil health by minimizing bulk density and increasing Total Porosity to 51.75% (versus 49.65% in CT), although short-term management did not induce significant variations in stable chemical parameters such as Organic Carbon, Total Nitrogen, or soil pH. Agronomical, the superior sub-surface water retention and structural improvements under Strip Tillage translated into a highly significant 47.9% crop productivity premium, generating a mean maize ( Zea mays L.) grain yield of 4.60 t/ha compared to only 3.11 t/ha in CT. Ultimately, this study demonstrates that immediate physical and hydrological restoration of degraded drylands can be achieved through minimized soil disturbance, indicating that the broad-scale extension adoption of Strip Tillage and Mulch Tillage is an effective strategy to buffer crops against dry spells and optimize smallholder climate resilience in semi-arid farming systems.