Building resilience against drought and soil erosion: impact of field water conservation in the drought prone Vertisol areas of northern Ethiopia

Field water conservation practices are a way forward to build resilience against drought through increasing productive green water and crop yield, while reducing runoff (blue water) and soil erosion. A long-term tillage experiment was carried out (2005 to 2011) on a Vertisol to quantify the impact of field water conservation practices on soil moisture, runoff, soil loss and crop yield in a rainfed field in northern Ethiopia. The experimental layout was a randomized complete block design with three replications on permanent plots of 5 m by 19 m. The tillage treatments were (i) derdero+ (DER+) with a furrow and permanent raised bed planting system, 30% standing crop residue retention and no-tillage on top of the bed, (ii) terwah+ planting system (TER+) with ploughing once at sowing, 30% standing crop residue retention and fresh broad beds, and (iii) conventional tillage (CT) with a minimum of three tillage operations and removal of crop residues. The crops grown in rotation were wheat, barley, teff and grass pea. The field conservation practices thus combined indigenous conservation practices (derdero and terwah) with the concepts of conservation agriculture (hence the ‘+’). Data on soil loss, runoff, soil moisture, crop yield and NDVI were collected. Significantly different (p<0.05) mean soil losses of 4.4, 12.5 and 18 t/ha/y were recorded for DER+, TER+ and CT, respectively. Similarly, the mean runoff was 458, 706 and 925 m3/ha/y from treatments with DER+, TER+ and CT, respectively. The average grain yield of wheat over three years was 2.46, 2.02 and 1.61 t/ha for DER+, TER+ and CT, respectively. NDVI records in wheat and grass pea were higher in DER+.Field water conservation practices are a way forward to build resilience against drought through increasing productive green water and crop yield, while reducing runoff (blue water) and soil erosion. A long-term tillage experiment was carried out (2005 to 2011) on a Vertisol to quantify the impact of field water conservation practices on soil moisture, runoff, soil loss and crop yield in a rainfed field in northern Ethiopia. The experimental layout was a randomized complete block design with three replications on permanent plots of 5 m by 19 m. The tillage treatments were (i) derdero+ (DER+) with a furrow and permanent raised bed planting system, 30% standing crop residue retention and no-tillage on top of the bed, (ii) terwah+ planting system (TER+) with ploughing once at sowing, 30% standing crop residue retention and fresh broad beds, and (iii) conventional tillage (CT) with a minimum of three tillage operations and removal of crop residues. The crops grown in rotation were wheat, barley, teff and grass pea. The field conservation practices thus combined indigenous conservation practices (derdero and terwah) with the concepts of conservation agriculture (hence the ‘+’). Data on soil loss, runoff, soil moisture, crop yield and NDVI were collected. Significantly different (p