Peer review

Conservation agriculture (CA) is common globally but not in tropical Africa, including Ethiopia. Conservation agriculture was evaluated at Bako (short-term CA study) and Melkassa (medium-term CA study) in Ethiopia for effects on crop yield and soil properties. Results showed the rate of water infiltration was 16% more at Bako and 15% less at Melkassa for conventional practice (CP) (tillage plus crop residue removal) compared with CA (no tillage plus residue retention). Time-to-pond was doubled and soil penetration resistance was 7 kP less for the 0–0.1 m depth with CA maize (Zea mays L.)–dry bean (Phaseolus vulgaris L.) rotation compared to CP maize monoculture at Melkassa. Soil organic C for the 0–0.05 m soil profile was 16 g kg-1 with CA compared with 12 g kg-1 for CP and early maize growth was slower with CA compared with CP at Melkassa. Maize stover yield was 10.14 Mg ha-1 for CP compared with 9.01 Mg ha-1 for CA in 2015 at Bako, but maize yields were greater with CA at Melkassa in 2016. Monoculture and intercrop dry bean, respectively, had 40 and 32% more grain yield with CA compared to CP in 2016 at Melkassa. It was concluded that medium-term beneficial effects of CA on soil properties and crop productivity can be expected at Melkassa, but any short-term benefits of CA at Bako were uncertain.

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