Identification of best maize-legume based cropping systems under conservation agriculture practices for Central Rift Valley of Ethiopia

Cereal crops especially maize production in Ethiopian Central Rift Valley is affected by biotic and abiotic production. This study was conducted for two seasons (2015-2016) and the best cropping system was identified using Randomized Complete Block Design with three replications. The experiment had six treatments (1) Continuous mono-cropping under conventional practice (CN), (2) continuous mono cropping under conservation agriculture (CA) (3) relay cropping (CA) with double bean planting within a season (maize bean inter-cropping: second round bean planting was conducted after immediate harvesting of the first bean), (4) Double cropping (CA) (maize bean inter cropping after sole lablab), (5) Double cropping (CA) (maize after bean) and (6) Double cropping (CA) (bean after maize). In 2016, the highest maize biomass yield and maximum water use efficiency were obtained from double cropping bean after maize with value of 16050 kg/ha and 31 kg mm-1, respectively. Maize-bean relay cropping outperformed the sole maize under CA and CN by 182 and 138% for maize grain yield. Water use efficiency of double cropping (maize after bean) and relay cropping was higher than double cropping (bean after maize) by 366 and 197% in 2015 for maize grain yield. For biomass, relay cropping under CA and sole maize under CN had similar water use efficiency of 18 kg mm-1. The CA practice with diverse crops planted together: double inter-cropping at different time (relay cropping) and double cropping under CA are good options for using the residual soil moisture and to sustainably improve crop productivity. Key words: Conservation; cropping system; lablab; water use efficiency.