EFFECT OF MULCHING MATERIALS AND FURROW IRRIGATION TECHNIQUES ON MAIZE (Zea mays L.) YIELD AND WATER PRODUCTIVITY AT WERER, MIDDLE AWASH VALLEY, ETHIOPIA

The climate change, water shortage and increasing evapotranspiration highlights the need to introduce water saving technologies for agricultural sustainability and crop production with a minimum input of water, mainly in semi-arid region. This experiment was conducted at Werer, Middle Awash Valley during the dry season of 2017/2018 to investigate the effects of mulching materials and furrow irrigation techniques on maize yield and water productivity under semiarid conditions. Split plot design with three replications, in which the irrigation techniques (Conventional, Fixed and Alternate Furrow) were assigned to main plot and the three mulching materials (no mulch, wheat straw and white plastic mulch), were to the subplot. The analysis of variance revealed that both grain yield and water productivity were affected by the main effect of furrow irrigation techniques and mulching materials (p≤ 0.05). The conventional furrow irrigation (8193 kgha-1) and white plastic mulch (7930 kg ha-1) resulted in the maximum grain yield. The alternate furrow irrigation (1.90 kg/m3) and the white plastic mulch (1.69 kg/m3) resulted in the maximum water productivity. Grain yield of maize recorded in conventional furrow was 16.28% higher than fixed furrow. Alternate furrow irrigation increased water productivity by 44.21% as compared to the conventional furrow. Plastic mulch increased maize grain yield by 11.08% and water productivity by 11.83% as compared to no mulch. Maize irrigated by alternate furrow irrigation resulted in 10.5% yield reduction as compared to conventional furrow irrigation. However, the 50% of water saved could irrigate a total additional area of 1ha. The highest benefit-cost ratio of (1.20) and net return of (49108 ETBha-1) were obtained from conventional furrow irrigation. Similarly, the highest net return of (53028 ETBha-1) and benefit-cost ratio of (2.16) was recorded from no mulch. Highest BCR, growth, yield and yield component of maize was recorded from conventional furrow irrigation. However, the highest water productivity was obtained from alternate furrow irrigation. Wheat straw mulch resulted in highest water productivity, better yield and economically feasible for maize production at Werer. This suggests that for maximizing grain yield under no water stress scenario, irrigation water could be used in conventional furrow irrigation without application of mulch. Under limiting irrigation water resource scenario and if the cost of irrigation water is high, irrigation could be done in alternate furrow irrigation along with wheat straw mulch to minimize evaporation loss, maximize water productivity and economically feasible for maize production at Werer and similar agro-ecology and soil type.