Evaluating The Effect Of Lake Beseka And Awash River Water Mix Ratios On Growth And Yield Of Cowpea (Vigna Unguiculata [L.] Walp) Forage Production

Abstract

Irrigation water is one of the most critical and scarce resource for agricultural production in arid and semiarid regions. Poor quality of irrigation water has adverse effect on soil and crop performance. During the last five decades the lake level and surface area have been increasing contentiously and this continuous expansion of Lake Beseka poses risk to Awash River because of its saline water. This study was undertaken to evaluate the different mixed irrigation water on growth, yield and quality of cowpea and identify suitable mixing ratio of Lake Beseka and Awash River water on cowpea production. Five mixed irrigation levels of Lake Beseka and Awash River water (2:98, 3:97, 5:95, 8:92 and 10:90) and a control (0:100 of Awash River) were used as a treatment. The treatments were arranged in randomized complete block design with three replications. The water analyses for the Awash River water indicate ECw with 0.30 dS/m, Sodium with 7.39, pH with 7.64 and RSC with 0.24meq/l which was within safe limit for irrigation purpose. While Beseka water quality indicates ECw with 4.4 dS/m, pH with 9.50, sodium with 4 and RSC with 21.40 which was not safe for irrigation purpose. Mixed Lake Beseka and Awash River water affect growth of cowpea in treatment T5 and T6 for EC 0.94 ds/m and 0.98 ds/m respectively. There was a highly significant (p<0.01) difference among yield and yield parameters due to blended water applications. The control treatment gave higher crop yield, number of seed per pod and number of pods per plant and shows no significant difference with mix ration of 2:98, 3:97 and 5:95 Beseka to Awash river water, respectively. The lowest crop yield and yield parameters were obtained from mix ratio of 10:90 Beseka to Awash River water and shows no significant differences with mix ratio of 8:92 Beseka to Awash river water. From result it is clear that mixing Lake Beseka with Awash River is safe up to 2-5% based on the quality of Awash River.