EFFECT OF ALTERNATE FURROW IRRIGATION UNDER DIFFERENT MOISTURE REGIMES ON WATER USE EFFICIENCY, GROWTH, YIELD AND YIELD COMPONENTS OF COMMON BEAN (Phaseolus vulgaris L.) AT ALAGE, CENTRAL RIFT VALLEY OF ETHIOPIA

Abstract

The farmers use common traditional irrigation methods which at times lead them to over irrigate, resulting in high water losses and low irrigation efficiency. Under such conditions understanding and application use of deficit and alternate furrow irrigation systems on crop production would enhance food security through improved water use. Thus, this study evaluated that the effect of alternate furrow irrigation under different moisture regimes on water use efficiency, growth, yield and yield components of common bean, during 2019 at Alage ATVET College. The experiment was laid out in factorial combination of two factors, following randomized complete block design in split plot arrangement with three blocks consisting twelve treatments; four irrigation levels (100% ETc (I 0 ), 80% ETc (I 1 ) 60% ETc (I 2 ) and 40% ETc (I 3) as the main plot and three irrigation methods (fixed alternate furrow irrigation (FAFI), variable alternate furrow irrigation (VAFI) and conventional furrow irrigation (CFI)) as the sub plot. This experiment showed that deficit irrigation (DI) and AFI significantly (P<0.01) affected days to physiological maturity, No of nodules plant -1 , grain yield, CWUE and IWUE. DI also significantly (P<0.05) influenced days to 50% flowering, stand count, plant height, No of branch, shoot dry weight, nodule dry weight, No of pods plant -1 , No of seeds pod -1 , pod length, 100-seed weight and HI. The interaction effect of DI and AFI also significantly (P<0.05) influenced the biological yield. Maximum (5.16 t ha -1 ) and minimum (3.38 t ha -1 ) biological yield was recorded at I0 and I 3 respectively with combination of FAFI and CFI, in that order. The highest grain yield was obtained under I 0 (2.45 t ha -1 ) and the lowest (1.34 t ha -1 ) was at I 3 . On the AFI, the maximum grain yield (2.11 t ha -1 ) was obtained under FAFI and the minimum (1.78 t ha -1 ) was under CFI. The uppermost CWUE (1.03 kg m -3 ) was recorded at I 3 followed by I 2 (0.92 kg m -3 ) and the smallest was at I0 (0.70 kg m -3 ) followed by I1 (0.77 kg m -3 ). The maximum CWUE (0.92 kg m -3 ) was recorded under FAFI followed by VAFI (0.86 kg m -3 ) and CFI (0.79 kg m -3 ). The partial budget analysis showed that I 0 , I 1 and I 2 gave marginal rate of return above the acceptable threshold value with additional investment advantages for the later. However, there was significant yield difference between I 0 and I 1 ; farmers can save 20% of the irrigation water in the expenditure of the reduced yield (0.33 ton ha -1 ). The highest net benefit was obtained from FAFI, thus the farmers option allows for FAFI at which high yield was recorded. Generally this analysis indicates that farmers at study area and related agro-ecology can use I 0 (100% ETc) in order to maximize their income from increased investment, but if there is lack of adequate irrigation water they can use I 1 (80% ETc) in order to save and use irrigation water more economically.