Evaluation of deficit irrigation and irrigation intervals on banana water use efficiency in Kisii, Kenya

Abstract

Water is a scarce natural resource with no known replacement. lnsufficient precipitation in arid and semi-arid regions of East Africa contribute to less water available to crops. Appropriate management ofagricultural water is ofutmost importance This study evaluated the effects ofthree irrigation levels (IL) and three irrigation intervals (ll) on the vegetative growth and yield of East Africa Highland Banana (Musa spp., AAA-EAHB), cv Ng‘ombe. Banana plantlets were planted in a rain-shelter and laid out in a randomized complete block design (RCBD). Levels of water applications were l00%, 90% and 80% of evapotranspiration while 4, 6 and 8 days were used as irrigation intervals to develop treatment combinations noted as IL80.D4, lL90.D4, ILl00.D4, lL80.D6, lL90.D6. ll.l00.D6, lL8O_D8, lL9O.D8 and ll.l00.D8. Based on crop, soil and climate data ofthe study area, CROPWAT 8.0 model was calibrated and used to calculate irrigation water requirements. Local Climate Estimator software of F AO (New_LocClim) was used to provide approximations of climatic conditions because actual data required were not available. Crop data collected over 18 months were subjected to analysis of variance (ANOVA) using the general linear model (GLM) procedure of SAS at 0.05 significance level. Deficit irrigation and irrigation intervals had a significant effect on some important growth parameters and yield of banana. Those parameters include pseudostein girth, plant height, leaf area and distance between leaves. Yield and most of those parameters were not significantly different at Il.l00,D4 and lL90.D4. Calculated irrigation water productivity (IWP) was superior at lL9O.D4 treatment with 6.2 kgm‘ ‘. Developed regression models revealed that pseudostem girth at all growth stages was a good parameter to predict banana yield. CROPWAT 8.0 model's estimation ofthe yield of East Africa highland Banana group at various levels of irrigation and irrigation intervals. Deficit irrigation implemented through short irrigatiowinteivals on banana is an efficient way of saving water without affecting the growth and yield. The findings of this study will contribute to increased water use efficiency, especially in areas with water shortages, like arid and semi~arid regions.