DEFICIT IRRIGATION AND MULCHING EFFECTS ON HOT PEPPER (Capsicum annuum L.) YIELD AND WATER USE EFFICIENCY AT MELKASSA, CENTRAL RIFT VALLEY OF ETHIOPIA

Abstract

The increasing scarcity and competition for irrigation water entails adoption of innovative practices that increase efficient water use. In the context of improving water use efficiency, there is growing interest in deficit irrigation which provides a means of reducing water consumption while minimizing adverse effects on yield. A field experiment was conducted at Melkassa Agricultural Research Centre in the Central Rift Valley of Ethiopia during the 2016/2017 dry season to study the ‘Effects of different deficit irrigation levels and mulching techniques on yield and water use efficiency of hot pepper (Capsicum annuum L., cultivar: Mareko fana) under Melkassa climatic condition. The experimental design of the trial was split plot design in RCBD with three replications, in which deficit irrigation levels (100%ETc, 80%ETc, 70%ETc, 60%ETC and 50%ETc) were used as main plot and the three mulching materials (no mulch, straw and plastic mulch) were used as sub-plot and laid out as treatments in plots of 3.5 m x 3.9 m. The analysis of variance showed that days to 50% flowering, days to 50% maturity, leaf number per plant and mean fruit length were significantly affected (P<0.01) by the main effects of deficit irrigation levels and mulching but deficit irrigation levels and mulching materials did not interact to influence these parameters. However, the interaction effects of deficit irrigation levels and mulching materials significantly (P<0.01) influenced plant height, number of branches per plant, number of fruits per plant, marketable, unmarketable and total yields of the hot pepper. The results revealed that the maximum yield of 2892 kg ha-1 was recorded from 100%ETc with plastic mulch; whereas the minimum yield of 1114 kg ha-1 was recorded from 50%ETc with no mulch. Higher CWUE and IWUE of about 8.48 and 7.63 ha-1 mm-1 was obtained from 70% ETc with plastic mulch respectively. With 70% ETc and plastic mulch the water saved, yield reduction and CWUE were 109.5 mm, 25.10% and 8.48 kg ha-1 mm-1, respectively. Considering the highest water saving, efficiency values and minimum yield reduction, irrigation water application at 70% ETc deficit level and plastic mulch could be considered as optimal irrigation as compared to other deficit treatments. The present study suggests that, in water scarce area, farmers are advised to adopt deficit irrigation level with 70% ETc under plastic mulch. However, if water is not a limiting factor, farmers are advised to apply full irrigation water application under plastic mulch