Evaluating the Effects of Deficit Irrigation and Mulch Type on Yield and Yield Components of Onion in Fogera, Ethiopia

Abstract

Water scarcity is a challenge for current irrigated agriculture globally. Under these circumstances, new on-farm irrigation management strategies should be established. An experiment was conducted at Fogera in 2021 to evaluate the effects of deficit irrigation (DI) and mulch type on onion yield and yield components. A factorial combination of three levels of DI (100%ETc, 75%ETc, and 50%ETc) and three mulch types No Mulch (NM), White Plastic Mulch (WPM), and Rice Straw Mulch (RSM)) were evaluated in RCBD with three replications. Monthly ETo, ETc, and irrigation scheduling were computed using CROPWAT 8.0 model. These studies showed that the onion yield and yield components were significantly affected by the main and the interaction effects. The maximum average plant heights (PH), leaf heights (LH), and number of leaves per plant (LNP) of 51.7 cm, 38.0cm, and 10.4 respectively, were recorded from 100%ETc whereas the minimum PH, LH, and LNP of 39.5 cm, 29.0cm, and 6.9 were recorded from 50%ETc treatment respectively. The highest average bulb weight (BW), bulb diameter (BD), and bulb height (BH) were 117.9gr, 6.4, and 5.7 cm recorded from 100%ETc treatment respectively. In contrast, the minimum average BW, BD, and BH were 79.9gr, 4.8, and 5.0cm recorded from 50%ETc respectively. The highest PH, LH, and LNP of onions were 51.9cm, 40.6cm, and 10.1 respectively recorded from RSM treatments. In contrast, the minimum PH, LH, and LNP of onions were 41.5cm, 31.1cm, and 7.5 respectively, recorded from WPM treatments. Similarly, the highest mean BW, BH, and BD 106.2gr, 5.8cm, and 6.0cm were obtained from the treatments of RSM respectively. In contrast, the lowest mean BW, BH, and BD 100.7gr, 5.0cm, and 5.3cm were obtained from NM treatments respectively. The interaction effects of DI and mulch showed that the onion yield at 100%ETc with RSM was 7.5% higher than that at 100%ETc with NM and 15.1% higher than the yield at 100%ETc with PM. The highest BW, BH, and BD of the onion 121.8 gr, 6.2, and 6.8 were obtained when the onions received 100%ETc and mulched with RS while the lowest average BW, BH, and BD of the onion were 77.3gr, 4.6cm and 4.1cm were obtained from 50%ETc with NM treatment combination. These results showed that RSM with 75%ETc improves onion yield and yield components.