Supplementary irrigation for managing the impact of terminal dry spells on the productivity of rainfed rice (Oryza sativa L.) in Fogera Plain, Ethiopia

Tesfaye Molla; Kindie Tesfaye; Firew Mekbib; Tamado Tana; Tilahun Taddesse

doi:10.1016/j.heliyon.2021.e06703

Supplementary irrigation for managing the impact of terminal dry spells on the productivity of rainfed rice (Oryza sativa L.) in Fogera Plain, Ethiopia

Heliyon. 2021 Apr 10;7(4):e06703. doi: 10.1016/j.heliyon.2021.e06703. eCollection 2021 Apr.

Authors

Tesfaye Molla¹, Kindie Tesfaye², Firew Mekbib³, Tamado Tana⁴, Tilahun Taddesse⁵

Affiliations

¹ Department of Plant Science, Debre Tabour University, Ethiopia.
² International Maize and Wheat Improvement Centre (CIMMYT), Ethiopia.
³ School of Plant Sciences, Haramaya University, Ethiopia.
⁴ Department of Crop Production, Faculty of Agriculture, University of Eswatini, Eswatini.
⁵ Ethiopian Institute of Agricultural Research (EIAR), Fogera, Ethiopia.

Abstract

A terminal dry spell is one of the main limiting factors for rice productions. Therefore, this study was conducted to assess the effect of supplemental irrigation for managing the impact of terminal dry spells on the productivity of different rice varieties grown under rainfed conditions in the Fogera Plain. The experiment was designed in a split-plot design with water regimes as main plot factors and rice varieties as a subplot factor with three replications. The water regimes were: dry planted rainfed rice (farmers practice) (FP), transplanted but not irrigated (IWOI), transplanted and irrigated to saturation (SAT), transplanted and ponding to 1 cm water (PD1), and transplanted and ponding to 3 cm water (PD2). The rice varieties were: X-Jigna (V1), Edget (V2), Hiber (V3), Fogera-1 (V4), and Nerica-4 (V5). The combined effect of PD2 with V1 had the highest grain yield (t/ha) (4.35 t/ha) while FP with V3 had the lowest grain yield (2.12 t/ha). The highest (205%) relative grain yield was obtained when V1 was grown under PD2 followed by V4 under PD2 (199%) and V5 under PD2 (192%) compared to FP with V3. Irrigation water productivity (WP_IR) varied between water regimes x varieties from as low as 1.84kg grain mm^-1ha^-1 for V3 in FP to as high as the yield of 3.07kg grain mm^-1ha^-1 for V1 in PD2. The highest and lowest net benefits were recorded for V1 grown under PD2 (65, 550 ETB) and for V3 grown under TWOI (33, 500 ETB ha^-1), respectively. Hence, the combined application of 3 cm ponding depth (PD2) with X-Jigna (V1) and 1cm ponding depth with Fogera-1 (V4) rice varieties could be suggested as effective terminal stress management to increase the yield and profitability of rainfed rice in the Fogera Plain and similar agro-ecologies.

Keywords: Dry spells; Irrigation water productivity; Supplemental irrigation.