Abstract:
The soil moisture was the most limiting factors for crop growth especially in low land, aired or semi-aired area due to high evaporation and water scarcity. This experiment was conducted at Woleh irrigation scheme in Wag-himra zone; northern, Ethiopian in the 2023/24 irrigation season, to investigate the effect of deficit irrigation and mulch on water productivity and yield of maize under raised bed planting method. The experiment was arranged in a split plot using a randomized complete block design with three replications with eight treatments: conventional ridge sowing and furrow irrigated raised bed planting with three irrigation application levels (100%, 75%, and 50% of ETc). Pearl millet straw (6t ha−1) was applied as mulch. The test crop was an improved maize variety, BH-546. It was planted in two main plots, one with straw mulch and one without mulch. The spacing between the main plot, subplot, and blocks are 2m, 1m, and 1.5m respectively. The plot size was 3.75m x 3m for maize crop in Conventional Ridge Sowing on spacing between ridge and plant were 75cm and 25 respectively and furrow irrigated raised bed planting 60cm for bed and 30cm for furrow and 45cm is for between row and 25cm between plants. The amount of irrigation water applied was calculated using the CROPWAT8.0 model by using the required input data: crop, soil and climate data. The results clearly showed that the furrow irrigated raised bed sowing method with 100% ETc level and mulch produced the maximum grain yield (6.0t ha−1) and above-ground biomass (28.93t ha−1) comparable to the Furrow irrigated raised bed planting 75% ETc (5.87t ha−1 and 27.33t ha−1), respectively. However, the Furrow irrigated raised bed planting 75% ETc with mulch provided 24% and 28% water savings for both crop and biomass water productivity, respectively, compared to the Furrow irrigated raised bed planting 100% ETc with mulch. Additionally, the Furrow irrigated raised bed planting 75% ETc with mulch saved 75% of water and increased yield by 32% compared to conventional ridge sowing. These results confirmed that Furrow irrigated raised bed planting at 75% ETc with mulch improves yield and water productivity while saving water with minimal yield reduction.
Keywords: Raised bed, mulch, planting method, crop and water productivity, and Pearl millet straw