Effect of in-situ Soil Moisture Conservation Measures on Growth Parameters and Yield of Rain-fed Sorghum in Gash Barka, Lowlands of Eritrea

Abstract

Background: Rainfall variability and limited soil-moisture availability are major constraints to rain-fed crop production in the semi-arid lowlands of Eritrea. Improving in-situ soil moisture conservation is therefore important for enhancing sorghum productivity and water-use efficiency under these water-limited conditions. Aims: The study aims to evaluate the effect of selected in situ soil moisture conservation technologies on the growth parameters and yield of rain-fed sorghum in the lowlands of Gash Barka, Eritrea. Study Design: Randomised complete block design (RCBD) with five treatments and three replications. Place and Duration of Study: Aklelet village, Goluj sub-region, Gash Barka, Eritrea, during the 2024 and 2025 seasons. Methodology: Fanya juu terraces, tied ridge, semi-circular bund, mulching at 10 t ha−1, and a farmers’ practice control were tested on plots of 8.4 m × 6 m (50.4 m2). Sorghum ICSV 111 IN was sown at 12 kg ha−1 at 0.70 m × 0.25 m spacing. Growth and yield parameters and soil moisture at 0–20, 20–40, and 40–60 cm were recorded. Rainfall was recorded throughout the growing seasons to calculate water use, and water use efficiency (WUE) was calculated as grain yield divided by seasonal crop water use. Analysis of variance was performed using GenStat 18th edition, with means separated by Fisher’s least significant difference (LSD) at P = 0.05. Results: All the structures significantly improved growth and yield over the control in both seasons. Mulching recorded the maximum grain yield in both seasons (4.30 and 4.53 t ha−1), representing increases of 57.34% and 81.32%, respectively, followed by tied ridge (52.47% and 76.00%). WUE increased from 6.27 to 12.50 kg ha−1 mm−1 (+99.4%) in 2024 and from 6.77 to 15.10 kg ha−1 mm−1 (+123.0%) in 2025 under mulching, and by 89.8% and 109.7% under tied ridge. Conclusion: Although all the structures had a significant effect on sorghum growth and yield, mulching and tied ridge were the most effective and are recommended for Vertisols of the Gash Barka lowlands. Since these findings are derived from two seasons at one site, multi-location testing is required before wider extrapolation.