Investigation of Moisture Collection Structures and Introduction of Resistant Tree Species in the Semi-Arid Slopes of Tigray, Ethiopia

Vegetation cover degradation is a serious problem in low-rainfall areas of Ethiopia. A field experiment was carried out for three years on two degraded hillsides in Kilte Awlaelo district, Tigray, Ethiopia. The objective was to evaluate the effect of moisture harvesting structures on the survival and growth of tree seedlings. The treatments were micro basin, micro trench, eyebrow basin, and conventional pit as moisture harvesting structures combined with three multi-purpose tree seedlings, namely, Schinus molle, Grevillea robusta, and Olea europaea. The set-up was a split-plot design with three replications. Seedling survival, plant height, and collar diameter data were collected. The collected data were analyzed using GenStat 16 edition software by general liner model. Statistically significant differences between and among treatment means were assessed using the least significant difference (LSD) at the 5% level of significance. The results in the main effect showed eyebrow basin > micro basin > micro trench > conventional pit in the upper site, and micro basin > eyebrow basin > micro trench > conventional pit in the lower site in their order of level of significance in enhancing the seedlings survival and growth performance. The interaction effects also showed Schinus molle backed with an eyebrow and micro-basin in the above structure pit position had the highest survival rate and growth performance. Hence, the eyebrow basin and micro basin as moisture harvesting structures planted with Schinus molle tree species at the above pit position should be demonstrated and scaled up in moisture-stressed areas of Kilte Awlaelo district.