Survival and plasticity in Acacia saligna growth across Contrasting management practices and growing niches.

Reforestation and afforestation either through natural regeneration, tree planting or both methods have been globally promoted to motivate ecological restoration of degraded lands and to improve livelihoods. However, moisture stress and infertile soils limit the survival and growth of trees planted for restoration in drier areas. Hence, understanding the factors that determine the restoration success of drylands through tree planting is critical. We conducted a factorial experiment in Tigray, Ethiopia to evaluate the survival, growth performance and biomass of planted seedlings of the multipurpose agroforestry tree species Acacia saligna over 24 months. The treatments were application of watering (W), mulching (M) and compost (C) separately and in combinations (WM, WMC). We established experimental plots on farmland and on a nearby hillside-exclosure to examine the role of planting niches on seedling performance. Seedlings treated with watering, mulching, and compost (WMC) revealed significantly greater height, root collar diameter (RCD), and dry biomass compared to the other treatments. Seedlings planted in farmland showed significantly greater height, RCD, and total dry biomass compared to those planted at the hillside-exclosure. Although the survival rate was slightly higher in farmland, we also found sufficient survival rates in the hillside-exclosures. Therefore, post-planting care and activities including mulching, watering and fertilization are crucial to enhance the survival and growth performance of A. saligna or other tree species so that efforts in reversing land degradation and restoration of drylands will be successful.

Adaptation and growth performance of five avocado cultivars in Ethiopia.

Ethiopia has diverse agroecology with vast areas, suitable for growing subtropical and tropical fruits. Despite this potential, the avocado industry in Ethiopia is still in its infancy. This study assessed the adaptation of five avocado cultivars: Ettinger, Fuerte, Hass, Nabal, and Reed, survival rate, growth performances, fruit yield, and household contributions in Lemo district Ethiopia. The results revealed that there were significant differences in tree growth performance and yield among avocado cultivars (P < 0.05). The highest vegetative growth performance was demonstrated by Nabal, Fuerte, Ettinger, and Hass, while Reed was the lowest. In 2020, Nabal had the highest fruit yield (96 kg tree1), followed by Hass (47 kg tree1), while Fuerte had a relatively low fruit yield (39.43 kg tree1). Due to its larger fruit size, the Nabal was used for sale, while the Hass cultivar, which has a sweet taste, was mainly used for home consumption. The findings demonstrated that significant difference in management practices applied by male and female farmers. Overall, the study concluded that the Nabal, Hass, and Ettinger cultivars had a great potential for fruit production, which could improve smallholder farmers livelihood. As a result, it is necessary to scale up these avocado cultivars in the midland agroecological zone of the country.

Nutritional and ecoclimatic importance of indigenous and naturalized wild edible plant species in Ethiopia.

Wild edible plant species (WEPs) are sources of food, nutrition, and medicine to people. However, often, the nutritional value of WEPs is unknown. This study was conducted to determine proximate and mineral contents of Balanites aegyptiaca, Cordia africana and Ziziphus spina-christi fruit. Fruit samples were collected from 10 trees of each species from Northern and Rift Valley region of Ethiopia. Fruit samples from the same species and district were mixed to form a composite sample, then dried, ground to powder and used for chemical analysis. We found a comparable amount of mean crude protein contents in C. africana and B. aegyptiaca. The fiber content was higher in B. aegyptiaca and Z. spina-christi. Carbohydrate and energy content were higher in Z. spina-christi compared to other study species. We found higher values of calcium in B. aegyptiaca and Z. spina-christi potassium, iron and zinc contents of B. aegyptiaca and C. africana, exceeded the value found in Z. spina-christi by about 50%. Our findings confirmed that the studied food tree species are potential sources of macronutrients and minerals. Therefore, promoting their sustainable use and increasing their abundance on different landscapes through Agroforestry system is critical to improve food availability and landscape resilience to climate change impacts.

Volume estimation models for avocado fruit.

Avocado (Persea americana Mill.) is an important horticultural crop and proved to be a very profitable commercial crop for both local consumption and export. The physical characteristics of fruits are an important factor to determine the quality of fruit produced. On the other hand, estimation of fruit volume is time-consuming and impractical under field conditions. Thus, this study was conducted to devise cultivar-specific and generalized allometric models to analytically and non-destructively determine avocado fruit volume of five wildly distributed avocado cultivars. A significant relationship (P ≤ 0.01) was found between fruit diameter, length, and volume of each cultivar. Our best models (VM2 -for cultivar specific, and VM7-generalized model) has passed all the rigorous cross-validation and performance statistics tests and explained 94%, 92%, 87%, 93%, 94% and 93% of the variations in fruit volume of Ettinger, Fuerte, Hass, Nabal, Reed, and Multiple cultivars, respectively. Our finding revealed that in situations where measurements of volume would be inconvenient, or time-consuming, a reliable volume and yield estimation can be obtained using site- and cultivar-specific allometric equations. Allometric models could also play a significant role in improving data availability on avocado fruit physical appearance which is critical to assess the quality and taste of fresh products influencing the purchase decision of customers. Moreover, such information can also be used as a ripeness index to predict optimum harvest time important for planned marketing. More importantly, the models might assist horticulturists, agronomists, and physiologists to conduct further study on avocado production and productivity through agroforestry landuse system across Ethiopia.

Data on how tree planting and management practices influence tree seedling survival in Kenya and Ethiopia.

Understanding which trees farmers prefer, what determines their survival and enhancing farmer knowledge of tree management is key to increasing tree cover in agricultural landscapes. This article presents data on tree seedling survival under different tree planting and management practices in Kenya and Ethiopia. Data were collected from 1600 households across three Counties in Kenya and 173 households across four Woredas in Ethiopia, using a structured questionnaire which was administered through the Open Data Kit. Data on seedling survival were collected at least six months after tree seedlings were planted. To understand how planting and management practices influence tree planting across the different socioeconomic and biophysical contexts, both household level and individual tree level data were collected. Household level data included socio-economic and biophysical characteristics of the households while tree specific data included when the tree seedling was planted, where it was planted, the management practices employed and whether surviving. The datasets described in this article help understand which options confer the best chance survival for the planted seedlings and in which socio-economic and biophysical contexts they are most successful.