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Smallholder farmers in Tigray have been growing Rhamnus prinoides trees/shrubs with annual crops in rain-fed farmlands. Although this agroforestry system is widely practiced, there are no sufficient scientific reports on its profitability and financial returns. The objective of this research was to analyze the financial profitability and relative financial advantages of R. prinoid-based agroforestry compared to monocropping practices, in eastern Tigray. Data were collected using a structured questionnaire from 123 randomly selected households who practiced R. prinoides-based agroforestry. To address the objective, we estimated the net present values (NPV), Annuity values, and benefit to cost ratio (BCR) on per hectare basis. The annuity and BCR of agroforestry were compared with those of adjacent monoculture farms of the associated crop components in agroforestry. The land equivalent ratios (LER) of the agroforestry were calculated and compared with sole crops. The NPV and BCR of the agroforestry were 5.6 and nearly fourfold higher than that of the monocropping, respectively. Similarly, the R. prinoides-based agroforestry LER was 0.33–1.36% higher as compared to monocultures. Stocking density and age of agroforestry affected the financial return from R. prinoides-based agroforestry. We concluded that R. prinoides-based agroforestry has superior financial performance over monocrops and is financially less risky. Therefore, the adoption of R. prinoides-based agroforestry practices is a viable option for smallholder farmers to maximize net returns from their rain-fed farmlands and resource inputs. [ABSTRACT FROM AUTHOR]

The conversion of natural lands to agricultural uses is a significant threat to soil biodiversity. Within agriculture, monoculture based systems are the most common which often result in low biodiversity because they impact the abundance, diversity, and composition of soil macrofauna (SMF). The objective of this paper was to analyze SMF abundance and diversity across different agroforestry practices (AFP) in the drylands of southern Ethiopia. The soil monolith and soil samples were collected from homegarden, cropland, woodlot, and trees on soil and water conservation based AFP using the standard Tropical Soil Biology and Fertility Institute manual, and the identification was done based on morphological characteristics and standard identification keys. The abundance, occurrence, and community composition of SMF were significantly different across the different AFPs (P < 0.05). In this study, 378 SMF belonging to 13 families, including unnamed were identified. The soil ecosystem of AFP was dominated by earthworms (relative abundance = 0.43), followed by termites (relative abundance = 0.12). The homegarden AFP type had a significantly higher number of SMF occurrence index of 46.03 (174), followed by woodlot, 26.72 (101) practices, and the lowest was recorded under cropland, 12.70 (48). The abundance, diversity, richness, and similarity of SMF were significantly related to soil total nitrogen and organic carbon. Phosphorus and pH were significantly related to the abundance and richness of SMF. The homegarden and woodlot AFP types were suitable for SMF biodiversity conservation. [ABSTRACT FROM AUTHOR]

Water availability is the main challenge for the growth and development of woody species in drylands. Application of biochar under deficit irrigation can enhance seedling growth in arid regions. The growth of commercial woody species seedlings was monitored for approximately two years using the combined effect of biochar and deficit irrigation treatments. Biochar was applied to the plantation pits during plantation at a rate of 38 g kg−1 of soil. The applied deficit irrigation per season covered 60% (459 mm) and 35% (459 mm) of the dry season crop evapotranspiration for Citrus sinensis and Yushinia alpina, respectively. We found statistically clear effects of biochar and deficit irrigation on the growth of both species with combined application. Compared to control treatment, the combined application of biochar and deficit irrigation significantly (P < 0.05) increased new culms of Y. alpina by 44%. Moreover, the combined application of biochar and deficit irrigation significantly (P < 0.05) affected the height and diameter relative growth rates (RGRs) of both species by enhancing soil moisture and which in turn increased the photosynthesis and transpiration rates of the species. Compared to Y. alpina, C. sinensis had significantly (P < 0.05) higher height and diameter RGRs and higher transpiration rate. The maximum height RGRs of Y. alpina (0.142) and C. sinensis (0.108 cm month−1) were attained at the end of the rainy season. The highest and significant increment (266.5%) of biomass of Y. alpina was recorded in the plants subjected to combined application of biochar and deficit irrigation However, we could not confirm a significant effect of B alone on the growth parameters of the species. Hence, the integration of biochar and deficit irrigation would be essential for the successful establishment of C. sinensis and Y. alpina seedlings in farmlands of dried region. [ABSTRACT FROM AUTHOR]

Bauhinia thonningii is a woody leguminous tree species, which is endowed with enormous soil improvement, medicinal, nutritional, and socio-ecological benefits in African. The current study was carried out to systematically review and document findings on the multiple benefits of B. thonningii and thereby identify gaps and opportunities for further comprehensive studies. A systematic and manual search was conducted to retrieve relevant articles published from 1974 to June 2021. Electronic databases of PubMed (Medline), Google Scholar, and grey literature were employed to access the studies. Accordingly, 100 articles and 2 thesis papers were finally included in this study. The study shows B. thonningii tree species improve soil fertility and its abundant litter accumulated from the leaves of B. thonningii trees contributed to increased organic carbon and total nitrogen content. The plant parts are used in several traditional medicine to treat different human and animal ailments. The pods and seeds of the plant contained a lot of important nutrients and nutritional value, beneficial to human as well as animal health. The plant plays a key role in biomass production and carbon sequestration potential. Owing to its multiple benefits, there is an urgent need to facilitate the scaling-up of the use of the tree by using various approaches. The findings will serve as a useful reference for further in depth investigations on the multifunctional uses of the plant across different ecozone as well as supporting the scale up of the benefits of the species. [ABSTRACT FROM AUTHOR]

Farmer Managed Natural Regeneration (FMNR) is a rapid, low cost and easily replicated approach to restore and improve degraded agricultural, forest and pasture lands. The study was conducted in low (500–1500 m.a.s.l) and mid (1500–2300 m.a.s.l) altitude agro-ecologies of Tigray region assessing farmer's perception and reasons to practice FMNR. Purposive sampling was used to select three peasant associations (PA's) from each agro-ecology. Simple random sampling was used to select respondents from household heads practicing FMNR. There were 15 respondents from each PA. Total respondents used for the study in both agro-ecologies were 90. All the data required for the study was collected through in-depth household survey and group discussions. Forty two percent (42.2%) of the respondents had 21–30 years of FMNR experience. Seventeen percent of the respondents with FMNR experience were from lowland and 26% were from mid land agro-ecology. FMNR has been practiced for more than two decades in the study areas. In both low and midland agro-ecologies, motivation of the respondents to practice FMNR was the training received from expert's (37.1%) and neighbors' success (29.2%). In the lowland, respondent's main purpose to practice FMNR was fuel wood and fruit collection (49%) while in the midland the objectives were for fuel wood (50%), soil conservation (47%) and fodder (47%). FMNR has enormous importance in the livelihoods of the rural people especially in providing fuel wood, food/fruits, construction materials and farm equipment. [ABSTRACT FROM AUTHOR]

Acacia polyacantha is a fast growing indigenous tree legume that can be integrated with crops as parkland agroforestry system. Farmers keep Acacia polyacantha on their farmlands mainly for fuel wood, animal fodder, farm tools and construction. However, quantitative information on the effect of Acacia polyacantha on soil fertility improvement and socioeconomic benefits is lacking. The effect of Acacia polyacantha on soil fertility and its contribution to household income was evaluated in La'ilay Adiyabo district, northern Ethiopia. At three radii distances, 36 soil samples were collected from two soil depths from 24 trees in cultivated and uncultivated land using a 3 × 2 × 2 × 3 factorial arrangement in randomized complete block design (RCBD) replicated three times. The effect of planting Acacia polyacantha trees on household income was estimated using Ordinary Least Squares based on data collected from a sample of 120 randomly selected farm households. Total N, OC, OM, CEC and exchangeable K levels were significantly higher under the canopies of Acacia polyacantha than outside (p < 0.05). The nutrient levels decreased significantly with increasing soil depth. Planting Acacia polyacantha trees was found to positively and significantly influence household income, in which case the aggregated monetary value of the different products from Acacia polyacantha contributed 13.7% to total household income, which is significant. However, land size was also found to be crucial; and the role that Acacia polyacantha trees play can be further increased through efficient use and management of agroforestry land. [ABSTRACT FROM AUTHOR]

Woody diversity and carbon stock estimation of land use types have critical role for the successful implementation of climate change mitigation and adaptation strategies. This study investigated relationships between woody species diversity and carbon stock in different land use types. Three land use types (area exclosure, homestead agroforestry and woodlot) were selected in the Gergera watershed, Tigray, Ethiopia. A total of 45 sample plots were established using stratified random sampling, 15 plots in each land use types. Vegetation parameters such as diameter at breast height, diameter at stump height, tree height and species type were recorded. Woody species diversity and carbon stocks significantly varied among the land use types. Woody species diversity, species richness and species density were significantly higher in exclosure compared to the other land use types. Mean above-ground woody species carbon stock in woodlot (8.79 ± 7.72) was significantly higher than both in exclosure (2.29 ± 2.73) (p = 0.002) and homestead agroforestry (4.17 ± 4.18) (p = 0.022) and similarly had higher below ground woody species carbon stock than the other two systems. However, there were no significant difference among exclosure and homestead agroforestry in total carbon stock. There were a significant relationship between woody species diversity and carbon stock (R2 = − 0.349, p = 0.019) in each land use types. Land-use change can lead to changes in species diversity and significantly contribute to carbon sequestration. Although, more carbon stock was found in woodlot dominated by Eucalyptus, this would result in water competition and other fast growing trees may be preferable. [ABSTRACT FROM AUTHOR]

The interaction of human land use, steep slopes and erosion has been a serious threat to Ethiopia’s ecosystems. Community’s initiated land rehabilitation programmes such as tree regeneration on farm lands, hill-side planting and exclosures have been established to rejuvenate debilitated lands. To characterize, map out and monitor such transformations, this study was carried out in Zongi, Tigray Region of northern Ethiopia. The study used an integration of remote sensing data, field observations and information from key informants and randomly selected respondents to analyse the land-use/land cover (LULC) changes from 1984 to 2013. Conventional method of supervised image classification was used for landsat image of 2013 while hybrid method of unsupervised and supervised classification was employed for landsat images of 1984 and 1999. The results revealed significant modifications and conversion of LULC types over the multi-dates. Analysis of the 29-year change matrix revealed that 78.5% of the land underwent significant changes in LULC. The major changes to agroforestry land use(LU)types between 1984 and 2013 were conversion of intensively cultivated land to moderately cultivated land (32.1%) and sparsely cultivated land (11.8%). The drivers of changes were linked to the introduction of land rehabilitation initiatives, government consensus (via agricultural extension) with the community, which were complemented by growing awareness of landowners. This study corroborates the necessity of community involvement and participation to improve their land use systems for environmental sustainability and sustainable livelihood. [ABSTRACT FROM AUTHOR]

Integrating agroforestry trees such as Faidherbia albida (F. albida) into cropland improves soil fertility and maintains persistence of associated beneficial microorganisms such as Arbuscular Mycorrhizal Fungi (AMF) that protects crops from striga colonization. Striga hermonthica (striga) is an obligate root hemi-parasitic weed of maize and sorghum, which stunts growth and causes low grain yield. Data on physico-chemical properties of the soil, yield components of sorghum, striga infestation and spore abundance and colonization of AM fungi were collected from underneath and away from the F. albida canopy. The experiment was composed of four treatments and six replications in a randomized complete block design (RCBD) with 24 plots, each with 15 m2 size. Soil and root samples were also collected from under and outside of the F. albida canopy and sorghum crops. Soil organic matter, total N, available P, CEC, and total K were significantly higher under the F. albida canopy than away from it (P < 0.05). Similarly, yield of sorghum was also significantly higher under the F. albida canopy than away from it (P < 0.05). The highest striga count was recorded away from the F. albida canopy. In contrast, minimal striga infestation was found under and at the periphery of the F. albida canopy. The spore density and colonization of AMF were higher under and at the periphery of the F. albida canopy than away from it (P < 0.05). There was a significant and negative correlation between AMF fungi spore density and colonization, and striga counts at the early stage of sorghum growth. Integrating F. albida into agricultural fields with sorghum crops improves productivity and maintains AM inoculum which may control striga weed infestation. [ABSTRACT FROM AUTHOR]

Tree seedling establishment, survival and growth in dryland areas is greatly impacted by water, land use effects and soil nutrient availability. Arbuscular mycorrhizal fungi (AMF) can have a substantial effect on water and nutrient uptake by seedlings and are affected by nutrient application, water availability and inoculum source. In this study, we examined the effect of AMF inoculation, phosphorus application levels, soil water status, and inoculum source on the growth of Faidherbia albida seedlings. Two greenhouse experiments were conducted on F. albida seedlings: to compare (a) ±AMF inoculation, at three levels of volumetric soil water content (field capacity (FC), 60% of FC and 20% of FC), and three AMF inoculum sources (derived from cultivated land, grazing land and area exclosure); (b) ±AMF inoculation, at four levels of phosphorus application (0, 25, 50 and 100 mg kg−1) and three AMF inoculum sources. Inoculation with AMF, higher soil water and higher P application significantly increased the growth of seedlings (P < 0.05). F. albida seedlings responded positively to increased water levels. The highest growth and AMF colonization of seedlings was recorded under the lowest water stress with AMF inoculum from area exclosure followed by grazing land inoculum source. The lowest growth was recorded under the highest water stress and cultivated land inoculum source. Plant growth and biomass were positively correlated with increased soil P application, however, AMF colonization decreased with increasing P application. Applying P and inoculating F. albida seedlings with indigenous AMF under low water stress enables optimum plant growth improvement in dryland farming systems. [ABSTRACT FROM AUTHOR]

Concerns about sustainable management and conservation of multipurpose trees in their habitat have led to increased number of studies on the ecological characterization of their population. Such knowledge on Faidherbia albida, the most used tree in agroforestry parklands in Ethiopia, is limited. F. albida population was characterized in and compared between two agroforests having different conservation status in Northern Ethiopia. Population structural parameters along with environmental factors and human activities were assessed in 42 randomly installed plots using a transect method. Size class distribution was used to describe and analyze the species long-term population dynamics. Adult density was almost three times higher in Zongi agroforest (19.9 ± 2.9 trees ha) where the species has been conserved and managed for longer time compared to Abraha-atsbeha agroforest (7.9 ± 2.5 trees ha). The same trend was observed for tree morphological parameters which were significantly higher at Zongi than Abraha-atsbeha. However, size class distributions coefficient of skewness and the median diameter indicated a declining and vulnerable population at Zongi and an increasing population at Abraha-atsbeha. Species population characteristics were influenced by environmental factors such as altitude, stone cover, erosion severity, slope, and human-related disturbances including land use, fodder harvesting, distance away from the center of the village and proximity of household to the plots. The study confirms the impact of conservation, environmental factors and human disturbances on shaping F. albida population and recommends the consideration of the trade-offs between them to design effective conservation and management strategies to sustain F. albida agroforests. [ABSTRACT FROM AUTHOR]