Exclusion of grazing animals and tree plantations were among the methods used for the rehabilitation of degraded lands in tropical semiarid areas. Exclosures can foster secondary forest succession by improving soil conditions, attracting seed-dispersal agents and modifying microclimate for understory growth. This paper compares the woody species diversity and soil chemical properties under exclosure with increasing age and grazing land at different slope positions. The study has been conducted in northern Ethiopia from 12 exclosure sites paired each with adjacent grazing land with four treatments replicated three times. In the entire study 216 plots were examined of which 108 were in exclosures and 108 in communal grazing lands.There were four age classes and three slope positions in each of the landuses. Vegetation data were collected using plots measuring 100 m 2 . Soils for physicochemical properties were collected from the four corners and center of 5 × 5m plots which was inside the 10 × 10m plot. A total of 61 woody plant species belonging to 41 families were recorded. Diversity and species richness were higher in the exclosures than in grazing lands. Among exclosures these parameters were higher in exclosures older than 30 years and at the foot of the slope. Grazing lands, the youngest exclosures and upper elevation gradient recorded lower values. Chemical soil properties were significantly higher in the exclosures, among them in the oldest exclosures and at foot elevation (except for P) than these were in the grazing land, the youngest exclosures and upper parts of slopes respectively. Exclosures are instrumental to improve the woody species diversity and soil chemical properties in the drylands.

Agricultural land degradation in Ethiopia leads to an annual loss of roughly 2 million cubic meters of top soil. The relationship between this loss of soil quality and declining agricultural productivity is increasingly threatening rural livelihoods, putting pressure on urban centres as people migrate, as well as on very scarce forest resources on which the agricultural systems eventually depend Attempts to address land degradation have required the government of Ethiopia to fully understand the underlying social and ecological drivers of land degradation. In order to fully develop the knowledge portfolio required to design and implement land rehabilitation measures in remote areas experiencing degradation, an adaptable, robust and credible system of ethno-ecological knowledge representation, analyses and communication is required. This is needed not only to bridge the technological gap between the rural and urban areas but to facilitate the representation and integration of both temporally and spatially explicit historical and 'real time' knowledge, held within rural environments. This paper describes the application of participatory geographic information systems (PGIS) tools and approaches in Tigray, Ethiopia. In this application to generate both current and retrospective information of land use processes, the use of PGIS focuses on methods of knowledge 'capture', representation and communication through the graphic representation of both past and present land uses using rudimentary tools. The information gathered in the process is then transferred into a Geographic Information System, for additional analyses, sharing with scientists and onwards transmission to decision makers and other users in a form which they respect, can understand and reproduce. The practice of PGIS in this setting in Ethiopia has encouraged broad-based participation at community levels, improved within-community communication and provided opportunities for greater social inclusion in development processes.

This study investigated that the effects of cochineal invasion and climate change on cactuspear distribution. Rainfall and temperature were projected to near, mid, and end-century withemission scenarios (RCP4.5 and 8.5) using R-programing language. Average temperature willbe increased by 1.7, 2.3, and 2.6°C in RCP 4.5 and 2, 2.8, and 4°C in RCP 8.5 at 2010-2039,2040-2069, and 2070-2099, respectively, and there will be temporal and spatial rainfallvariation. The cactus pear distribution will be reduced by 13, 0.51, and 27% during mid-centuryof RCP 4.5 and RCP8.5, and RCP8.5 of end-century, consistently. But, it will be increased by0.8% at the end-century of RCP4.5. The impact of climate change in future cactus peardistribution is insignificant. In addition, the probability of cochineal invasion will be increased byabout 72, 74, 62, and 94% by mid and end-century of RCP4.5 and 8.5, respectively. This hasa significant impact on future cactus pear distribution. The combined effect of climate changeand cochineal invasion will affect 72, 78, 63, and 85% of cactus pear distribution by mid andend-century of RCP4.5 and 8.5, respectively. It has a significant impact on future cactus peardistribution. Therefore, the study recommends well-designed management strategies to ensurecactus pear survival.

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Dry areas are vulnerable to climate change and are commonly hit by drought, which makes the inhabitants to rely on food aid. Mushroom cultivation is a profitable agribusiness that can improve the economic and food status of farmers in dry areas as an alternative technology. Research on the effect of substrates on the yield, yield attributes and dietary values of oyster mushroom (Pleurotus ostreatus) was conducted to identify the best substrates. The experiment included 23 treatments with three replications. The substrates were sawdust, rice straw, cottonseed hull & maize cob with 100%, 75%, 50% and 25% combination ratios. The substrates were chopped, moisturized and filled into 40 cm X 60 cm polyethylene bags and sterilized for one hour at 100 o C. The substrates were cooled and inoculated with 75g mushroom spawn, and were kept in a dark place to enhance mycelium growth. The substrates were transferred to a growing room, with full light, lower temperature and higher relative humidity for fructification after mycelium growth was completed. Data on yield attributes, fresh yield and dietary values were collected and analyzed. The fruiting bodies were picked after 22 -35 days of inoculation. The treatments had significant effect on the number of days for mushroom growth, stalk length, pileus diameter and number of fruiting body, fresh yield, biological efficiency and dietary values (P < 0.05). All consumers significantly preferred mushroom grown on 100% maize cob substrate. The 100% cottonseed hull substrate gave the highest profit (133.25US$ 100kg -1 substrate). The study concluded that 100% cottonseed hull substrate was the best substrate for oyster mushroom production at small-scale level. It was also the best nutritive source of substrate for oyster mushroom growth. Mushroom grown on a 100% maize cob substrate was a tasty and protein rich mushroom. Therefore, producers should be encouraged to use this substrate for maximizing the yield, for changing the agricultural wastes into food in the form of mushroom and for improving their livelihood. Oyster mushroom could play a pivotal role in supporting the food self-sufficiency, hence it should be included as a component of food security assurance strategy for the country.