The influence of long-term livestock grazing on the soil status of a semi-arid rangeland was studied along a grazing gradient from a watering point in southern Afar Region of Ethiopia for two seasons. The soil samples were analysed for organic carbon (OC), total nitrogen (N), available phosphorus (P), exchangeable cations (Ca 2+ , Mg 2+ , K + and Na + ), acidity (pH), cation exchange capacity, and particle size distribution (clay, silt and sand). No significant differences (P > 0.05) were observed for particle size distribution, OC, N, P and K contents along the grazing gradient further than 1500 m from the watering point. Ca 2+ and Mg 2+ were found to be dominant cations particularly in the severely degraded area contributing about 74% to the exchangeable cations. The study has also recognized high concentrations of Na + and more than 11% exchangeable sodium percentage. Total exchangeable bases significantly declined (P < 0.05) along the grazing gradient and were indicative of the exchange complex of the soil being saturated with Ca 2+ and Mg 2+ ions. Thus this study concluded that there are soil differences in the grazing gradient caused by impact of grazing, particularly in the severely degraded area. RésuméOn a étudié pendant deux saisons l'influence du pâturage de longue durée par du bétail sur le statut du sol dans une étendue semi aride, le long d'un gradient de pâturage au départ d'un point d'eau dans la région sud des Afars en Ethiopie. Les échantillons de sol ont été analysés pour le carbone organique (OC), l'azote total (N), le phosphore disponible (P), les cations échangeables (Ca 2+ , MG 2+ , K + et Na + ), l'acidité (pH), la capacité d'échanges de cations(CEC) et la distribution par taille des particules (argile, limon et sable). Il n'y avait pas de différence significative (P > 0,05) de la distribution des particules selon la taille, ni du contenu en OC, N, P ni K le long du gradient plus loin que 1.500 m à partir du point d'eau. On a découvert que le calcium 2+ et le Mg 2+ étaient les cations dominants, particulièrement dans la zone gravement dégradée et qu'ils contribuaient pour environ 74% aux cations disponibles. L'étude a aussi repéré de fortes concentrations de Na + et plus de 11% de sodium échangeable (ESP). Les bases échangeables totales (TEB) diminuaient significativement (P > 0,05) le long du gradient de pâturage et étaient indicatives de l'échange complexe du sol saturé en ions Ca 2+ et en Mg 2+ . Cette étude a donc conclu qu'il y a des différences dans le gradient de pâturage, causées par ce pâturage, spécialement dans la zone gravement dégradée.

A study to investigate oversowing of grass species as a restoration strategy in severely degraded rangeland was carried out in the Allaidege rangeland in north-eastern Ethiopia. Locally collected seeds of three grass species (Enteropogon rupestris, Ischaemum afrum and Tragus berteronianus) and imported seeds of three additional species (Cenchrus ciliaris, Chloris gayana and Panicum coloratum) were oversown in a severely degraded area of the rangeland to improve cover and grazing capacity of the rangeland. The effect of combinations of inorganic fertiliser, manure and grass mulch on the dry matter production of the grass species sown at 4 kg ha -1 in strips in a 10 m X 10 m plot was determined. The experiment was a randomised complete block design with eight factorially combined treatment combinations randomly applied and replicated three times. All the sown species showed significant positive responses to the mulch treatment, but not to the other treatments or treatment combinations. Ischaemum afrum and T. berteronianus produced significantly more dry matter (900 kg ha -1 and 800 kg ha -1 , respectively) than the other species. The results emphasised the importance of mulching to restore degraded patches in arid and semi-arid environmental conditions.