Impact of grazing around a watering point on soil status of a semi‐arid rangeland in Ethiopia

Abstract

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.

Variation in vegetation structure and soil properties related to land use history of old-growth and secondary tropical dry forests in northwestern Mexico

“…It also induces critical changes to soil chemical properties such as pH, cation exchange capacity (CEC) and organic carbon in a direction depending on several factors, being important soil mineralogy and land use history (Gebremeskel and Pieterse, 2006).…”

The State of Soil Degradation in Sub-Saharan Africa: Baselines, Trajectories, and Solutions

“…Extensive research has been conducted into the broader frameworks of integrated soil fertility management [130][131][132][133][134][135][136][137], conservation agriculture [138][139][140][141][142][143], erosion control [144][145][146][147][148], and improved grazing management [149][150][151]. There is also a wealth of information on the benefits of specific practices such as short legume rotations (improved fallows) [152][153][154][155][156][157][158], agroforestry systems [159][160][161][162][163][164][165], and no-till systems [166][167][168][169][170].…”

Isotopic fractionation induced by a surface effect influences the estimation of the hydrological process of topsoil

“…Stable isotope compositions of oxygen and hydrogen (δ 18 O and δ 2 H) in soil water are eco‐friendly indicators for water‐use strategies in plants, water transport, and evaporation (Engda et al, 2016; Fiipovic et al, 2014; Gebremeskel & Pieterse, 2007; He et al, 2017; Sprenger et al, 2016). However, a large spatial heterogeneity of the isotopic signal (Thomas et al, 2013; Yang et al, 2016) influenced by soil properties was detected, which hinders additional applications of isotopes in water.…”