Restoration of soil quality and improvement of physicochemical properties through grazing exclusion in arid and semi-arid rangelands

Abstract

Soil effect is pivotal in shaping vegetation distribution and has an indirect impact on animals through its influence on the plants they feed on, based on their position in the food web within their respective ecosystems. Vegetation degradation directly affects soil physicochemical properties and fertility. In North African rangelands, this degradation results from anthropogenic activities, particularly overgrazing and random plowing coupled with extended drought periods. While degraded vegetation can be restored in a few years, soil recovery takes several decades. Although the current understanding of the impact of soil degradation on vegetation and animals is established, there is a significant research gap regarding the long-term effectiveness of grazing management practices, especially in arid and semi-arid regions, where challenges related to climate change and drought have been increasing, particularly in the last decade of this century. This study aimed to assess the long-term effectiveness of grazing exclusion on soil properties and surface elements in Halfa steppes (Macrochloa tenacissima (L.) Kunth syn. Stipa tenacissima L.) located in arid and semi-arid regions of Algeria. Soil properties and ground surface conditions were sampled and investigated in 30 randomly selected sites with 15 located in managed steppes with grazing excluded (GE) and 15 in rangelands open to continuous free grazing (FG). Pedological analyses included detailed measurements of soil particle size distribution, moisture content, pH, electrical conductivity, total and active calcium carbonate, carbon content, and organic matter. Each soil sample weighed 1 kg, collected from a depth of 0–30 cm. This depth was chosen as it represented the topsoil layer, which is most affected by environmental and anthropogenic factors. The results showed significant differences between various parameters measured in both types of grazing management schemes of rangelands (GE and FG). Grazing exclusion resulted in a substantial increase in soil moisture (52 %) and clay content (37.53 %), while salinity decreased by 15.52 %. Furthermore, sand content decreased by 10 %, coarse elements by 51.32 %, and bare soil by 57.3 %. These findings underscore that grazing exclusion is an effective strategy for managing and restoring degraded arid and semi-arid grasslands. We recommend implementing grazing exclusion practices as a cost-effective means to rejuvenate indigenous species and combat desertification and man-made environmental degradation.

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