Impact of grazing system on rangeland condition and grazing capacity in Zimbabwe

Abstract

The influence of different land tenure and rangeland management systems on rangeland condition and livestock grazing capacity in African rangelands is not well documented. A rangeland condition assessment was carried out at 15 sites located in the communal grazing system, small-scale commercial grazing system and the large-scale commercial grazing system in Zimbabwe. Rangeland indicators assessed were: floristic composition, herbaceous biomass yield, shrub stem density and grazing capacity. Grass species composition and forage value were analysed using PROC FREQ procedure of SAS 9.3. Fisher’s exact test was performed to test for independence of the grass variables between grazing systems. A one-way ANOVA was used to test for significant differences (P < 0.05) in floristic composition, shrub stem density, herbaceous biomass yield and grazing capacity among the three grazing systems. It was observed that communal rangelands had significantly high levels of woody species, unpalatable wiry grass species, low biomass yield and were dominated by the invading shrub Helichyrsum kraussii compared with the other rangeland management systems. These results suggest that if control measures are not put in place, livestock production may not be feasible in communal rangelands in the near future because of high levels of rangeland deterioration when compared with the commercially managed rangelands. Furthermore, the observed high stem density of unpalatable woody species and the low grazing capacity of communal rangelands affect livestock production, a primary source of livelihood. This warrants a change in rangeland management system in favour of the rest-rotation grazing system, which is beneficial to both livestock and the range.

Adaptive multi-paddock grazing management reduces diet quality of yearling cattle in shortgrass steppe

“…Although the contribution of different plant functional groups to cattle diets varied widely both within and across years, we did not detect any clear differences in functional group composition between the two grazing treatments that could explain the difference in dietary CP during the first half of the grazing season each year. Rather, cattle foraging-behaviour data indicated that the reduction in diet quality was associated with CARM steers foraging in more linear pathways and moving across shorter distances in each foraging bout, than did TRM steers (Augustine et al 2023), because the 10-fold higher stock density increased inter-animal competition (Popp et al 1997;Rind and Phillips 1999;Gusha et al 2017). In contrast, TRM cattle foraged in pathways with greater tortuosity and moved over a longer distance during each foraging bout (Augustine et al 2023), which suggests that they more selectively consume bites with less standing dead vegetation and more green leaves.…”

Contribution of Soil Type to Quantity and Nutritional Value of Grass Species on the South African Highveld

“…The low proportion of highly palatable grasses observed in Avalon and Clovelly soil types indicates preferential grazing, which if allowed to continue may result in local extinction of these desirable forage species [26]. Gusha et al [47] also stated that the reduction of desirable species may be due to frequent defoliation under continuous grazing systems.…”