6 pp. / Originally published 09/2000. / The objectives of this article are to provide an overview of the major grazing systems that have been used on rangelands in the western U. S. and Canada, to summarize the conditions under which they may be applicable, and to highlight examples from the southwestern U. S. when relevant. Revised 12/2014. Originally published 09/2000.

The study was conducted in the Eastern Kalahari sandveld of Botswana on a shrub savanna vegetation type dominated by Terminalia sericea / Boscia albitrunca / Grewia flava and Dichrostachys cinerea woodland. It was initiated in an attempt to determine the impact of livestock grazing within piospheres on soil nutrients, range condition and the influence of season on forage quality and diet composition of livestock. The study was centered around the water points and conducted on both free range grazing and controlled conditions. Measurements on soil and vegetation attributes were recorded at particular points along the transects from the water point. Vegetation and livestock diets were measured seasonally over a period of two years. Chemical analyses of soil revealed the low background fertility of the Kalahari sandveld. The impact of dung and urine on soil chemistry was localized in the area immediate to the vicinity of the water point. Phosphorus, pH and cation exchange capacity were the most responsive attributes to variation along the transect from the water point. High livestock units carried at any particular borehole had an influence on the level of soil nutrient status. Management plans should aim at a more even spread of nutrients by improving the distribution of water points. The zonation of vegetation along the transect from water point reflected the type of management, indicating different class of range condition which can be used in range evaluation and planning. Heavy grazing pressure and trampling in the vicinity of the water point kills sensitive perennial grasses resulting in a zone dominated by annual plants. High amount of available biomass were recorded during summer and autumn and low biomass occurred in spring. The 3 - paddock system produced less biomass compared to other systems, while biomass of palatable species was favored by the 9 - paddock system. Forage utilization was higher following drought years, when grazing pressure was concentrated on reduced forage availability. Utilization of forage was greatest in spring and lowest in summer. Utilization along the transect from water did not taper off until after 4000m from the water point in the free range grazing situation suggesting that forage availability was limiting factor, while in the controlled conditions the influence of grazing tapered off at 1200m. Piosphere size as determined by the distance livestock can travel was greater in the free range grazing management area than in the controlled management conditions. Canopy volumes and leaf dry mass values reflect quantitative variations in the contribution of relatively small number of woody species. In general, both leaf volume and leaf mass decrease with the increase in distance from water due to the reduced plant density. Grewia flava and D. cinerea contributed substantially to the total leaf dry mass within the height below 2m. Leaf dry mass above 2m was largely contributed by Acacia gerrardii, T. sericea and B. albitrunca. Woody species diversity increased with the increase in distance from the water point. High density of G. flava was concentrated to the immediate vicinity of the water points, while species such as Bauhinia petersiana and Croton gratissimus occurred only at further distances from water. There was no clear pattern in the density distribution of D. cinerea along the transect from the water point. Plants exhibit variations in the concentration of nutrients between species and season. High levels of crude protein, phosphorus and low crude fibre content occurred in summer for most species and the opposite was observed during winter or spring. Crude protein and phosphorus during dry periods were believed to be the limiting nutrients in maintaining nutritional quality in grazing animals. Mature forage generally is deficient, and may require supplementation of crude protein or phosphorus. Crude protein, phosphorus and crude fibre were not influenced by the grazing systems. The nutrient enrichment through cattle dung and urine in the vicinity of the water point was reflected in the forage nutrient content. The micro - histological technique proved to be a useful tool for estimating the botanical composition of livestock diets. The technique, however, under-estimates the forbs in the diet of livestock. Diets of cattle were dominated by grasses all year round with a high proportion of woody plants occurred during the spring when available herbaceous biomass was low. Diet of goats was 72% and 82% browse in summer and spring, respectively. Competition for herbaceous plants was high between cattle and sheep. Seasonal species diversity was high in summer and lowest in spring. Goats are more diverse in their diets compared to cattle or sheep which have a strong similarity in their diets. / Dissertation (PhD(Plant Production and Soil Science: Pasture Science))--University of Pretoria, 2002. / Plant Production and Soil Science / unrestricted

Dairy grazing systems have been promoted as an environmentally friendly alternative to concentrated animal feeding operations (CAFOs). However, questions remain regarding the amount of phosphorus (P) loss from pasture-based dairies. Therefore, the goal of this study was to quantify P losses via runoff from grazing dairy systems and CAFO hay production. Four land use treatments were simulated on runoff release plots planted in two forage treatments. Land use treatments were management intensive grazing (MIG) and CAFO hay production to which manure was applied; grazing and CAFO hay production without manure application served as controls. The forage treatments were orchardgrass (Dactylis glomerata) and broad-leafed forage (buckhorn plantain [Plantago lanceolata], red clover [Trifolium pretense], and alfalfa [Medicago sativa]). The four land use treatments and two forage treatments had four replications for a total of 32 (4 land use treatments e n2 forage treatments e n ¤ nreplications) runoff release plots. Thirty minutes of runoff was collected from each runoff release plot during six rainfall simulation series. Grab samples of runoff were collected and analyzed for dissolved reactive phosphorus, total phosphorus, and total suspended solids. Particulate P (PP) was determined indirectly by subtracting dissolved reactive P (DRP) from total P (TP). No distinction was observed between DRP concentrations from simulated MIG plots and simulated CAFO plots for the duration of the study. However, a clear divergence of TP concentrations from CAFO hay plots with manure from all other land uses was observed during simulation series 1. DRP concentrations for all land uses were fairly consistent for the duration of the study with the exception of simulation series 2. All land uses had DRP concentrations that would be considered of concern (> 1.0 ppm DRP) by the US-EPA during simulation series 4 and 5. The elevated TP concentrations and mass losses from CAFO hay plots with manure were primarily due to PP losses. Thus, it was concluded that MIG has less potential for P loss than CAFO hay production. Broad-leafed forage had significantly higher DRP, PP, and TP losses than orchardgrass on CAFO hay with manure. However, no significant difference was found between forage types on MIG plots. Thus, either forage could be planted in grazing land without a significant difference in P losses. / Master of Science

Rotational grazing is being promoted by some land managers, government agencies, and conservation groups as superior to season-long grazing for improving pasture and cattle production, and for grassland bird conservation; however, the assumed benefits have not been comprehensively studied. In 2011 and 2012, I examined the effects of twice-over rotational grazing on the nesting success of grassland songbirds in southwestern Manitoba, Canada. I monitored nesting attempts and collected structural vegetation data for five species of obligate grassland bird (n=110) and one shrub-nesting species (n=41). Nesting analyses were conducted using logistic exposure models. Twice-over grazing had a significantly negative effect on the nesting success of the ground nesting species, including Savannah sparrows (Passerculus sandwichensis). Grazing system did not have an effect on vegetation structure. The results are consistent with other rotational grazing studies, and suggest that twice-over rotational grazing does not benefit grassland songbirds in mixed-grass prairie habitats. / October 2016

Reed canarygrass (Phalaris arundinacea) is a grass species that can dominate wet meadow plant communities. This study investigated if grazing by cattle on restored wet meadows suppresses reed canarygrass, thereby promoting the restored plant community. This study was conducted at two locations in northwest Minnesota. Management practices used were a patch-burn grazing treatment and a four-pasture high intensity-short duration grazing rotation. A pretreatment survey was conducted before grazing followed by annual surveys every five years after grazing. Both treatments reduced reed canarygrass canopy cover by 49 percent compared to non-grazed control sites. Grazed patches were moving towards a Carex dominated community. The community not invaded with reed canarygrass had similar native species richness at the end of the experiment in the rotational grazing treatment, and improved plant richness in the patch-burn grazing treatment. This study demonstrates grazing reduces cover of reed canarygrass, while maintaining or increasing native plant species richness.

The objectives of this dissertation were to identify soil and vegetation changes due to grazing by livestock and to develop guidelines for monitoring the impact of livestock in the Sahelian zone of Africa. The study was conducted in eastern Senegal during 1983 to 1985. The basic methodology was a study of the process of degradation (retrogression) through the collection of data on soils and vegetation along a gradient of increasing livestock pressure. Two gradients were selected along piospheres. Each gradient was placed on a range site that had homogeneous state factors (climate, geology, and rainfall). The results show that the changes in the soil were confined to the top soil horizon. There was a negative correlation between livestock pressure and factors such as infiltration, percent nitrogen, and percent carbon, and a positive correlation between livestock pressure and the factors of bulk density, and phosphorous content. Changes in the vegetation community were dependent on the range site. On the sandy site, there was a linear, negative correlation between livestock pressure and the factors of plant density, plant cover and biomass. On the loamy range site, the changes in these factors along the gradient had a 2nd or 3rd order polynomial relationship. The effects of bush fires and short term droughts on the vegetation were also studied. Drought, in particular, has an impact that is similar to that of livestock pressure, and may compound the results. Multiple regression analysis and a Twinspan ordination program were used to select parameters and plant species that were highly correlated with the gradient, and could act as indicators of each stage of degradation. These indicators can be used to monitor the impact of livestock on rangelands. General parameters, such as total plant density, are less sensitive to drought-induced changes than the composition of indicator species, but the latter are easier to monitor. Both types of indicators can form the basis for a monitoring methodology that can be used in Africa at three management levels: the individual herder, extension agents and regional branches of the division concerned with rangelands, and policy makers at the ministerial level.

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