Article: Spatial Management of Grazing to Enhance Both Livestock Production and Resource Condition: A Scientific Argument
Authors: Norton, Brian E.
Journal: Proceedings of the VIIth International Rangelands Congress
As we have seen, increasing stocking rates can dramatically improve overall operational performance by improving per hectare production, hence increasing total ranch production. In many cases, stocking rates have been increased well beyond expectations.
Norton poses the question: How is range and vegetation condition affected by stocking rate increases? One might suspect that stocking rates increases can be sustained for short periods, but that declining vegetation quality and quantity will eventually result in an overall reduced carrying capacity. Research shows that this is not the case.
As Norton notes, Smoliak (1960) conducted a study in Alberta, Canada and measured a number of vegetation variables “including species composition, plant density, plant cover, forage production, and forage quality…” In the implementation of this research, “he was able to comfortably carry 60% more animals for 7 years under either continuous grazing or a deferred rotation without adverse impacts to the vegetation…”
And again, research conducted in Zimbabwe by Barnes and Denny (1977, 1991) demonstrates that “stocking rate can be substantially increased beyond what is generally recommended as the optimum carrying capacity for the kind of rangeland found near Bulawayo, increased to even double the recommended rate, without imposing adverse impact on the condition of the resource.”
As this paper notes, grazing management under research conditions frequently demonstrates the possibility of increased stocking rates: “Norton cites nine examples from the published literature… in which stocking rates 50% greater (or more) than the recommended district rates were sustained…” This is consistent with anecdotal evidence and monitoring data from commercial operations:
Primary producers claim that some forms of rotational grazing systems allow a substantial in stocking rates above previously recommended levels (an increase of at least 50 or 100% is common) without significant loss of individual animal production, with a concurrent improvement in rangeland condition and much higher gross income margins.
This information is consistent with the results of the Charter Estate Grazing Trials.
The reasons for these improvements are manifold. One potential reason is improved animal nutrition. Although short duration grazing increases grazing pressure, animals are moved rapidly through a paddock and often can only take a single bite of a tiller and “the first bite that a herbivore removes from a particular plant or tiller is arguably more nutritious than subsequent bites from the same part of the plant, and thus diet quality is maintained…”
Vegetation quality is maintained because “the first bite removes only about half of a grass tiller, which is a moderate level of impact, and remaining photosynthetic tissue contributes to the rate of recovery from defoliation.” Additionally, the ability to control utilization, eliminate soil capping, remove standing dead material, and design disturbance has a number of other benefits that are all but impossible to achieve under continuous grazing.
When we begin to combine these insights and research results with careful planning, strong monitoring, and GIS, Holistic Management becomes an extremely attractive option for those managers looking to optimize ranch performance and achieve specifically defined objectives.
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