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Grazing Studies
Investigators: Dr. Brien E. Norton, Dr. John C. Malechek, Matthew K. Barnes, and Motoko Maeno
Objectives
- To determine whether or not the spatial distribution and selectivity of grazing are improved by decreasing pasture size and increasing stocking density.
- To redefine the paradigm of grazing management and explain much of the debate over short duration and management intensive grazing, by demonstrating a basis for improving livestock production through spatial grazing management.
Justification: Practitioners of short duration and management intensive grazing often claim substantial increases in livestock production with simultaneous improvement of rangeland resources. Researchers, however, have found no consistent advantage to rotational grazing in terms of control over the frequency of defoliation. Patch grazing in large, continuously grazed pastures has been identified as a mechanism of range degradation even at low stocking rates, but has generally been ignored or assumed away in grazing trials involving small pastures. If distribution can be improved to the extent that patch grazing is substantially reduced, higher stocking rates will be sustainable and the debate over rotational grazing can be partially explained.
Methods
-Spatial distribution of grazing was compared in paddocks representing stocking densities found in deferred rotation grazing and in 16-, 32-, and 64-pasture rotations, at a constant stocking rate.
-Species selectivity and repeat defoliation within grazing periods were measured with permanently marked plants in each trial.
Products and Status:
-A redefinition of the theory of rotational grazing management, that explains the potential for increased sustainable livestock production. Preliminary results from the first of two grazing seasons indicate that distribution was more even in all trials representing intensive rotational grazing than in deferred rotation pastures.-Master's thesis and journal article on species selectivity (Maeno), Spring 2002.
-Master's thesis and journal article on spatial distribution (Barnes), Spring 2002.
-Presentation to the Utah Section of the Society for Range Management, November 2001.
-Presentation to the Society for Range Management, February 2002.
-Review of The New Ranch Handbook in the Journal of Range Management (Barnes, July 2001).
