Rangeland Ecology & Management

Get reliable science

CONTINUOUS VERSUS ROTATIONAL GRAZING, AGAIN: ANOTHER PERSPECTIVE FROM META-ANALYSIS
Author
Wolf, Kristina M.
Horney, Marc R.
Publisher
Society for Range Management
Publication Year
2015
Body

In an effort to close the continuous- (CG) versus rotational-grazing (RG) debate that has roiled rangeland management discussions for over a century, Briske et al. (2008) reviewed 47 journal articles comparing CG with various RG systems. They used vote counting to tally the number of studies that found significantly greater, equal, or lower production for CG relative to RG for three response variables: animal (AP, both kg/head and kg/ha) and plant production (PP, kg /ha). They concluded that grazing research does not show these two systems produce different results, and that advocates for RG are likely relying more on biased perceptions or anecdotal evidence. Yet vote counting may not be a valid approach for discriminating among influential variables. Our meta-analysis of the same studies revealed some differences between CG and RG not detected by Briske et al.'s review. In general, AP was higher for CG than RG, but PP was not different. However, for every additional year of treatment, AP (kg/ha) under RG increased by 1% relative to CG. Moreover, regression of AP and PP by scale of study (whole ranch vs. research plot) revealed that while AP was higher for CG than RG at the research scale, there was no difference between the two systems at the ranch scale. Additionally, observations that in arid climates AP/head is lower under RG than CG was supported at the research scale, but this was not the case at the ranch scale, suggesting scale plays a significant role in productivity outcomes. Very limited numbers of ranch-scale research studies in the Briske et al. analysis, however, make strong statements regarding grazing system effectiveness difficult. As grazing occurs on over 25% of the world's terrestrial surface, understanding how productivity is impacted by grazing system in real-world conditions is extremely important for economic and ecological sustainability.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM Sacramento, CA