Paddock Size and Stocking Density Affect Spatial Heterogeneity of Grazing
Issue Date
2008-07-01Keywords
deferred rotation grazinggrazing management systems
intensive rotational grazing
livestock distribution
short-duration grazing
time control grazing
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Show full item recordCitation
Barnes, M. K., Norton, B. E., Maeno, M., & Malechek, J. C. (2008). Paddock size and stocking density affect spatial heterogeneity of grazing. Rangeland Ecology & Management, 61(4), 380-388.Publisher
Society for Range ManagementJournal
Rangeland Ecology & ManagementDOI
10.2111/06-155.1Additional Links
https://rangelands.org/Abstract
The claim that intensive rotational grazing (IRG) can sustain higher stocking rates can be partially explained by more even spatial distribution of grazing such that livestock consume forage from a greater proportion of a pasture. To test the hypothesis that utilization is more even at the higher stocking densities of smaller paddocks, mean absolute deviation (heterogeneity) of utilization estimates by plot was compared in paddocks of sizes and stocking densities representing increasing subdivision from two-paddock deferred rotation grazing (DRG) to 16-, 32-, and 64-paddock, two-cycle IRG. These 70-, 4-, 2-, and 1-ha paddocks were grazed for 7 wk, 4 d, 2 d, and 1 d, respectively, at 32 animal unit days (AUD) ha-1 during 2000 and 34 AUD ha-1 during 2001. Within IRG there was no response to the treatment gradient. After one cycle in the IRG paddocks, heterogeneity of use was generally lower than in the DRG paddocks, in both 2000 (3-11% [outlier 18%] vs. 14-19%) and 2001 (9-17% vs. 24-28%). After a second cycle in 2001, heterogeneity in half of the IRG paddocks (17-21%) was nearly as high as the early-grazed (24%), but not the late-grazed (28%), of the DRG paddocks. This lack of a stronger difference between systems was probably due to the fixed two-cycle IRG schedule and lack of plant growth during the nongrazing interval. Across both systems heterogeneity of utilization was strongly positively correlated with paddock size. Because utilization was not severely patchy in the largest treatment, the difference between systems would likely be greater in commercial-scale paddocks. Thus grazing distribution can be more even under intensive than extensive management, but this depends on how adaptively the system, particularly the aspects of timing and frequency, is managed.Type
textArticle
Language
enISSN
0022-409Xae974a485f413a2113503eed53cd6c53
10.2111/06-155.1
Scopus Count
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