OBJECTIVE:
To determine the optimal division of a pasture in a Management Intensive
Rotational Grazing (MIRG) system.
DESCRIPTION:
BACKGROUND: Management Intensive Rotational Grazing (MIRG) is a grazing
strategy designed to maximum the productivity and economic benefit of a pasture
by capitalizing on ecological factors that control productivity. In practice, a
pasture is divided into parcels that are grazed for a limited time and
subsequently allowed to recover before being grazed again. This strategy
increases the productive capacity because most of the pasture is left in fallow
so the grasses can recover. Other advantages that improve productive capacity
include managed nutrient cycling, diverse seasonal productivity of grasses, and
improved management of genetically favorable grasses. Traditionally, pasture
division has been conducted with little rationality behind it other than
availability of drinking water for animals and "common sense". The decision to
use GIS is based on the assumption that a rational approach to dividing pasture
land will result in cost and labor efficiency and maximum productivity.
SETTING: Three parcels that make up an 1800-acre ranch in a semi-arid region of
eastern Washington State have been selected as the site for this project. The
site varies dramatically in topography, vegetation, soil quality, and water
availability making it an ideal setting for this experiment.
TASKS TO BE PERFORMED: Use soil, vegetation, and surface water data to quantify
and map the expected availability of forage for the pasture. Define criteria
for different "management intensity" scenarios. Locate topographically
appropriate places to build fences. Partition pasture according to different
"management intensity" scenarios and determine carrying capacity and rotation
schedules for each scenario.