Estimating Grazingland Yield from Commonly Available Data

Abstract

Range managers must often estimate or predict annual forage yield at a distance, from minimal data, or for a variety of sites. Six simple formulas potentially useful for this purpose were compared and modified. The grazing data that were used represented 44 sites on 5 continents. Soil texture at site affected accuracy of all formulas. Shrubbiness affected accuracy of formulas based on evapotranspiration. Some formulas modified to include past-year yield as a variable were fairly accurate over a variety of grazing-lands. An equation based only on past-year yield predicted yield within an average of 34% at new sites. Equations that incorporated past-year yield, used a measure of current effective moisture and had a limiting-factor approach estimated current yield within an average of 18-19% at new sites.