Pasture yield mapping: why & how

Abstract

Spatial variation in pasture yield within a single paddock can be high. Measuring this variation has many potential benefits. For instance, cost-effective targeted treatments could be applied to low yielding areas resulting in increased pasture yield at a paddock scale with minimal cost. Understanding pasture yield variation requires tools that can measure it, and practical methodologies to guide how and when to use these tools to obtain useful data. The study reported here aimed to develop measurement protocols for using the C-Dax pasture meter to map yields of rotationally grazed pastures. The general principles should be applicable to other measurement tools. The pattern of pasture yield varies throughout the year. Because growing conditions change with the seasons, areas of a paddock that perform well in summer may perform poorly in winter, and vice-versa. Time of year is therefore an important consideration for measurement purposes. The recommended protocol developed from this project to estimate the spatial variation in annual yield on a paddock is to: • map 1 month following peak pasture growth rates; • drive at up to 50 m run spacings, but close enough to cover all features of interest; and • map as close to the grazing event as possible within the final third of the regrowth period. Keywords: Yield mapping, pasture, precision agriculture, pasture height, dairy, spatial management