About the Disc Pasture Meter The disc pasture meter (or DPM) is an aluminium instrument used to determine grass biomass per hectare (kg dry grass/ha). It is an easy alternative to cutting, drying, and weighing grass samples for measuring biomass. The grass biomass data is then typically used for the following.
- Determining the grazing capacity on a property or a single camp/paddock
- To make decisions regarding prescribe burning
How does it work? The DPM consists of a disc attached to a tube which slides over a rod fitted with measurements in centimetre (see illustration). The disc and tube unit are dropped onto the grass sward with the rod placed vertically to the ground. The height (in centimetres) at which the disc settles is then recorded where the rod meets with the upper fringe of the tube. At least fifty such recordings are made at one sample site after which the average (in cm) is calculated. Recordings are usually done on a straight transect at one step intervals.
How is biomass determined? Grass biomass, or standing crop, in kilogram dry grass per hectare (kg/ha), is then calculated by using an equation. Various equations are developed by pasture scientists through calibrating the DPM for certain grassland and savanna regions. These equations are supplied with the instrument or can be downloaded from our resources page.