Walk the field or paddock to be measured and take a minimum of thirty readings (plonks) as you walk across a representative part of the area. This will take into account the better and worst areas giving you a much more accurate cover assessment. It is advisable to take the same route across the field week after week so that you have comparable data. If there is more than one person walking the farm then it is advisable to put markers on posts and this makes it easier to follow the same route each time. Do not choose where to place the plate meter as it must be random so that you get a good representation of covers in the field. Also it is important to place the plate meter rather than use a walking stick motion or push down.
The reason you need to take a minimum of thirty plonks is to even out the extremes of growth you may encounter. The key is to take as many as possible.
Plate meters are designed for grass clover swards and they are most accurate between 1800 and 3000kg DM/ha.
If the pasture meter is not reading correctly
If the plate meter is not reading as you expect then check:
· There is no grass wound around the bottom of the plate.
· That you are placing the plate meter vertically in the pasture and not rocking it like you would with a walking stick.
· The density of the pasture at the base; if the sward is really thick and dense at the base of the sward the reading may be correct as the density has a large affect on the plate meter reading.
Accuracy and technique is very important when measuring and not using the plate meter correctly can lead to pasture covers varying up to 600kg DM/ha which can lead you to believing you have adequate covers or surplus when the reverse maybe true.
Using the correct technique there is no difference in readings between the electronic and mechanical plate meters.