[Table of Contents] Rising Plate Meter Dry Matter Estimates How to use this chart: Determine the grass height in each paddock with a Rising Plate Meter Find your grass height on the X axis (across the bottom). Move up to the line that best describes your grass. Read the kg/ha on the Y axis (left side of the chart). lb/acre = kg/ha * .89

Arriving at exact lb/acre or kg/ha is impossible and unnecessary. What we really need is a good estimate to plan the maintence of the grazing wedge and to help us decide whether to graze the cows in a paddock today, next week, split it up, or to save the paddock for silage. If we are, let's say, 20% off in our estimates, it isn't of major importance. So long as we are consistent in our measurements and calculations, we will probably always be off in about the same way and can learn to compensate. Of course, it will be much easier to compensate if the estimate is over rather then under! The five New Zealand Formulas for estimating dry matter: I don't know for certain that I have these quoted correctly, nor do I know how widely accepted they are in New Zealand. Season Formula 1 Winter and early Spring (before stem growth) height in centimeters x 125 + 640 = kg/ha 2 Late Spring and early Summer (during stem growth) cm x 130 + 990 = kg/ha 3 Mid Summer cm x 165 + 1480 = kg/ha 4 Early Autumn (before autumn rains) cm x 159 + 1180 = kg/ha 5 Late Autumn (after rain) cm x 157 + 970 = kg/ha The US Semi-Standard Fromula for estimating dry matter: This formula is not accepted by everyone but is the best guide currently available. Season Formula All seasons 1 inch = 432 lb/acre Why does it matter? First some background: There are two kinds of dairy farmers doing Intensive Grazing in the United States: (1) Those making real progress (2) and those that are just "spinning their wheels". The simplest way to draw the line between these two groups is with the Grazing Wedge Concept. If a dairy farmer establishs and maintains a grazing wedge, then most likely that fellow is making progress. If he grazes but ignores the grazing wedge concept or doesn't even know what it is, then that fellow is probably just "running in place". It is essential to estimate the amount of grass in the paddock in order to establish and maintain a grazing wedge. One way to estimate the amount of grass is with a Rising Plate Meter. But a Rising Plate Meter measures inches of height (as depressed by the weight of the plate). The height in inches must be converted to pounds of dry matter per acre or lb/acre or kg/ha. A grass researcher would clip a bunch of representative samples, dry them, and weigh them. Most farmers aren't able to do that, but they can use a formula to convert the inches to estimated lbs/acre. An example formula is: 1 inch of height (depressed) = 432 lbs / acre [Table of Contents] [Top] [fwo@ bright.net]