[Table of Contents] The Grazing Wedge Page The concept of "THE GRAZING WEDGE" continues to elude most folks interested in grazing, including the majority of all those in the USA who are directly advising dairy graziers. Actually, many experts talking at grazing seminars don't have a clue about the importance of the "Grazing Wedge" or even what it is. That is why they end up spouting nonsense about what to plant and how to build fence while totally ignoring Voisin Grazing Management principles. The establishment and maintence of a "Grazing Wedge" is essential to measuring success and to further progress. Hopefully, working through the following graphics will convince folks to pay attention to their "Grazing Wedge". The graphs below are intended for use with Bluegrass/White clover or Perennial ryegrass/White clover pastures. This type of low growing, dense pasture will have about 432 pounds of DM per inch when measured with a homemade rising plate meter. Those folks trying to graze hay type plants will need to use a different formula for a year or two until their pastures evolve to Bluegrass/White clover or Perennial ryegrass/White clover pastures -FWO Please see: Graze-L Archives Referring to the "Grazing Wedge" An Acrylic Plastic Weight Plate for Estimating Forage Yield Pasture Plate Construction Details Monitoring Pasture Supply Using Average Herbage Cover Measuring Pasture Productivity

The vertical black lines in the graph above correspond roughly to inches of height while under compression by the plate of a rising plate meter. The line labeled 432 is about one inch, 1296 is about three inches, etc. Growth at low pasture masses is pretty slow because the plants have limited leaf area and can't catch much light. If few or no leaves are present, the root reserves will be depleted just to push up a few leaves to get the process started. As the leaf area slowly increases, the growth rate also gradually increases eventually becoming rapid at around 1100 lbs of dry matter per acre of pasture mass. It's best to eternally maintain pasture mass of at least 1100 lbs dry matter per acre or the total production for the year is drastically reduced. Once pasture masses increase above around 2700 lbs dry matter per acre the growth rate drops off, eventually falling to almost nothing. The lower leaves and low growing plants get shaded out as the pasture grows taller. Not only do these shaded lower plants fail to photosynthesize but until they die, actually steal from the parts of the plant that is intercepting sunlight. A double whammy! That's why pasture production is greatly reduced if the swards get more than 6 or 8 inches tall. -FWO In the graph below, each vertical bar represents the amount of grass in a single paddock on a farm with 30 padddocks.

Evaluating your own "GRAZING WEDGE" This is something that has to be done at least once a week..FOREVER! The first step is getting the data. All you need is a simple rising plate meter and a paper and pencil. My rising plate meter is an old piece of window plexiglass that was salvaged when my son threw a baseball through the window between the milking parlor and the milkhouse. We stuck a tread-in fence post through a hole in the plexiglass. The fence post has a few notches carved in it that indicate pounds of dry matter per acre from 1000 to 3000. If you are compulsive enough, you could write down a dozen or twenty measurements in each paddock and average them to get a reading per paddock. I just walk around in the paddock taking readings until I come to some kind of a decision. I just write down one number per paddock. That number is my best guess at current dry matter per acre. 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! Here is a sample worksheet for recording data from 30 paddocks: After assembling the data, the next step is to sort the paddocks by dry matter per acre. And to divide the paddocks into these groups: Paddocks too mature to graze with the milking herd. The paddocks that will be used over the next seven days. Paddocks too immature to graze in the coming week. The best tool for the job is a simple computer spreadsheet. Below are the sorted and categorized spreadsheet results as well as a graph showing the current "Grazing Wedge"

What did we learn? We know which paddocks are too mature for the milking herd. We know which paddocks to graze tomorrow and for the rest of the week. We know the shape of the "Grazing Wedge". Which in this case is showing no serious problems but looks a bit too mature as a whole. If it rains soon, we will have way too much coarse grass. More to be added later! -FWO [Table of Contents] [Top] [fwo@ bright.net]