Find the Yields

Find the Yields

The next step to build a rotational grazing plan is to find the yields of your pastures. This tells you how much forage is available for your flock.

Thank You USDA

The amount of forage grows depends on many variables, including how much rain falls, what the temperature is, and what kind of soil is in your pastures. It all seems overwhelmingly unknowable—until, to the rescue, comes the United States Department of Agriculture!

Here’s how to find the yields.

Determine Your Soil Type(s)

  1. If you don’t already know it, you can determine the soil type(s) in your grazing area(s) with this handy USDA online tool.
  2. Find the NRCS Soil Survey for your state.
  3. Then look in your state soil survey to find the soil survey for your county.
  4. In your county soil survey, look in the table of contents to locate the pages that relate to the soil type(s) in your pastures. Make notes!
  5. In your county soil survey, there will be a section with general descriptions of soil types, and also—amazing!!!—a section labeled something like “Use and Management of the Soils” with a subtopic something like “Use of the Soils for Range.” Based on the government’s extensive records of what happened in past, this is where you can find out how much forage your pasture will grow for your flock. Amazing!!!

Now Find Your Total Forage

  1. For each paddock, multiply the number of acres in paddock by the expected forage production per acre of the soil in the paddock. This gives the total forage expected to be produced in each paddock.
  2. You can utilize these forage numbers in Page 2 of our Rotational Grazing Planning Tool, “Field Days.”

Variable Rainfall

  1. In Sonoma County, the USDA Forest Service and Soil Conservation Service published a soil survey in May 1972 in partnership with the University of CA. This is the soil survey we are using for calculating forage production.
  2. Our county soil survey lists two different forage production values for each soil type. One is for a “favorable moisture year” (plenty of rain) and another is for an “unfavorable moisture year.”
    • 20 inches/year was the mark for a “low rain” year. 35 inches/year was the mark for a “high rain” year. Of course, these are just assumptions, or starting points.
    • We stay aware of how much rain actually falls here. We get our data from a weather station near our grazing site. This lets us know whether we are in a “low” or a “high” rainfall year.
    • The rainy season starts around November and goes until around March, maximum.
    • Rainfall can vary widely year to year.
    • For example, in all of 2020, our area received only 9.71 inches of rain.
    • Knowing this tells us that our forage yield figures likely are going to be lower in 2021 than what the 1972 soil survey reports for an “unfavorable moisture” year.
    • So we start with the “low rain year” number from our county soil survey for this year’s expected pasture forage yields.