New Tool Will Help Estimate Alfalfa Yields from Plant Height

  • Nov 10, 2015
Many farmers have good yield estimates of grain crops, but not for forage. This lack of forage yield knowledge results in failure to adequately inventory forage supply for animals and an inability to estimate performance of stands or management practices.
WinField, along with the University of Wisconsin’s Dr. Dan Undersander, recently conducted a study to determine the relationship between alfalfa plant height and yield among fields with good stem density. Samples were taken at varying heights and stages of plant development from 58 production alfalfa fields in Iowa, Minnesota, Wisconsin, Nebraska, South Dakota, Michigan and Pennsylvania.
Previous attempts to estimate yield from plant height over a range of stem densities have largely been unsuccessful, likely due to the effect of stand density on limiting yield. But, when taking measurements in a field with non-yield-limiting stem density (more than 55 stems per square foot), the correlation of height with yield was 0.66, with yield increasing an average of 126 pounds of dry matter per acre per inch of height.
Use of plant height to estimate alfalfa yield could help farmers determine the yield range of fields and whether changes in management would increase yield. Good management (dense stands, good soil fertility, and insect and disease control) is key to getting high yields. Data indicate that, with current prices of $200 per ton for high-quality hay, alfalfa is worth about $16.60 per inch of height per acre.
These findings led WinField to develop a tool called the Predictive Alfalfa Yield (PAY) Stick, designed to instantly measure the response of high-management treatments on alfalfa acres by estimating yield per acre. This provides farmers with an easy assessment if the application had an effect on yield as compared to a non-treated field. The PAY Stick can also help growers determine which fields are the highest producing or to compare yield between varieties.
Stay tuned for more information on the WinField PAY Stick, and ask your local WinField representative how it can help you meet, and even exceed, your alfalfa yield potential goals.