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A Look Back at Thirteen Years of Alfalfa Scissors Cutting Mike
Rankin It is said that you can learn a lot from your past. If this is so, let’s see what we can salvage from our thirteen years of doing alfalfa scissors cutting in the spring. The big picture..... Through the years we have changed the methods by which we take samples, the lab where samples get analyzed for forage quality, locations where the samples are taken, the way we make information available (when we started, the Internet was merely a glimmer in someone’s eye), and incorporated Predictive Equations for Alfalfa Qualty (PEAQ) into our quality estimates and reporting schemes. Through all of these changes, the underlying objective of the alfalfa scissors cut project has remained firm.......to help alfalfa growers predict optimum harvest time based on a desired forage quality. The project can’t accurately predict the actual forage quality of every field in the county, but it can give growers a “big picture” idea of current alfalfa quality and over time offer a good prediction of the RATE of quality decline based on the environmental conditions for a specific year. In effect, the project helps to keep major forage quality “train wrecks” from happening. Some interesting facts and figures.... If alfalfa scissors cutting projects have done nothing else, they certainly have affirmed the fact that planning a first-cut harvest time on calendar date alone will result in wide variations in year to year forage quality. Figure 1 shows the RFV for alfalfa at three different spring dates over the past thirteen years. We can see that: · On May 20, RFV ranged from nearly 280 in 1997 to 144 in 1998. · RFV was lower on May 20, 1998 than it was on June 10 in the years of 1996 and 1997 and nearly the same as the years of 1993, 2002, and 2003. · Using 180 RFV as a trigger, there were only 2 of the 13 years when a producer would not have needed to start cutting before or on June 1st. In 3 of the years, cutting would need to have started before May 20th. · Variation in RFV is greater on May 20th than it is on June 10th.
A look at the averages..... Two aspects of alfalfa forage quality hold the most significance when making a harvest timing decision. These are the actual RFV values on a given date and the rate of forage quality decline over time. The range and average values for the criteria are presented in Table 1.
Soooooo......on average RFV declines about 4 points per day and, on average, we need to be ready to make hay before June 1st. However, the variability from year to year is HUGE! That folks, is why we do scissors cutting projects!
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