We have begun monitoring of 1st cutting for quality this year.

If you are not familiar with our procedures we use alfalfa height to predict Neutral Detergent Fiber (NDF) for alfalfa, alfalfa/grass mixed and grass stands. Alfalfa height has proven to be a reliable indicator of NDF values in the field. Here are numbers that are helpful when using alfalfa height as an indicator of NDF content:

In general we say 100% grass stands should be cut when nearby alfalfa is 14 inches tall to achieve the desired 50% NDF.

Begin cutting 50/50 mixed alfalfa and grass stands when nearby alfalfa is 22 inches tall for the desired 44% NDF.

Begin cutting 100% alfalfa stands when alfalfa is 28 inches tall for the desired 40% NDF.

The desired NDF for all grass fields is 50%, 50/50 mixed alfalfa and grass fields is 44%, and pure alfalfa stands is 40%. Predicted days to cut are based on daily NDF increases for grasses of 1% point, 50/50 mixed stands of .8% points and alfalfa of .5% point. Typically NDF increases about 0.8 to 1.2/day for grasses expecting the lower end of that range in cooler weather and the higher end in warm. Alfalfa NDF increases about 0.4 to 0.7/day again figuring the lower end of that range with cool temperatures and the higher in warm. Predictions are adjusted for the coming week’s weather and right now we are assuming normal growth.

In the attached tables locations around the region are listed where we have measured alfalfa height. You can use the location and elevation as a guide to conditions that may be similar to your own.

Every year is certainly different and 2015 is no exception. We did a dry run last week feeling that the fields were behind enough not to justify reporting. It appears we may just gone through one of the biggest jumps in alfalfa growth since we have started this monitoring. Since last week we had some alfalfa fields grow 9-11 inches where typically large jumps in the past have been in the 7-8 inch range. The warm temperatures really pushed alfalfa growth. However grass growth was atypical due to the dry conditions and is short by 2-4 inches as we now see some heading out. This is a reminder that grass may be behind in growth (yield) but it isn’t behind in maturity or fiber accumulation. So check your all grass or mostly grass fields there is a good chance they may need cut. Even mixed stands should be given some scrutiny!

As always use information in the attached table as a guide to know when to harvest by checking your fields! Next report May 19!



May 12, 2015 Quality Summary (pdf; 372KB)