Continued rain this year is a blessing to keep pastures and fields growing and green. However, short drying windows may make alfalfa harvest tricky.
The timing and amount of rain is important. Legumes like alfalfa are more impacted by leaf shatter from raking or turning than grasses. A bit of moisture on new hay before drying has minimal impact, but heavy rain (>1 inch) can cause up to 10% of soluble nutrients to leach out. Multiple rain events in a row can result in nutrient losses up to 30%.
To keep impact low, we need to speed up the dry-down process. Spreading windrows as wide as possible, conditioning at harvest, and proper raking can reduce dry down from 2 days to ½ day under good conditions. Alternatively, consider higher moisture uses like haylage or balage. While soil moisture and compaction still need consideration, you can clear a field in 2 days or less when the forage doesn’t have to physically be dry.
Finally, preservatives can be used to bale at slightly higher moisture levels without the mold and heat issues typically experienced. We can’t bale at moisture levels used for ensiling, but it does allow us to get into the field a bit sooner.
If we do need to wait for harvest, hay quality will decrease as the plant matures. Work done at the University of Wisconsin showed for every day harvest was delayed, 100 lbs. of yield per acre was gained while 5 to 4 points of RFQ were lost. The actual physical growth also makes an impact as taller plants are more susceptible to lodging if moisture continues. Be aware that plants may start growing new shoots from the crown as they mature. If we harvest two low, these new shoots will be cut off along with the mature plant. This set back can delay the next cutting by up to a week.
Fortunately, you can avoid this delay. Scout before harvest and if new growth is present, raise your cutting height just a couple inches so you avoid clipping off most of these new shoots. Your regrowth will have a head start towards the next cutting and since the stubble you leave behind has quite low feed value anyway, the yield you temporarily sacrifice is mostly just filler.
The last thing I want to talk about is windrow disease, the name given to the striped appearance in fields where alfalfa windrows remained so long that regrowth was delayed
Windrow disease presents special challenges. Weeds often invade, requiring spraying to maintain quality and protect stands. During the next growth period, plants that were not smothered regrow rapidly, while plants underneath the windrow suffer delays. Part of the field often will begin to bloom while windrow-stressed plants are still short and tender. So when do you harvest? When the first plants begin to bloom or do you wait until injured plants are ready?
I suggest using two factors to tell you when you should cut — the health and vigor of your stand and the nutrient needs of your livestock. For example, is your alfalfa stand young, healthy and regrowing well? If not, wait to cut until stunted plants begin to bloom so you can avoid weakening them even more.
But, if your alfalfa is in good shape, then cut when it will best meet the needs of your animals. Dairy cows need alfalfa that is cut early, so harvest when the first plants reach bud to early bloom stage. Regrowth of injured plants may be slow after cutting, but this sacrifice is needed for profitable milk production. Beef cows, though, do not need such rich hay. So if the hay will be fed to beef cattle, let stunted plants recover, and then cut when they are ready to bloom.
-Ben Beckman is a beef systems Extension Educator serving the counties of Antelope, Cedar, Knox, Madison and Pierce. He is based out of the Cedar County Extension office in Hartington. You can reach him by phone: (402) 254-6821 or email: ben.beckman@unl.edu