When It's a Dry Cut

Drought Hurts Alfalfa Stands More Than Heat

Cheryl Anderson , DTN Staff Reporter
Lack of moisture is more damaging to alfalfa fields than hot temps, according to experts. (DTN file photo by Dan Davidson)

OMAHA (DTN) -- Recent hot weather caused thermometers to spike over 100 degrees in some areas, but a lack of rainfall poses the biggest threat to alfalfa.

Michigan is one of the many states where dry conditions are a bigger worry to alfalfa growers than the heat, according to Phil Kaatz, Extension educator for Michigan State University.

There was only one day in the past month in which soil temperature reached 89 degrees, he said, which was not excessive enough to cause damage.

"When we have plants that cover the soil, alfalfa plants especially, we're not going to have that kind of heat damage at the ground level," Kaatz said.

The severity of drought varies across Michigan. "We have areas that have received 2 to 3 inches in the last month. We have areas that only received a half inch in the last month," Kaatz said. "It all depends on whether or not the storm that went through hit your farm."

Those scattered dry conditions will reduce yields, Kaatz said. Some producers told him they only had half a crop, some told him their alfalfa yields were below average, while others said they had significant reductions in yield.

In southern Michigan, the third cutting is underway, however, in northern areas of the state, the second cutting is just finishing up. Kaatz explained that Michigan is a fairly lengthy state from the Upper Peninsula to the southern border, so the number of cuttings vary due to location, soil structure, the number of heat units, etc. In northern areas, growers usually get two to three cuttings a year, whereas southern Michigan growers can often get up to five cuttings.

Karla Hernandez, extension forages field specialist at South Dakota State University, said she has not seen much damage in South Dakota due to heat, but conditions are very dry, especially in the north.

"We have gotten rain showers on and off, but nothing really significant," Hernandez said.

Hernandez said many producers are wrapping up their third cutting. While the first two cuttings were good quality, some extremely dry areas are struggling to get in a third cutting, and may face reduced yields. Some stands may be very thin, not growing back enough biomass to make haying worth the effort.

This week temperatures are cooler than last week, and there are some predictions for rain, which will be extremely helpful, Hernandez said.

Some North Dakota alfalfa growers are also suffering from the lack of rainfall. Fara Brummer, Extension specialist in livestock systems with North Dakota State University Extension, said alfalfa production in the state is variable. However, some areas have been so dry growers have only gotten one cutting, with yields at only 1.5 tons per acre.

With the exception of those dry pockets, some areas of North Dakota have received adequate rainfall with producers getting two cuttings so far, Brummer said.

Even in Texas, where virtually all alfalfa is irrigated, irrigation was insufficient during the recent hot, windy weather, according to Calvin Trostle, associate professor and Extension agronomist at the Texas AgriLife Research & Extension Center in Lubbock, Texas.

Trostle said only about two-thirds of the historic average of 2 to 3 inches of rain was received in June, increasing irrigation water demand to more than 0.5 inches per day. That water shortage is affecting yields, he said, which are down in some areas, with some stands up to 4 inches shorter than normally expected.

"Alfalfa itself is not hurt by the heat, at least not in the long-term sense, because it is a perennial and established stands have a deep root system; but, of course, short-term yields are indeed less," Trostle said. "No grower here loses a cutting per se, but some cuttings might be delayed, which leads to lower forage quality, and could mean some fields may see one less cut on a season-long basis."

Some growers may achieve one less cutting than normal, Trostle said. As of late July, the next cut in much of the Texas High Plains will be the fourth, which sets up growers for six cuts, or possibly even a seventh provided September and October have good weather.

"Targeted frequency is often driven by the alfalfa forage quality desired, so many producers targeting the dairy market will maintain a cutting schedule even with lower yields," Trostle said.


Many states are experiencing some challenges with infestations of alfalfa weevils and potato leaf hoppers this year.

In South Dakota, Hernandez said, "Our recommendation would be for producers to get out and scout their fields, so they have an idea of how bad their infestations are, so they can decide whether to harvest a little early or apply insecticide."

Alfalfa weevil pressure is also present in North Dakota, Brummer said.

Kaatz said Michigan growers are also being hit by potato leaf hoppers, especially on new seedings. He added that even potato leaf hopper-resistant varieties are seeing damage this year.


Crawford McFetridge (Finger Lakes area of New York State):

Got good cutting at first, but it's been downhill since then. We only had about 1.5 inches of rain since June 5. A nice rain, but a month too late. As for alfalfa here in the Finger Lakes with a D2 drought. It is short, full flowered. Depending upon which field, it is 6 inches to a foot tall. It needs to be clipped, because it is full of hopper burn and in full flower, so there isn't much left after cutting to pick up. Fields that usually loaded 10 trucks, this time might load one truck. This round of hay cutting is bad, but it is simple! No rain, no hay. As for alfalfa it could come back if the rains keep coming.

Dan Hiller (northwest Ohio):

Rains here have been spotty. Even where it rained it was not enough and the alfalfa is short. I think it is a combination of both around here. Saw a field in Crawford County on Sunday in full bloom that was a foot tall -- they had more rain than here. My gauge has had only .79 inch for the month of July. Corn is holding in color, but you can see damage now.

Jeff Littrell (southeast Minnesota):

We came into the heat with 1.5 inches of rain and the day after we got 2.17 inches of rain. Our son has all new seeding with standing oats. His new seeding is the best I've seen. Our son will only have one cutting, but it could be as much as 3 ton per acre on first cutting new seeding. If we can get another 2 inches during fill our son's organic corn will be the best I've seen and my personal best was 145 bushels per acre and it looks like it will be above that. Time and weather will tell.

Keith Landis (northern Illinois):

Alfalfa conditions have been good in our area and yield has been good so far. Moisture has not affected our stands, but rains have made it difficult to make dry hay over the past several weeks. For dairy quality hay, we are coming up on the fourth cutting. For horse hay, we are working on the second cutting. We will have more cuttings of the dairy quality hay due to reducing the interval between cuttings to make higher quality hay.

Clayton Kline (northern Missouri):

Dry conditions are a problem here. Whether the lack of moisture or the heat is actually causing harm to the alfalfa in this area, I cannot say. But the lack of rain is for sure cutting production. Unfortunately for one grower I know, he mowed down what appeared to have been a reasonably good second cutting, only to have an inch or so of rain fall on it the next day. Usually in this area too much rain causes more stand damage than not enough.

Cheryl Anderson can be reached at Cheryl.anderson@dtn.com


Cheryl Anderson