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Thursday, May 21, 2015

Alfalfa Harvest Alert Info - May 21, 2015


By Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties, marte011@umn.edu, 320-968-5077 if a local call to Foley or 1-800-964-4929

Here is a link to all the Alfalfa Harvest Alert Scissors-Cut information we have received so far from sampling done on Thursday May 21: May 21 Alfalfa Harvest Alert Scissors Cut Data

Please let me know if something looks to be in error.

Please note cooperators and sponsors listed in this report, and tell them and cooperating farmers, “Thanks for your efforts with this.”

Please plan and works for a SAFE hay harvest.

Hope you have a meaningful and enjoyable Memorial Day.

On behalf of U of M Extension Colleagues Nathan Winter and Abby Neu, 
and the Central MN Forage Council

Assessing frost injury to soybean: Is there an interaction with soil-applied PPO herbicides?

Jeff Gunsolus, Extension Weed Scientist

As people begin to assess soybean stands following the low temperature conditions of May 19th, questions are coming my way regarding the possible interaction of frost with soil-applied PPO herbicides. Is it possible? My answer is yes. Is it widely prevalent? As I receive more reports from around the state my current answer is, not likely.

An interaction of frost with soil-applied PPO herbicides is possible because cold temperatures slow the rate of emergence of the soybean through the herbicide-treated soil and the soybean is limited in its ability to metabolize the herbicide. However, the crook stage of the soybean plant that is expressing injury symptoms appears to be targeted to soybeans planted in early May (May 2 to 4 are frequently mentioned). Soybeans planted in early May were just cracking from the soil at the time of the low temperature conditions and were vulnerable to freeze damage.

Wednesday, May 20, 2015

May 7 Hay Auction.... AND Alfalfa Harvest Alert Info thru May 20

By Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties, marte011@umn.edu, 320-968-5077 if a local call to Foley or 1-800-964-4929

I am posting information and links to documents with data from

1. May 7 2015 Sauk Centre Hay Auction

2. May 18-19 Alfalfa Harvest Alert Scissors Cut Data

Tuesday, May 19, 2015

Frost injury to soybean

Bruce Potter, IPM Specialist, Phyllis Bongard, Extension Educational Content Development and Communications Specialist, and Seth Naeve, Extension Soybean Agronomist


Figure 1. Projected low temperatures ending Tuesday, May 19.

Spring frost damage to soybean is relatively rare in Minnesota, as the last average frost dates usually occur before soybeans are normally planted. However, soybean planting and emergence is well ahead of the 5-year average, leaving the crop more vulnerable to early season frost events. Temperatures dropped into the low 30s and upper 20s (F) overnight in the west-central and northwestern parts of the state, likely resulting in some degree of frost injury to emerged soybeans in select areas.

Monday, May 18, 2015

Frost injury to corn: What to expect

Jeff Coulter, Extension Corn Agronomist

This year’s early and dry spring has facilitated some of the earliest corn planting dates of all time in Minnesota. This early start to the growing season should allow the corn crop to pollinate earlier than normal. Early corn planting also allow kernels to fill when days are longer, reduces the risk of injury due to an autumn freeze before crop maturity, and allows increased time for grain dry-down prior to harvest.


Assessing frost injury


Patchy frost is expected across Minnesota tonight and tomorrow morning. Frost damage can occur when air temperatures are in the mid-30s on calm nights, as the lack of wind allows the transfer of heat from air near the ground to the air above, resulting in colder temperatures near the soil surface. In general, frost damage tends to be worse in low areas where cold dense air settles, near field edges where vegetation reduces the potential for heat transfer from the soil to the air above, and in fields where high levels of surface residue coverage limit heat transfer from soil. In addition, fields that were recently row-cultivated prior to cold temperatures are more susceptible to frost injury, as tillage dries the surface soil, thereby reducing the amount of heat and moisture that can be transferred between the soil and air.

Monday, May 4, 2015

Will soil-applied herbicides work in a dry year?

Tom Peters, Extension Sugarbeet Agronomist

Two questions are on farmers minds. First, how long will soil-applied herbicides ‘last’ in the soil if it doesn't rain and second, should a farmer consider using a rotary hoe or drag harrow to incorporate herbicides?

Volatility (evaporation), adsorption, and soil moisture effect soil-applied herbicides. Volatility is the change in herbicide physical state, from a liquid to a gas. Most soil-applied herbicides used by farmers have a medium or low vapor pressure meaning they generally will not volatilize during warm and dry conditions. However, understand that herbicides sprayed on soils will move with blowing soil and these effects may impact efficacy. Adsorption is the attachment of herbicides to soils. Herbicides must be bound to soils or they would easily leach away. Most herbicides are moderately or strongly bound to soils colloids and should not be impacted by our dry conditions.

Soil moisture (and rainfall) affects soil-applied herbicides in two ways. First, rainfall moves the herbicide from the soil surface and into soil. Second, rainfall contributes to the amount of herbicide available for absorption by weeds. While ‘half an inch’ is a good rule of thumb to activate herbicides, soil moisture conditions at or after the time of soil-applied herbicide application will influence herbicide activation. Rainfall must first wet the soil surface before water and the herbicide can move into the soil profile under dry conditions. Additionally, herbicides bind more tightly to soils and are less active for weed control in dry conditions. Thus, under our dry conditions, it might take more than 0.5 inch of .rainfall for satisfactory levels of activation and resultant weed control. But on the other hand, your herbicide should be ‘there’ and available for activation once we get rain...provided the soil does not blow.

Our soils are extremely mellow and powdery this year due to the dry conditions during tillage. Running a tractor and pulling an implement across fields may disturb too much soil and may break the ‘herbicide barrier’ and thus do more harm than good.

We recommend farmers continue to use soil-applied herbicides for grasses and small seeded broadleaf weed control in row crops in freshly planted row crops, even though it has been dry. Remember, farmers are using soil-applied herbicides primarily for control of waterhemp and other small seeded broadleaves such as common ragweed, lambsquarters or redroot pigweed. These weeds germinate at our near the soil surface and are in dry soils. Waterhemp will generally not germinate and emerge until mid to late May, depending on where you farm.  And....we will eventually get rain to activate these products.

There might be weed escapes from deep germinating weeds like giant ragweed or wild oat that germinate and emerge from moisture and will need to be controlled with postemergence herbicides.

Thursday, April 30, 2015

Announcing the University of Minnesota's Institute for Ag Professional 2015 Summer Educational Programming

Dave Nicolai, Extension educator - crops

2015 Ag Professional Field School

July 29 & 30, 2015 – St. Paul, MN

UofM field school

A hands–on, in–field program emphasizing crop and pest management diagnostic skill building in field crops. The program is geared to the educational needs of new and recently employed ag professionals who are in a beginning to intermediate phase in their agronomy careers.
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