Tuesday, May 24, 2016

Recovering from Cold Temperatures and Frost

Abnormally cold temperatures and frost created significant injury in most corn and some soybeans.  Many soybeans were planted late enough that they had yet to emerge by the time of the cold temperatures and frost on 5/14/16 and 5/15/16.  By and large soybeans were spared from the frost, that said, several thousand acres of early planted soybeans will be replanted in Southeastern Minnesota.

Corn injury and recovery appears to be influenced by planting date.  Reports from the earliest planted corn (4-10-16 to 4-12-16) are that injury was not too significant and that they have recovered well.  I have not validated these claims with any of my own observations.

The second corn planting date, around April 19th, sustained serious damage and has had the most difficult recovery.  My infield observations are that stands have not been reduced by much, if at all, by the frost. That said, the crop has come back unevenly and upwards of 20,000 of plants per acre remain buggy-whipped or tied up as of Monday May 23rd (stand counts remain at 34,000 to 35,000).  Plants from this planting date exhibit a wide range of symptoms that vary by field and within fields.

Damaged

Damaged Recovering Normally

Damaged Recovering Buggy-whipped

Damaged Recovering Buggy-whipped

Damaged Recovering Buggy-whipped

Damaged Recovered Leaning

Dead

Corn planted in the 3rd planting date around the 26th of April appeared to have sustained the most significant damage initially, but they are recovering better than the second planting date.  Generally this corn looks better and has fewer buggy-whipped plants.  Generally there are 3,000-8,000 plants per acre that are buggy-whipped.  Attempts to "unfurl or untie" plants by clipping have very mixed results and have the potential to cause negative results.  A good overview on this topic can be found here: http://cropwatch.unl.edu/2016/risk-freeze-damage-early-planted-corn

Finally, corn planted the first part of may was not affected by the frost.  It is one or two stages behind early planted corn, but looks nice and healthy.

  

 We will update as the season continues.  We would appreciate learning about what you are experiencing, so don't hesitate to contact us or post a comment below.

Ryan Miller
mill0869@umn.edu

Friday, May 13, 2016

Watch for Giant Ragweed Emerging in Early Planted Soybeans

May 13, 2016

Southeastern Minnesota has been busy planting corn and soybeans over the past 4 weeks.  Much of the corn was in before the end of April and several fields of soybeans were planted before the calendar was changed to May as well.  Once May came, there were many good planting days, so much of the soybean crop is now in the ground, too.  It is great to have the crop in the field, isn't it.  For a number of folks, there were also windows of opportunity to apply preemergence herbicides on both crops.

Applied or not, the next job on the list is to watch the emergence of your crop and weeds.  An early planting favors giant ragweed, one of our first troublesome weeds out of the ground.  We already have seedling giant ragweed in our corn herbicide trials (planted April 25).  The plots with no preemergence herbicides or ones with herbicides weak on giant ragweed have a nice carpet of seedlings in them.  The message, this weed grows quickly and can pass the 2-3 inch mark very quickly.  Once past the 2-3 inch mark, it becomes more challenging to control, especially if it is herbicide resistant. There are several good options for post emergence control in corn, but not so in soybeans.

If you are dealing with glyphosate resistant giant ragweed in RR soybean, you need to target them at 2 inches with a SOA-2 or SOA-14 herbicide.  Examples include FirstRate, Flexstar GT, or Cobra.  If you also have SOA-2 resistant giant ragweed, the FirstRate will not work for you.  If you planted LibertyLink soybean and did not get a preemergence herbicide on, you need to target the first glufosinate (Liberty) application when the ragweed is small and include a residual that will help with the giant ragweed and other weeds.  See results from our 2015 herbicide trial near Rochester on SOA-2 and SOA-9 resistant giant ragweed for more details. 
Weed Control Programs for SOA-2 & SOA-9 Resistant Giant Ragweed

To view more herbicide trial results in corn and soybeans check out our complete report at:
2015 Southern Minnesota Crops Research Report

Seedling giant ragweed

Lisa Behnken, Extension Educator, Crops (lbehnken@umn.edu)  

Tuesday, May 3, 2016

Manure and nitrates in United States courts



Most people are aware of the lawsuit currently going on between the Des Moines Water Works utility and three county drainage districts upstream of its water supply over nitrates in in Des Moines drinking water.  A lesser known case, but equally important for agriculture, is the one decided against Cow Palace LLC, a dairy farm, by the Eastern District Court of Washington State.  There is a well-written article by several Minnesota lawyers and economists here that discusses the implications of these two cases.  Take a look.

My understanding of the law is about on par with my understanding of astrophysics, so a lot of the “legalese” is above my head.  But a few lines really stood out to me that relate to the Cow Palace/Dairy Farm case, manure application, and environmental risk.

“The RCRA agricultural-waste exemption was limited by the court, which held that manure is to be regulated as a solid waste similar to garbage if it is ‘handled and used in a manner that its usefulness as a fertilizer is eliminated’…In the Dairy Farm case, the court essentially shifted the burden to the farm or livestock operation to show that manure is only being applied to land as a beneficial fertilizer to be used by crops in the root zone.”

A little background on the Cow Palace/Dairy Farm case: a dairy farm operator in Washington State was sued by two community groups that claimed the farm was violating the Resource Conservation and Recovery Act (RCRA), which prohibits the disposal of solid waste to the land.  Manure is generally considered exempt from this law because it’s used as a fertilizer source on the land.  However, what the court did by ruling in favor of the community groups was suggest there are limits to that exemption, and that those limits relate to whether the manure application was intended to fertilize crops or to dispose of manure.

Here are my thoughts on what this court case means for farmers:     

1. It’s putting the burden on farmers to show they’re applying nutrients in manure at agronomic rates- no more than what the crop will be taking up.  Cow Palace/Dairy Farm got in trouble because they were applying manure to empty out the lagoon, not to apply to cropland at agronomic rates.

2. It’s really important to keep records of manure applications and manure analysis results so you can demonstrate you were applying at agronomic rates.

3. It points out the legal importance of following good manure management practices.  Practices have to be defensible, and the best way to do this is by following University research-based guidelines and replicated on-farm research.  University of Minnesota publications and fact sheets regarding manure application can be found here.