Allamakee SWCD hosted Cover Crop Field Day with area producers

The Allamakee County Soil and Water Conservation District hosted a cover crop field day on Thursday, April 6.  Area producers had the opportunity to stop by three different sites and drive by two additional sites to view cover crops.  All of the fields also had manure applied before or after seeding the cover crop.  The field day offered producers the opportunity to view different methods of cover crop establishment and manure application and see that the two practices can work together.  This field day was funded through a grant from the Leopold Center for Sustainable Agriculture.   Speakers included project coordinator, Sara Berges; NRCS Area Agronomist, Neil Sass; Scott Nelson from the Iowa Soybean Association; and the producers (Scott and Dylan Ness, Nick Rolling, Mike Johanningmeier, and Derek Bentien).

The first site we stopped at had cereal rye cover crop drilled at a rate of 1-1.5 bu/ac into soybean stubble in mid-October with approximately 7,400 gallons of hog manure injected into the growing cover crop approximately one month later.  After manure application, the injection bands did not have cover crops growing in them, but the rest of the field had fairly even cover crop growth.

Research from ISU has shown that this method can have the same overall biomass when compared to a field without manure application, indicating that the manure helped increase the biomass between the injection bands to make up for the plant mortality in the injection bands.  The research found that cover crop nutrient uptake was higher in the sites with manure application and the corn grain yield was higher on sites with manure application.  Other studies have found that manure injection does not increase soil organic matter, but pairing manure injection with cover crops can increase soil organic matter and the nutrients taken up by the cover crops are less likely to leach and are made available to the next crop as the cover crop decomposes.

We then drove by a site that had cereal rye drilled at a rate of 1 bu/ac into soybean stubble in early October.  Bedded pack dairy manure with long hay bedding was spread on the frozen ground from January-March.  The producer had been concerned that the manure would be too thick for the rye to survive, but a hearty stand of rye came up through the manure.  He also noted that the manure seemed to be breaking down quicker with the rye cover crop than normal, indicating that the increased microbial diversity associated with the cover crop was helping to break down the thick manure.

The third site had approximately 10,000 gallons of dairy manure injected on corn silage ground near the beginning of October.  The site was then vertical tilled and 1.5 bu/ac of cereal rye cover crop was drilled in approximately 10 days later.  The higher seeding rate and drilled establishment method resulted in an even stand with the highest biomass and highest stand count of the sampled sites.

For people wanting to try cover crops, silage acres are a perfect place to start.  The cover crop can get established earlier and have more fall growth, which provides for greater erosion protection.

The fourth site had ½ bu cereal rye and ½ bu wheat broadcast mid-October into soybean stubble.  Approximately 3,400 gallons/ac of hog manure was injected two weeks later.  The weeks in between cover crop broadcast and manure injection had been dry and the cover crop had little to no growth at the time of manure application.  The broadcast method resulted in varied cover crop establishment.  Some areas were almost bare, while others had a good catch.  It was determined that if rain is not in the forecast soon after broadcasting, the seed should either be lightly incorporated or rolled to ensure good seed-to-soil contact.

We drove by the fifth site which had ½ bu cereal rye and ½ bu wheat broadcast on corn stubble.  The cover crop was then vertical tilled to lightly incorporate the seed and hog manure was injected within a few days.  This site is planted to continuous corn and the producer wanted to see if the cover crop helped to break down the corn residue faster.  The cover crop came up well through the corn residue and the producer felt that the cover crop did help to break down the corn residue.  Because of this, he intends to plant directly into the soil after cover crop termination without doing any additional tillage.

Most of the producers who helped host the field day said that they had tried flying on the cover crop in past years but that the results were quite varied and unreliable.  The most popular method of cover crop establishment is drilling due to the good seed-to-soil contact.  These producers all plan to chemically terminate their cover crop, however they plan to terminate at different dates in relation to planting their cash crop.

These sites all show how manure can be utilized on sites with cover crops.  Cover crops will help to reduce nutrient leaching from manure application and reduce surface erosion as long as an adequate stand is established.  If receiving cost-share for cover crop establishment through state cost-share or EQIP, it is important to note that seeding rates are based on pure live seed (PLS) and so rates need to be increased for seed with lower germination rates.  Also, be aware of the seeding deadlines.  Non-winter hardy species need to be seeded by September 9 and winter hardy species need to be seeded by October 21.

If you have questions about how manure and cover crops can work together, please contact the SWCD/NRCS office in Waukon by stopping by 635 9th St NW, call 563-568-2246 ext. 3, or email Sara Berges at sara.berges@ia.nacdnet.net.