Renewable Farming

Consultant Bob Streit: Focus on cover crops, residue management

Field Thoughts on Cover Crops:

The 2015 fall harvest season is mostly completed in the western half of the state and progressing slowly in the eastern half. Later planting and having time consumed by livestock chores takes a good bite out of each for farmers in that area. There have been many acres of corn stubble chiseled under already, turning the ground partially black.

The fields planted to cover crops have turned green from the rye or mixtures planted in each. In contrast to previous years, the rains came in time to facilitate good germination and most have taken off and seem to be growing taller each day. The plan on what to do in 2016 with cover crops will be determined by their operation and to whether or not they have livestock.

Those with cattle could take the foliage as silage or bales. Those without cattle get to decide how to terminate the crop. The farmers who have used the rye or turnips or other mixes in previous years have generally seen an improvement in soil texture and moisture infiltration rates. In fact in the just published Progressive Farming magazine they had a big series on what they wrote about changing climate which they proceeded to use logic to claim it was real. Thus they said the proof was in the fact that there were more 1.25” rainfall events, which was the amount where the water no longer soaked into the soil. Does that mean that Gabe Brown, who is the defacto leader in using cover crops, has been living with a different climate, since his soils can and has absorbed an 8” rain with no erosion or runoff?

In 2016 there are likely to be growers faced with the decision of what crop to plant that might lose the least money. Bankers may force that choice, as we know that no good ground in the Midwest has ever sat idle unless it was due to flooding. This is where a cover crop could be left to mature with the hay penciling out as good as a row crop due to lower input costs, depending on cash rent terms.

Most farmers who have been raising cover crops and have studied their effect on soil biology and nutrient scavenging would like to find a spray mixture the does not involve any or as much hard chemistry. So far those that appear promising are based on either P or S fertilizer mixed with a good surfactant and perhaps a small dose of Kixor. I did hear of a new soft product that could come in from another source that may be greenhouse tested this winter. The other possibility for termination would be to use a roller and plant the soybeans into that mat of rye.

People who used that method liked what they saw, but recognize planting dates and variety of rye help to determine when they do the rolling successfully. What I saw with it last year is that slugs, snails and millipedes can then become economically important crop pests. Some insects always find a niche that fits them.

Now that the corn growers group has hired people to investigate the issue of soil health, they need to use the Haney Solvita test to determine how much if any effect the different termination products or methods have on the soil biology.

Residue Management

Most years the worry is about what to do with the woody corn stalks left in the fields. This year fewer of those stalks remain solid, so they should disappear quickly. Much of the bacterial or fungal decomposition has already occurred. This may offer an opportunity to spray a biology mixture on the residue to decompose it and to increase nutrient availability next season. That would reduce the need for applied fertilizer. I have seen this happen, leading to increased oxygen levels in the soil which increased microbial populations. This is an area where Jill Clapperton and Gabe Brown can teach many of us how. If we take care of the underground biology, the beneficials will help feed the crops.

Some of those mixtures can be brewed up in an on-farm tank, where the largest expense is the air pump and the food/mineral mix to grow the microbes, which must be purchased. The system is easy to set up and plumb once you see it.

Iowa’s new Cellulosic Ethanol Plant

This week marked the grand opening of DuPont/DOE cellulosic ethanol plant. It was built for about $225 million just east of Ames on old Hwy 30. The feed source has been and will be crop residue collected within about twenty miles of the plant. When the decision was made to build the plant, the thought was that eventually perennial crops such as switch grass and miscanthus would make more sense as feedstuff since they are perennials costing less to grow while minimizing or eliminating erosion. Different mixtures have been experimented with at the BioResearch Farm west of the ISU campus along with different means of extracting any oil or byproducts.

One question: The original goal was for hydrogen to fuel a percentage of the nation’s vehicles. Hydrogen must be compressed to a high PSI to be stored, and those tanks would have an explosive nature. Thus ethanol became the easily handled, non-explosive material that could serve as the hydrogen source. So will the original thought about hydrogen vehicles be resurrected using new technology that has been developed? And are we supposed to have vehicles that could get extremely high mileage if that is not in the cards?  

Testing for compaction

Now is the time to do field tests with a penetrometer to determine if any owned or long term rented ground has a compaction problem which must be remediated with an inline deep ripping or cover crop program. The best way to drought-proof a crop is still the same: Develop a deeper root system and increase moisture infiltration.

Last week was also the first time most fertilizer suppliers allowed ammonia applicators to operate as the soil temp dropped below 50 F. With the warm temps this week that soil reading likely was raised. How that might affect things is that each big fertilizer supplier is aware of the DMWW lawsuit and realizes every supplier is under increased scrutiny to manage N as good as possible. That means the use of stabilizers should increase as well as more applications being made closer to the time of crop uptake. Newer or soil friendly stabilizers will now find a home.

Nov. 15 — Bob Streit Boone, Iowa 50036 515-709-0143