Cover Crop Selection

Cover crops are being widely promoted and slowly adopted. Farmers don’t doubt the benefits covers play in soil health, but often question the economic prospects of planting one and if there will be a return.



Since cover crops are still the exception, here are seven reasons to plant cover crops. 

1.       Cover crops can help you implement a no-till system.

2.       Cover crops can help reduce erosion by improving aggregate stability.

3.       Cover crops support soil microbial activity.

4.       Cover crops can help with weed control. 

5.       Cover crops help build soil organic matter.

6.       Cover crops can reduce the need for commercial fertilizers.

7.       Cover crops can extend the grazing season for livestock.

As with any new practice, you want to do everything possible to make it successful. Selecting what will work best with your operation will support your decision to use cover crops. Often, we hear suggestions that you should first decide what you want the cover crop to do, but that may be difficult as one of my clients said, “I want it to do everything.”



One of the big things to focus on is to increase soil microbial activity. Soil microbes drive the soil system.  The more microbes we have, the more we release nutrients, and the more we promote aggregate stability. There are many microbial products on the market, but why not grow your own? Multispecies mixes will best support microbial activity. Each species added to the mix promotes different microbes.  Five or more species would be considered ideal. Nitrogen-fixing species should be part of the mix, too. There can be pitfalls to growing a lot of different crops so you might want to consider something simpler to start with.



Extending your grazing season sounds simpler. Lots of producers like to graze turnips in the wintertime.  This a good choice because the cattle love them. Ideally, turnips should be planted by early September.  How do you do this? Fly them on or use a high clearance applicator adapted to seeding. Sounds expensive? Maybe you can start with cereal rye or triticale drilled after harvest. Both are suitable for winter grazing and both are also suitable for green chopping in the spring.



Maybe you want to start by growing your own nitrogen. Legumes are the way to go. Crimson clover, red clover and hairy vetch are popular choices. One traditional way to use clover is to plant it in a small grain crop in spring. Then after harvesting the grain, let it grow out for hay. Next spring, once again it needs to grow into May to maximize nitrogen production. Hairy vetch or clover may be planted into soybeans aerially or by high clearance equipment by September 1. It should also grow into May to maximize nitrogen fixed and stored in the soil for the next corn crop.    



If you want to open your no-till ground to increase water infiltration and improve root penetration, you may want to try oilseed radishes or annual ryegrass or maybe both. Radishes experience winter-kill, so that is a bonus. Annual ryegrass can be difficult to kill, so work out how you plan to terminate it in spring.



Some producers like to keep it simple by planting cereal rye or triticale after corn. Soybeans can be planted or drilled either before or after termination. A simple cover after soybeans is oats and radish. It winter-kills and can be easy to plant into in spring. Oats and radish should be flown on or planted into early maturity beans after harvest.



Consider soil health testing to provide yourself with some scientific data to prove that you are accomplishing what you want to with cover crops. Run a before test and another maybe two or three years down the road, and notice the difference you will see.



There are way too many options to cover them all in this short blog. Michigan State University maintains the Midwest Cover Crop Tool, which is a good place to start when picking your species of cover crop to plant. Don’t be afraid of choosing a more complicated mix, but do your homework on how to make it work. Contact us at rpmsoils.com 

Road trip Effingham

I made a short road trip to Effingham today to do a septic tank evaluation.  Most of the corn along the way was pollinating or past pollination, although not in some of the uneven parts of fields.  Some fields are starting to run out of nitrogen.

Soybeans looked better than corn.  We had a lot of rain earlier in the week and the soybeans were putting on a lot of top growth.  Two issues that will cut into yields at this point are weeds that were starting to show through, and poor stands.

Zombie Weed Apocalypse

By: W Kevin Nelson, CCA 4R NMSSenior Agronomist, Prairie Agronomics, LLC 

The growing season of 2019 just keeps on giving. Without going over all the morbid details, let’s just say that it’s been challenging from the very beginning, and looks like the challenges will continue on through to harvest and beyond.

As we get into the latter part of summer we are still contending with weeds that have refused to die. For lack of a better term, zombie weeds. These weeds have had burndown herbicide treatments, pre-emergent residual treatments, one or more post treatments, and still refuse to die. Some are newly emerged, some have just not succumbed to the programs we had planned before the spring weather went off the tracks. And now they have gone to seed, or soon will.

At this point, another spray trip becomes little more than an attempt at revenge. The plants are way above label size restrictions, and have hardened off with the dry conditions of the last few weeks. The chances are they won’t die, and the seed on them is probably already viable to bring on the next generation.

Am I going to give you the solution to the zombie weed apocalypse? Probably not. But I’ll point out that this weed control disaster isn’t a failure in any one program or system. We can find fields under all types of management that is experiencing problems, owing mainly to the conditions of the growing season. What I will say is this: start right now addressing the weed problems that will probably be coming our way in 2020.

Since many, though not all, weed control systems now combine seed traits with herbicide products, now is the time to start putting those combinations together. These systems must start with variety and hybrid selection, and seed companies will be on your doorstep early this fall. Choose a system that fits your needs from a production standpoint as well as weed control ability.

Consider cover crops to suppress weeds this fall. Some cover crop mixtures are better than others at keeping weeds down, and the consideration on how to terminate these crops needs to be factored in. Seed supplies may be an issue, as well.

Talk to your retailer about a fall burndown treatment. This can make a tremendous difference in weed pressure in the spring. With what looks like an extended harvest, it is crucial that you make your plans and let your retailer know with plenty of time what you intend to do.

So as you look out over your fields, frustrated with the zombie weeds poking through your crops or covering your Prevented Planting acres, remember that they aren’t coming after your brains, but you will need to put your brain to work now to prepare to hold them in check in the coming seasons.

Corn Harvest in Brazil

By Euardo Paim:

 Here in MT we are harvesting corn and the yields are very good! In an average harvest we harvest 90 bags of corn per HA, this year the yields are at 135 bags of corn per HA. In some regions we had rain breakdown, but it won't be a big problem

Managing Micro-Nutrients in Soybeans,

Written for IL SoyAdvisor,  

Are you paying enough attention to all the nutrients your crops need?

Byline: Dave Rahe

Topic: Nutrient Management

There are 18 essential nutrients [JF1] in plants: Nitrogen, phosphorus and potassium are the most likely to be added as fertilizer. Water, carbon and oxygen come from air and water. Calcium, magnesium and sulfur are needed in large amounts as well, and in Illinois we generally take what we get from nature.  Sulfur now commonly needs to be added along with the big 3. We add calcium and magnesium when we lime, although in Southern Illinois we generally come up short on magnesium in our liming materials. And micronutrients are also essential, but needed in smaller amounts. Boron, iron, manganese, zinc, copper, chlorine, molybdenum and cobalt are generally considered essential micronutrients and round out the 18. Some would add silicon to that list as well. 

The first step in getting your micronutrient levels in order is to get your soil pH right. Soil pH affects the availability of all plant nutrients, but in order to keep micronutrients available, pH needs to be in the sweet spot between 6.0 and 7.0. The chart above is from Michigan State University.

Once soil pH is corrected, the next step is to soil test for micronutrients. It is surprising how many people still say that testing is not needed for micronutrients. In the modern world, it costs very little to get the extra data. Another rub is, micronutrient testing is thought to be unreliable in determining a plant or yield response to soil test levels. My response is that you need to start somewhere. 

If you still want more data, I have found tissue sampling to be useful in determining whether micronutrient deficiencies exist. Last year, I had some soils with relatively low manganese test levels, but by tissue testing, I found that manganese wasn’t an issue. Tissue sampling in soybeans is done at R-1 or R-3 growth stages. North Central States has a publication on Managing Micro-Nutrients for Soybean Production in the North Central Region.

A few cautions are in order concerning tissue testing:

·        Time of day sampled can make a difference.

·        Sometimes dust on the plant can skew results.

·        Don’t test when the crop is stressed. Of course, it will show deficiencies, but the plants are unlikely to respond to treatment.

After collecting your data and determining you have a problem, what do you do about it? First off keep in mind that micronutrients can be toxic if over applied. Soybeans are especially sensitive to boron.  Copper can be toxic at as little as 10 ppm. I work on some soils where copper is over 100 ppm caused by industrial pollution, which is very difficult to manage.

Many researchers report that a blanket application of micronutrients without some indication they are needed isn’t economically wise. If treatments are needed during the growing season, foliar applications can be effective in treating symptoms. I have also found that soil applied micronutrients can be effective in treating low soil test levels. Sometimes soil test levels remain at desired levels for several years after treatment. I suspect we are stimulating microbes who will consume and then recycle micronutrients back into the soil. 

This leads to the question about biological treatments for micronutrients. One of the reasons that pH between 6 and 7 is so important is that it is ideal for microbial activity. But the big question is, can I improve micronutrient availability by using one of the new biological seed treatments? I think biological treatments can work, but it seems to be on a farm by farm and year by year basis, so if you want to try biologicals, you should also be prepared to do some strip trials to see what works on your farm.

There are also some farmers using silicon as a fertilizer. Silicon is one of the most abundant elements.  The building framework of our soils is alumno-silicate clays. There should be enough available in most soils, however some trials have shown a good response to fertilizer silicon. The downside is that we have little idea on response or economics and currently there is no soil test for available silica. To learn more about this element click Silicon Fertilizer Gaining Ground.  

In summary, micronutrient deficiency isn’t a common problem in soybean production, especially when pH is maintained between 6 and 7. Soil and tissue tests can be useful in identifying micronutrient issues, and microbial treatments may be useful as well. Finally, keep your eye on silicon as an emerging fertilizer. 

Crop Condition

I have read recently that we should expect the  third largest soybean crop ever this fall.  I realize a 30 mile loop through Montgomery County is not the whole midwest, but at least in this area, there is no chance for an above trend line crop.  The picture below is showing an average looking crop at best.  Soybean growth stages almost all look like they were planted as double crops.  To make matters worse, stands are very spotty as well.  Yes, some people will be patching some in, but that will not make the yields jump much. 

The corn crop is showing stress as well.  the wet yellow areas from las week are now showing as green and rolled up.  All the corn I saw looked like it could use a little shower.  I would venture the moisture is there, but shallow rooted crops are not getting through the compacted soils to get what they need for vigorous growth.  The picture below shows the gamut of corn condition.  Stands are very uneven and we know that cuts into yields.  We are still seeing yellow corn in ponded areas that will not recover.  

Also, it is now pretty easy to see the prevent plant acres.  While we know that the Mississippi and Missouri River Bottoms will not get planted in many areas, we can now see upland areas that will not get planted too.  The windows for planting were just too small.  

Spring Soil Sampling

Soil sampling has traditionally been done in the fall, after crops are harvested. The objective is to know how much fertility the soil already has to produce next year’s crop. 

But in my business, more than half my sampling is done in the spring. We usually begin sampling when fields are planted or ready to plant and continue until crops are no more than 12-inchs tall to minimize damage to the crop. I have found ATV damage to be minimal at this stage. The photo below shows corn has recovered a day after sampling.

  

One of the reasons for spring sampling is that the soil moisture and temperature conditions are usually more consistent in the spring. Moisture and temperature when soils are sampled can affect soil test results. That is the reason that experts agree you should sample at the same time of year every time you sample. In fall, soils can be dry and/or cold. I have seen potassium results as much as 75 pounds per acre lower when sampled dry as opposed to sampling later after soil is moistened by rain. I have not been able to find any problems with sampling wet soils if you are not cutting ruts. 

Another advantage to sampling in spring is that results and recommendations can be ready before harvest to allow for earlier fertilizer purchase and more timely application. Application can follow the combine. With fall sampling, there is usually a delay between harvest and getting results. 

Frequency of sampling is also an issue in the fall. The Illinois Agronomy Handbook says that once in four years is enough. The problem is that variations in crop yields because of dry or wet conditions may be difficult to account for when sampling only once in four years. We sample every year or two to take the guesswork out. If you base your fertilizer application on removal rates, keep in mind that your crop does not read the removal charts and removal is often more or less than the charts say. 

No matter when you sample it is important to use proper techniques to assure consistent results. A soil probe and bucket are essential tools. Sample depth should be 7 inches in order to assure that your pounds per acre of nutrient is calculated correctly. 

I like to sample in management zones, but the zones can be difficult to define for some people. Using USDA SSURGO data can be a place to start, but I find that about half the time it does not suit my needs.  I like to use the five factors of soil formation to help me determine where the lines are between the zones. The factors include climate, organisms including vegetation, relief (or topography), parent material, and time. Yield maps can sometimes be used to determine zones. Some scientists like to use a Veris to measure electrical conductivity, which can define zones. I usually divide the field into major landforms and then subdivide to get 8- to 11-acre zones. I pull 10 to 15 cores over the zone to put less weight on old spread gaps and overlaps. Zones can be smaller if needed. 

If you grid sample, you should still make sure the grid point defines the part of the field sampled. Avoid waterways or anomalies. Also, to avoid the old spreading gaps and overlaps, be sure to go 10 to 15 feet from your ATV and maintain that distance as you walk in a circle pulling 8 to 10 cores. There is a good bit of research that supports the need to pull many cores. 

This illustration from Michael Dunn of Anez Consulting, LLC in Little Falls, Minnesota, shows how grid sampling can distort what is in the field.  It is used by permission. 

Samples should be air dried. It is OK to use a fan but avoid heat over 125 degrees Fahrenheit. 

Many people are considering switching corn acres to soybeans. One consideration is crop insurance.  Check with your agent for help sorting it out. You may have a soil consideration with saturated soils if you have applied nitrogen for corn. Denitrification can occur fast on saturated soils. If there is nitrogen left, you may want to plant corn. You should soil test to see how much nitrogen remains in the soil. Your pattern for nitrogen sampling should assure that some of the cores are from the knife track and some are from the in-between areas. I get good results sampling a foot deep, but the University of Illinois says to sample 2 feet deep. Samples need to be spread out and fanned so they dry in 24 hours. You can also use an in-field nitrate tester, but they will miss the ammonium form of nitrogen. If you know you are not wasting nitrogen applied, you may not feel bad about switching to soybeans. If herbicides have been applied, make sure they will not cause a problem either. 

The bottom line when growing soybeans is that you need to make sure that your fertility levels and fertilizer applied will support the high yields desired.