No-Till Farmer Blog

Our spring in northeast Nebraska was similar to the spring of 2009 where cool, moist (not really wet) weather kept me from killing the cereal rye cover crop in the soybean stubble at an optimal time. A virtually dry last quarter of 2010 didn’t provide much moisture for the aerial-seeded cover crop to get a good start at growth going into winter. Some good snowfall in January and February helped the rye stay viable until 2.5 inches of rain fell in mid-April and got it going.

The 2.5 inches of rain was followed by very cool, moist (but not wet) conditions for 2 weeks that precluded the spraying of glyphosate to kill the cover crop. It wasn’t until May 4 that the weather gave me a shot at it. I applied 36 ounces of 5.4-pound glyphosate (Durango) and 1.125 pints of Surpass (acetochlor), along with a 1.5x rate of water conditioner because of the tough conditions.

My goal is to terminate the cereal rye at 8 inches. Knowing that I was facing 8- to 14-inch-tall rye made me aware of the fact that allelopathy and soil moisture depletion were going to be more of an issue.

I had read on a no-till cover crops listserv over the winter that allelopathy is more severe when the ground conditions are cool and wet. The gentleman blogging said that warm soil temperatures and in-furrow, pop-up fertilizer help corn plants overcome allelopathy.

Having had that experience in a low, wet area that I sprayed in spring 2010 and planted the next day — which was followed by 2 weeks of wet, cool soil conditions, I decided to wait until the soil temperatures warmed up to plant corn this year. The cold, wet soils did seem to exacerbate allelopathy and the corn in that area was behind the rest of the field in maturity and yield.

The area stayed wet through mid-July, so I believe the extended wetness was a factor as much as the rye allelopathy. Had I not been planting non-GMO corn, I would have considered planting and killing the rye after it had taken up more moisture.

I decided I’ll just take the planting season in the order Mother Nature gives it to me. It was already April 29 and I knew I’d have to plant soybeans sometime, so I no-till drilled 250 acres of soybeans, some into a rye cover crop on dryland sand corn stubble that I had aerially applied last fall. Having a GMO crop in the ground makes the cover-crop management a lot easier.

The soybeans are emerging as I write. I drilled them 2 inches deep and got 0.2 inches of rain that night. Monitoring the moisture depletion and the weather forecast, I decided to terminate the rye on May 4. It’s a good thing I did, as heat and wind on May 9 and 10 may have compromised the soil-moisture situation. The sandy soils did not dry out and the beans would have emerged even without the nice 2 inches of rainfall received over the last two nights.

So, back to corn planting we went on May 6, taking it in the order Mother Nature led us. The silty clay loam soils had dried out pretty well with 6 days of warm, windy weather. The soil temperatures were warm and it was time to plant. Knowing it was dry and with no good chance of rain in the forecast, I set the planter deeper to get a minimum 2.5-inch seed depth.

In an area where the helicopter had doubled up the rye seeding and it was 14 to 18 inches in height and very soddy, I kept the saddle tanks on the planter and the seed boxes on the upper half of capacity to ensure that I had adequate weight to cut and penetrate, place the seed at 2.5 inches, get good seed-to-soil contact, and optimally close the seed furrow.

Following 2 days of 90-degree temperatures and wind on May 9 and 10, we went out on May 11 to check for germination. The seed had germinated, with a 2-inch-long radicle and half-inch long mesocotyl. It appears planting would have been successful at typical seed depth, but a nice rainfall of 2.45 inches on two successive nights May 12 and 13 should ensure a nice even stand of corn. The half rate of acetochlor should activate and provide weed control until the floater comes with 35 gallons of 32-0-0, 6 pounds of sulfur and 1 pound of atrazine.

The post herbicide program in the non-GMO cornfield will be Steadfast, Callisto and atrazine. In the areas where the cereal rye was well established, I will look for the opportunity to take advantage of the allelopathic effect and use less or hopefully no post herbicides.

Rain makes us all good farmers. No doubt, the venture would have been more challenging with the cover crops drying out the soil to the extent they did. Now we will sleep easier.

I am quoting an excerpt from one of Dan Davidson’s blogs called, “N Self Sufficiency,” quoting Rafiq Islam from Ohio State.

“No-till is a challenge for the first few years until the operator gets experience and the soil gets acclimated.” Islam added, “No-till farmers face yield reductions right off the bat — 20% to 25% — and those yield reductions last a good 4 or 5 years until the soil adjusts to the new production system. Also, they face compaction issues, weed control problems, wet fields and the immobilization of nitrogen because of the increased carbon being stored in the surface soil.”

This broad statement may be true in Ohio, Illinois, etc… the higher-rainfall states. I have not experienced a yield drag on no-till corn into soybeans in a corn-soybean rotation in semi-arid northeast Nebraska.

I find the generalization excessive and frustrating. I think 20% to 25% is a pretty strong statement, maybe the information should be released with a caveat correlated to the higher yearly rainfall issues combined with poorly drained soils.

Most weed control problems are derived from the producer’s reliance on use of continuous and/or limited weed-control technologies. We still have the old herbicides that work.

Compaction shouldn’t be a problem if the producer has been responsible with tillage use in his conventional-till operation.

Any of you out there care to share your experiences?

Who’d have thought entering the month of June — being more than 3.5 inches below normal precipitation for the year — that in 6 short days we would recover to normal. However, receiving that much rainfall in a short time frame brings an old nemesis into full view.

The often-ignored specter of ephemeral gully erosion rears its ugly head any time there is an overabundance of rainfall. Ephemeral gullies are those flow areas in the mini-watersheds of fields that erode every time there is a runoff event.

They disappear every spring when tillage is performed and reappear again with the first rainfall event that the field soil profile cannot infiltrate and hold. The flow areas wash out as deep as the tillage was performed, and you can usually see the marks from the disc blades in the gully bottom.

I think that this “disappearing act” that occurs with ephemeral gullies is a big part of the reason why farmers don’t show as much concern for them. Spring tillage erases the gully; they reappear with the first hard rainfall. The growing crop canopy then soon “hides” the newly formed gully and at harvesttime the crop residue spread behind the combine “disguises” the problem once again.

The use of cover crops to enhance residue cover in the field after harvest of soybeans or any low-residue crop will go a long way toward reducing the ephemeral gully problem. Anything that minimizes raindrop impact on bare soils and increases water infiltration within the watershed of a field will mitigate the damage that excessive runoff does to flow areas.

The best treatment for ephemeral gullies is a grassed waterway, and there are attractive CRP programs that pay well for entering flow areas into those them. Grassed waterways can be hard to manage with the advent of field sprayers with 120-foot-wide spray booms and custom applicators that aren’t always the most concerned with avoiding the application of herbicides and fertilizers on waterways.

If you are not going to use grassed waterways as your method of addressing the flow areas in the field, it’s imperative that you follow up the annual or biannual reshaping of those areas with vegetative cover. My suggestion is using cereal rye, as it germinates readily, grows aggressively and provides a good stabilizing sod in the flow area.

Take the time to shape and seed those areas in the fall as soon after harvest as possible to give the rye optimal time to establish during this typically lower rainfall time frame.

The continuous no-till systems being applied on an ever-increasing amount of acres nationwide have cut sheet and rill erosion by up to 90%. It’s this 10% we don’t control that eventually leads to an ephemeral gully that impedes planting and field traffic after a few years.

We have experienced for a long time what tilling flow areas and ephemeral gullies provides for results. It’s time to step up our management to the next level and address this problem.

The wet spring of 2010 gives me reason to be optimistic that the rye cover crops in my highly erodible land (HEL) soybean ground will return multiple benefits. Foremost will be the ability to grow excess moisture out of the soil, providing storage in a saturated soil profile for any rainfall received and minimizing the chances of an erosion event due to saturated conditions.

Low areas that usually have the wettest conditions and highest potential for planting problems will be more trafficable and have less potential for sidewall compaction problems. These areas established better last fall because of the good soils and moisture availability. They will be ahead of the hillsides in growth.

This may allow me to get into fields a day or two earlier as well. That could be critical in a spring that looks likely to have a start to planting.

The late planting and slow start of the rye growth due to a cool, damp and cloudy fall will provide a lesson in how much cover you actually need from a cover crop.  Only Mother Nature knows at this point how much growth we’ll get in the next 3 weeks.

In the spring of 2007, we had a 6-inch rain event in the Battle Creek watershed that flooded the town of Battle Creek, causing millions of dollars of damage. One of my rye cover-cropped HEL soybean fields that lays at the top of the watershed sustained very little damage due to the extra protection. I was out planting that hillside a few days after the storm.

A neighbor called me up on my cell phone to ask how it was working and if he should go try it on his ground. I told him you just have to check the soil conditions, reminding him that I was working in a different environment than he was.

The growing rye cover crop will also sequester nitrogen that may otherwise move out of the soil profile in the event of heavy spring rains. Nutrients cycled and carbon produced in the form of plant tissue that will break down and release carbon dioxide through the growing season are a main benefit, also. I have a feeling this “greenhouse benefit” may be one of the more overlooked benefits of cover crops.

As I indicated in my earlier post, there were a lot of 240- to 260-bushels hits on the yield monitor during harvest. After reviewing my yield maps, I can confirm that most of those spikes were in areas where the cover crop established the best.

I also took some soil samples in early May and sent them to the USDA-ARS in Mandan, N.D., where they were examined under a microscope. I have some nice pictures of my very own Vascular Arbuscular Mycorrhizae (VAM) growing in my rye roots. These populations are present in the green rye cover crop at planting time in the spring and expand rapidly into the growing corn plant roots that follow.

The microscopic hyphae from the fungal mycorrhizae colonize the corn plant roots and increase net root mass volume from 10,000 to 100,000 times. Increased phosphorous uptake and the ability to remove moisture from the soil below the wilting point are some of the main benefits of the VAM.

At this time, I consider the erosion control benefits to be the most important. Any soil not lost to erosion counts toward soil building. If I am going to drop $500 per acre into land costs and inputs, I have no problem investing $30 per acre in erosion control.

Excess soil moisture grown out of the soil helps reduce that erosion. Flow areas stay more stable and sheet and rill erosion is minimized so I can make my first trip to the field either a burndown or a planting.

Yield increases due to a healthier and more biologically active soil are the gravy of the system. When you take care of your soil health, it will take care of you in return.

Starting with a dry spring that didn’t allow a lot of extra moisture for cover crop growth, the 2009 crop year proved a challenge throughout the year for management of cover crops in my corn-soybean rotation.

I believe that March was the only month of the year up to and through June that wasn’t below normal for  precipitation. A September and November each with 0.4 inches of total rainfall, along with a cold and damp but not wet October sandwiched in between, then made it a really tough go for the fall-planted cover crops.

Rye cover crops planted into soybean stubble last fall were easy to manage. Using a 1.5x rate of glyphosate as a base rate for killing cover crops in mostly cool spring conditions is a good rule of thumb. I had a 4-day stretch of 80-degree-plus weather where I backed the rate down to 1.25x and then 1x and found out that the lower rates just meant longer to crop death and more soil moisture probably used.

I did have one 60-foot swath of “Roundup Ready rye” this spring. Apparently, in turning around, I flipped the master switch off instead of a boom switch back on. This rye grew to 10 inches before I terminated it with the 1.5x rate on May 1, just 1 week after planting. The rye was originally sprayed April 22 with 80-degree daytime temperatures and planted April 24.

There was no noticeable effect on corn germination from the later-killed rye. I did see more earthworm activity in the later-killed area when I went out to examine the germination and stand.

I haven’t experienced problems with allelopathy in my 19-year continuous no-till fields even though I keep hearing it’s going to cost me up to 20 bushels per acre. I believe the major issue with rye as a cover crop is soil moisture depletion, not allelopathy. I think the biological systems in my long-term no-till may be biodegrading the leachate before it can affect my 2.5-inch-deep planted corn.

I GPS located the swath so I can lay it over my yield maps and I don’t anticipate seeing it show up as a detriment. There were a lot of 240- to 260-yield monitor hits this year and some of them were in that area. The yield map will put the subject to rest.

I also planted rye Oct. 25, 2008, as a semidormant seeding after corn harvest on a dryland sand farm. The stand partially germinated where the 750 drill was able to put the seed in deeper in residue-sparse areas. In spring 2009, the rest of it germinated and there was really no noticeable difference in the growth patterns by the time it was terminated.

Knowing that the spring was dry and there was not going to be extra moisture for the cover crop, I decided to manage the cover crop differently. I drilled the soybeans April 23 while waiting for the rye sprayed in the soybean ground to have some time to translocate and die.

Two small half-inch showers germinated the beans excellently in the no-till system. I waited until the beans were just ready to emerge and sprayed the first shot of 36 ounces of 5.4-pound glyphosate when the rye cover crop was 6 to 8 inches tall. After field scouting, I was able to leave out the 0.2-ounce rate of FirstRate that I usually use to knock out marestail that’s usually getting ready to bolt around that time.

I didn’t realize until later in the year when I was at a crop protection meeting that the rye cover crop had suppressed the marestail in the field. I had never been able to leave out the FirstRate on that farm before. On the corn fields when I did not use a rye cover crop, I still had to use First Rate. I’ll use that $7-per-acre savings to pay for cover crop establishment in the future.

The dryland sand soybeans yielded 48 bushels per acre in a year when we finished the crop year at close to 4-inches-below-normal precipitation. The previous best average of 47 bushels per acre on the farm came in an above-average-rainfall year with good sun and temperatures.

I have to believe the cover crop had a positive effect. The rye cover crops seem to have a more obvious beneficial effect on the poorer soils for me.  Now I just have to figure out how to reliably and cost-effectively get the cover crops started in the fall. More on that in a subsequent blog.