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No-Tillage Sweet Corn

Steve Groff

Successful no-tillage sweet corn is more than just bolting a coulter on your planter. It involves knowledge of how the system works, correct equipment, and experience.

How the System Works

The foundation of this system is the establishment of a cover crop in late summer or in the fall. My favorite for early sweet corn right now is hairy vetch that is planted in late July. The vetch will grow up to 2 feet tall and then winter kill, providing a nice dead residue to plant the early sweet corn into. A few weeds are generally present so 1/2 - 1 pint of Roundup is applied either with 1.5 quarts of Bicep and 1 quart of simizine or as a separate pass. If broadleaves break though I will use 1/2 ounce of Permit or Basagran. For the later plantings I will plant into a mix of hairy vetch (25 lbs.) and rye (30 lbs.), straight hairy vetch (25lbs.), or straight rye (2 bu.). I have successfully no-tilled sweet corn into corn and soybean residue with excellent results, however more herbicides and fertilizers are needed to control weeds and provide N. I credit rye/vetch giving #50lb. of N and straight vetch #75lb. of N. Vetch seed is expensive so I grow my own and sell the excess.

I wanted to control covers mechanically and in a way that flattens them near the soil to help their decomposition. I ended up buying a 10-foot Buffalo Rolling Stalk Chopper in 1996. It's designed to flatten and chop cornstalks, on a scale between a flail mower and a disk. The machine has two rows of rollers, four in front and four in back, with eight 23-inch blades per roller. The turning rollers crimp up the cover and push it right down. I added parallel linkage so each roller floats independently. It can be run at 8-10 miles per hour, so it's fast and economical.

It is important to roll the cover before wind blows it in various directions so it is laid parallel to the direction of planting. However, I generally do not let rye grow over 2 feet where I intent to plant sweet corn as it has a negative effect on the growth of sweet corn. After sweet corn harvest, I use the rolling stalk chopper to roll down the stalks and immediately plant another cover crop.

I use a customized Kinze no till planter with Monosem row units to seed the sweet corn. This machine has Rawson coulters, Martin row cleaners, Yetter parallel linkage, Martin spading closing wheels, Keeton seed firmers and foam markers. When planting early into the dead mulch I use a 2" eight wave coulter on either side of the row and clean the row so the soil dries out and warms up quicker. It is basically a zone - till setup. Later on I change the coulters to a 1" 13 wave style. Each setup applies 80lbs. of liquid N on the row - 40 lbs. on each side. I also put 3 gallons of popup fertilizer in the seed trench.

Fertilizer management evolves, as you have become more committed to the use of no-till, cover crops and the overall concept of sustainable ag. Any synthetic N I use is mainly ammonium sulfate. I need the sulfur it supplies, as well as its low volatility. I side-dress by broadcasting 40 - 80 lbs. of dry N (depending on contribution of cover) when the corn is 8-12" tall. I do some foliar feeding as well.

Soil Compaction is to be avoided at all costs! However, once you've no-tilled for several years the soil becomes noticeably less susceptible to compaction. Cover crops are key to this in building soil structure. I'm real fussy about when lime and manure trucks can get on my fields. If you ever need to alleviate compaction, do so with as little surface disturbance as possible. I have a customized 2 shank Unverferth ripper/stripper to go through my field driveways after harvest. This tool has a narrow shank that penetrates 12 inches deep and has a 2-inch wide wavy coulter on either side of the shank. This keeps soil from being thrown away from the shank and chops it up a bit. A 12-inch wide rolling basket follows to further break up clods. I am able to plant behind this without needing to disk.

Controlling perennial weeds can be a challenge in no till but I have found that with intensive crop rotation and occasional spot spraying, weeds can be managed effectively.

No-till plastic layer

2 years ago I purchased a Samco plastic layer (made in Ireland) and converted it to work in my no-till conditions. I move my rows in on the planter to plant 18” double rows and then cover 2 rows with the photodegradable plastic. Herbicides are applied as the plastic is laid. This has worked well- after a lot of trial and error- and allows me to grow sweet corn that matures 7-10 days earlier.

Here are some proven systems that you might want to consider that treat the soil better then full tillage.

Zone tillage is a 2 or 3 coulter in-row setup that goes before the planter either as a separate pass on its own coulter cart, or on the planter itself. It tills an area 4-8" wide and 2-4" deep. Some farmers use the coulter cart a day or 2 before planting as a way to dry and warm the soil. I know a 150-acre sweet corn and pumpkin grower from Maine who uses this system quite successfully. It really shines in the cool wet soils of early spring. Usually no other tillage is used.

Strip tillage has shank or knife with a coulter in front to cut residues. It is more aggressive than zone till and can go 3-6" deep and creates a tilled strip 6-8" wide. Sometimes it is used in the fall in a way that makes a slight mound in order for drier and warmer planting conditions in the spring

No tillage is what I do. It leaves the residues on the soil surface and I try not to disturb any more soil then necessary to get the plants or seeds in the ground. Has the greatest savings in erosion potential, reduces the need of equipment and fuel, and if done correctly is the best for increasing the soil quality on most soils. The disadvantages are trying to overcome cold and wet soils in the spring and getting the right equipment to do the job.

Deep tillage is only needed when the subsoil is compacted. It's better if you can do it with an implement that will leave most of the residue on the surface. It's best to avoid causing the compaction in the first place if you can.

Farmers who desire to reduce tillage have some proven options to choose from. Learn all you can about how the system works, make necessary equipment changes, and start on a small acreage.