AEN-130

No-Till Notes: No-Till . Soybeans - The Explosion

AEN-130
Authors: Dr. Greg Brenneman, ISU Extension Field Specialist -
Agricultural Engineering, and Mr. Jim Fawcett, ISU Extension Field Specialist - Crop Production
Revised January 1992
Content reviewed 4/95 by Dr. Mark Hanna, Department of Agricultural and Biosystems Enginering

In just the past couple of years, acreage and interest in no-till soybeans has literally exploded. This is mainly because of four reasons. First, is the recognition that equal or better yields can be obtained with no-till soybeans as compared to doing any tillage. Second, with conservation compliance, many producers see no-tilling soybeans as a way to stay in compliance while producing soybeans on sloping ground. Third, is better weed control options with newly developed post-emergence herbicides, reduced prices on some products, and lower rate usage with some products. Fourth, is the increasing use of no-till drills and improvements in their design. Let's look at several of these areas to see what it takes to be successful with no-till soybeans.

Yield Results

For the past 10 years, farmers' experience and research plots have shown nearly identical soybean yields between tillage systems at a given location. Ten years of yield data from the NE Research Farm at Nashua has shown 41 bu/A for a moldboard plow system and 40 bu/A for both chisel plow and no-till systems. In the first two years of a tillage research project at the SE Research Farm at Crawfordsville, no-till soybeans have averaged 53 bu/A while the chisel plow system has averaged 52 bu/A. All of these plots are in 30 inch rows.

Weed Control

While good yields were recognized in the 1980's, concerns about consistency of weed control and herbicide cost with no-till as compared to incorporated herbicides, held many producers back from no-tilling soybeans. With the development of a number of new products and lower costs with some burndown herbicides, several effective weed control strategies have been developed.

A strategy that has worked well through the 80's has been a split application of herbicide with an early preplant (EPP) application in April and a preemergence (PRE) application after planting. The EPP application is made prior to weed emergence and at a time when there is a good chance of receiving rainfall to incorporate the herbicide. Herbicides that have been used successfully include Dual, Sencor/Lexone, Preview, Prowl, and Pursuit Plus. Advantages include more consistent weed control even with variable rainfall, prevention of any weed growth, and a clean field at planting time eliminating the need for a burndown herbicide. Also, if cultivation is going to be done, the PRE application can be banded with the planter thus cutting costs.

A second similar strategy has been to apply an EPP application of Sencor/Lexone, Preview, or Pursuit Plus primarily for broadleaf control. In June, a postemergence (POST) grass herbicide such as Assure II, Poast Plus, or Fusilade 2000 is used to clean up any grass escapes. Advantages include delayed and reduced grass pressure because of the EPP herbicide. This makes the timing of the POST application less critical.

A third weed control option is the use of a herbicide such as Roundup or Gramoxone Extra for burndown prior to planting and then POST herbicides for the remainder of the weed control. In the past several years, use of Roundup as a burndown has increased dramatically. This is because the price has been cut about in half and lower rates have proven effective when applied in a low gallonage carrier. When used alone with a non-ionic surfactant and applied in 3-10 gallons of water, Roundup has provided good burndown at a 0.75-1.0 pt rate. At current prices, this cost is $4.00 to $5.40. While no specific label exists, some producers have added 2,4-D ester to increase the burndown of broadleaves. Another option to improve broadleaf burndown, is using 2,4-DB (Butyrac) which does have a label for use with soybeans. Pursuit, Poast Plus and Blazer/Basagran, or Assure II and Classic/Pinnacle type POST programs are then used for the rest of the weed control. Advantages include just treating for the weeds that come up and normally very consistent control. Because crop canopy development to aid in weed control is important with this type of program, use of solid seeded soybeans is encouraged.

Equipment

Most equipment considerations focus on planting the soybeans. Regular row planters with coulters or trash cleaning disks to handle cornstalks work well. There has also been a great deal of interest in the last couple of years in no-till drilled soybeans.

There are basically two types of drills...those with a coulter caddy and those without. Examples of coulter caddy drills include Great Plains, Tye, Crustbuster and Krause. They have an extra tool bar on the front that carries the coulters. For the most part, the 1" fluted coulters have proven to be the most effective coulter. Planting depth is basically controlled by regulating the depth the coulters run.

The second type of drill is the John Deere 750 drill that has a single, angled opening disk instead of double disk openers. This single disk cuts through residue by itself and does not need a coulter ahead of it. On all drills, adequate weight and down pressure springs are important to get the residue cut and the soybeans planted at the proper depth.

There are several different types of press wheels available...1", 2", and V press wheels. The 1" seem to work the best in most no-till situations. The 2" may have an advantage if the drill is also going to be used in tilled (soft) ground. The V press wheels will plug easier on a drill unless the openers are staggered to provide more trash clearance.

Operating Advice

If no-till drilling, operating at 7-9 mph and running at a slight angle to last year's rows will improve trash clearance. Cornstalks are best left standing and unchopped. This improves trash clearance, traps more snow for improved soil moisture, and does not slow soil warm-up in the spring.

Plant at a depth of 1-2 inches. Too shallow of planting can leave the seed laying in the residue or in soil that dries out quickly. Be sure to actually check planting depth and not rely on planter or drill settings. The layer of corn residue can alter the actual soil depth of planting up to 1 inch.

Well drained soils are the preferred candidates for no-tilling soybeans. Even on wetter soils, the later planting of soybeans as compared to corn reduces any problems of soil warm-up.

On low testing soils, P and K fertilizer can be applied over the corn residue in the spring or fall. On medium and higher testing soils, P and K fertilizer can be applied ahead of the corn crop.

Getting Ready For This Spring

To get ready for no-tilling soybeans this spring, evaluate the following items:

Is your planter equipped with no-till coulters or cleaning disks or do you have access to a no-till drill?
If in row beans, do you plan to cultivate and will your cultivator handle the corn residue?
What are the main weed problems in the fields you plan to no-till? Plan the herbicide program accordingly.
Do you plan to do your own spraying or will you have it custom done? This can affect timeliness as well cost depending on the number of spray trips.

Learn all you can. Talk to producers with no-till experience, check with Extension or SCS staff for no-till information.