5 Reasons to No-till Your Soybeans in 2022

September 29, 2021

The Iowa Soybean Association has been seeing a trend toward more tillage in Iowa soybean production. Depending upon your farms, this may or may not be the best decision. Here are five reasons to consider no-till soybean production next year.

1.       Less Costly

Tillage costs money in terms of time, fuel, and depreciation on equipment. While only you can come up with an exact cost for your tillage operation, here are the latest average costs for tillage using numbers from custom operations in Iowa.

Operation	Average Cost ($/A)
Chisel Plowing	17.5
Discing	20.0
Vertical Tillage	18.5
Field Cultivate	15.0
Strip Till	20.0

 

Neither Iowa State University nor the Iowa Soybean Association RCFI has ever documented a soybean yield increase for tilled vs no-till systems in any of our on-farm testing. Unless, you have a special situation, these tillage costs are unnecessary.

2.      Increase Soil Water 

Figure 1 (below) shows the difference in water infiltration time for various tillage systems compared to no-till. Note that reduced tillage systems soak up rainfall much faster than conventional tillage systems, with no-till being the most efficient overall. In recent years, Iowa has encountered many intense storm events with large deposits of rain in a short amount of time. Since no-till systems take up soil water faster, they are able to reduce water run-off from fields and store more water in the soil.

 

Figure 1. Water infiltration rate for various tillage systems. NT= No-till, ST= strip till, DR= disc ripped, CP= chisel plow, MP= mold board plow.

3.      Suppress White Mold (sclerotinia stem rot)

Despite the heat and drought from the 2021 growing season, there were many fields in Iowa that encountered white mold, a serious disease of soybeans. While no-till will not eliminate white mold, the residue helps suppress it by preventing spores from splashing from the soil into the crop canopy. Adding cover crops into a no-till soybean system further suppresses white mold.

4.      Simplify the weed spectrum

While seemingly counter-intuitive, no-till soybeans can simplify the weed spectrum. Tillage operations bring long buried large weed seeds to the soil surface, giving them the opportunity to germinate. In no-till systems, large-seeded weeds such as cocklebur, sunflower and velvetleaf remain buried. Unfortunately, no-till systems are no better than conventional systems for small-seeded weeds such as waterhemp but cover crops can help suppress them with a thick enough stand.

5.       Saves Soil

No-till systems reduce erosion, which is a growing threat across Iowa. According to the Daily Erosion Project at Iowa State University, the average soil loss is about 4 tons/A. We used to believe this was a tolerable rate of loss, but if you do the calculations, 4 tons/A of soil loss per year across a 40-year farming career equates to a loss of 1-inch of topsoil. If you are interested in leaving a legacy for future generations, no-till soybeans are an important addition to your plan.

This article does not assert that there are not problems with no-till soybeans. These systems rely on chemical weed control, which can lead to resistance issues. Some farmers also encounter problems with stand establishment. Figure 2 shows the stand gaps that no-till soybean farmers sometimes encounter. In this example, the crop was planted no-till into cover crops with a high-speed drill. As the drill was not able to handle the residue, seeds were not consistently planted at adequate planting depth. For this reason, we recommend using planters equipped with residue managers, or making special adjustments be made to high-speed drills to achieve vigorous stands in your no-till soybeans.

 

Figure 2. Stand gaps in no till soybeans planted with a high-speed drill.

 

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