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Research Highlights

Research Highlights
Profitably Incorporating In-Season Liquid Manure Applications

Checkoff-funded research shows liquid manure can be applied in-season to growing soybeans without yield penalty up to the V5 stage.

By Barb Baylor Anderson

(adapted from Ohio Field Leader)

More livestock production systems manage liquid manure today rather than solid manure, which opens new opportunities for using available liquid manure as fertilizer in soybeans. In fact, liquid manure has physical properties that make it conducive for in-season application to a growing crop and not just as a surface application once soybeans are planted and prior to emergence. 

In Ohio, manure traditionally has been applied during the summer after wheat harvest, in the spring prior to planting corn and soybeans, or in the fall after harvest.

“The vast majority of liquid manure in the Western Lake Erie watershed is surface applied in the fall now, given the loss of wheat acres in Ohio. That results in most of the nitrogen and a portion of the phosphorus being lost since there is no growing crop,” says Glen Arnold, Ohio State University manure nutrient management field specialist and principal investigator for the Ohio Soybean Council-funded research. “Changing weather patterns and increased rainfall events also contribute to the need to find application alternatives. There is a huge bottleneck in the fall.”

Arnold says plenty of manure is available. Much liquid manure storage has been added, along with more application capacity and expensive equipment that is used to move manure.

But can liquid manure be successfully applied in soybeans later in the season without causing crop damage or yield loss? Arnold set out to find answers. 

He notes as alternatives have been explored, sidedressing corn with liquid manure has become more accepted. Equipment has been modified to reduce crop damage, and the switch from liquid tanker to drag hose application has reduced soil compaction and improved efficiency.

“Manure is currently being drag hose applied to corn up to the V4 growth stage,” he says, noting research has shown any injury from the drag hose up to this stage does not have a yield penalty.

However, the drag hose could pose potential risk for soybean injury or damage. Arnold tested that theory using a 30-foot-wide toolbar dragging a 35-foot manure hose. 

Manure was applied at two locations at three soybean growth stages: V3, V5 and V7. Both fields saw minimal visual damage from the dragline at V1 through V3, so Arnold concluded liquid manure can be drag hose applied to single or double-crop soybeans up to V5. At V5, a small curve developed in plant stems about three inches above the soil surface with no apparent harm. 

Physical damage became noticeable at V7. Most of the soybean plants were partially broken off at ground level but continued to grow and produce pods with little negative yield impact. 

“The purpose of the research was to see if we could use soybean fields as an option if we needed a place to go with manure application in-season and not negatively impact the final yield due to injury from the drag hose,” he says. “We would not expect a yield increase, year in and year out. Soybeans like moisture, especially in dry years, and liquid manure is about 97 percent moisture. Other benefits from the manure applied to soybeans include not only the nitrogen, but also the phosphorus, potassium and micronutrients that manure contains.”

“Checkoff dollars we invest in plant research help equip soybean farmers with the practices, tools and technologies they need to defend against yield robbers, while improving the yield potential and quality of our soybeans,” says Todd Hesterman, Ohio Soybean Council Research Committee chair and Henry County soybean farmer.

To find research related to this Research Highlight, please visit the National Soybean Checkoff Research Database.