Journal of the NACAA
ISSN 2158-9429
Volume 9, Issue 1 - June, 2016


Wheat Yield Results from Top-dressing with Liquid Swine Manure

Arnold, G., Field Specialist, Manure Nutrient Management Systems, Ohio State University Extension
Douridas, A., Extension Educator, Agriculture and Natural Resources, Ohio State University Extension


Liquid swine finishing manure was applied as a top-dress nitrogen(N) source for soft red winter wheat and compared to urea fertilizer over a three-year study. The manure was applied using a manure tanker and Peecan toolbar at a rate of 117 pounds of N per acre. The urea was applied using a fertilizer buggy at a rate of 110 pounds of N per acre. No statistical yield difference was observed between urea, surface applied manure and incorporated manure treatments in the three year average.  Replacing purchased sidedress N with swine finishing manure at a comparable ammonia N rate can help pork producers get more value from manure.


In Northwest Ohio, corn, soybeans and wheat are the primary crops grown. Soft red winter wheat is typically top-dressed with urea in late March or early April to maximize yields. Liquid swine finishing manure contains ammonia nitrogen (N) that could potentially be used as a top-dress N source for wheat. Utilizing livestock manure in this fashion would save the farmer the cost of purchasing commercial fertilizer and also allow the nutrients in the manure to be applied to a growing crop. Livestock farmers need to apply manure to growing crops, whenever possible, to reduce manure nutrient losses into surface waters. Post-harvest application of manure to wheat and corn stubble is a common practice in Ohio. However, much of the N is not utilized because it is lost before the next crop is planted. The application of manure to wheat could open a new window to apply manure in Ohio.

A four-year study in Wisconsin on corn grain and silage (Talarczyk, Kelling & Wood, 1998) and a one-year study in North Dakota on wheat (Wiederholt, 2009) found that fall applied manure resulted in higher yields compared with spring applied manure. In North Dakota, the highest yield was wheat receiving spring urea. As the spring urea was the highest yielding treatment in the North Dakota wheat study, the potential for spring applied manure as a top-dress N source for wheat in Ohio was worth investigating. This study was designed to determine if the available N in liquid swine manure could provide adequate top-dress N for soft red winter wheat yield.


In each of the three years of this study (2007-2009), liquid swine finishing manure was applied as the top-dress N source and compared to urea in a randomized complete block design with four replications. All manure applications were made with a 5,250 gallon manure tanker equipped with a Peecan toolbar with a width of 13.5 feet. The three treatments applied to growing wheat were: 3,500 gallons per acre of surface-applied swine finishing manure, 3,500 gallons per acre of incorporated swine finishing manure, and 110 pounds per acre of surface applied urea. The urea was applied using a fertilizer buggy equipped with a spreader with a width of forty feet. In the incorporated treatment, the Peecan toolbar opened slices in the soil, approximately seven inches apart, to a depth of four inches and manure was applied directly over each slice.

All treatments were applied to the wheat on the same day each of the three years. Treatments were applied the last week of March or the first week of April each year when the wheat was in Feekes growth stage four to five. The 3,500 gallons per acre rate of swine manure supplied 117 pounds of available N per acre.

Under-floor pit swine finishing manure was used with an average analysis of 33.4 pounds of available N per 1,000 gallons (table 3). Available N is the N available almost immediately for a growing crop and is mostly in the ammonia form.

Manure treatment blocks were 1,500 feet in length and 40.5 feet in width. Urea treatment blocks were 1,500 feet in length and 40 feet wide. The 40 foot width of the urea treatments was the spreading width of the fertilizer buggy. There were four replications each year. The center 30 feet of each treatment was harvested for yield. The ends of all treatments were trimmed off to assure all were of equal length.

The soil type was Hoytville Silty Clay Loam. The soil phosphorus level (Bray P1) was 54 ppm and the potassium level was 172 ppm. The plots were minimum tillage and in a corn-soybean-wheat rotation. This was a non-irrigated field.


The 2007 and 2009 crop seasons produced strong wheat yields in this study. The 2008 wheat yield was well below normal due to a late fall planting season that led to a poorer than normal fall tillering and a thin stand the following spring.

During the first year of this study the surface applied manure treatment resulted in a statistically significant increased yield when compared to the urea treatment and the incorporated manure treatment. All treatments were statistically similar during years two and three of the study. For the three-year average, there was no statistically significant yield difference. The one-way analysis of variance (ANOVA) is used to determine statistical differences between treatments.


Table 1. Wheat Yield Results From Swine Manure Applications.


Yield (bu/acre)





3-year ave.











Incorporated swine manure





Surface applied swine manure










Least Statistical Difference (0.05)





Coefficient of Variability






Table 2. Weather Data (March 1st to June 31st).





Wheat planting date




Normal precipitation (inches)




Actual precipitation (inches)




Historical average temp (F)




Actual average temp (F)





Table 3. Swine Finishing Manure Nutrient Analysis.


Pounds/1000 gallons

Total N


Ammonium N (NH3)


Organic N


Available N


Phosphorus (P2O5)


Potash (K2O)




There was no visible burn damage to the wheat leaves by any of the treatments. The incorporation of the manure did damage some of the wheat stand where the soil slices went through the plants. The plants did not die and the yields were not negatively impacted. Wheat head counts were not taken in any year of the study. At harvest time a weigh wagon was used to determine yields. Moisture tester data was used to adjust all yields to the same moisture.

The tracks made by the tractor and manure tanker during application were very evident in the wheat plots. This seemed to initially stunt the wheat but the tracks became less visible as the crop grew.  The manure treatments appeared to be darker green in the two weeks following the treatments but all treatments looked equally green within three weeks following the treatments.

The liquid manure application cost, using the Minnesota Manure Distribution Cost Analyzer spreadsheet, was calculated at $20 per 1,000 gallons or $.02 per gallon. The cost of applying 3,500 gallons of swine finishing manure as top-dress N was $70 per acre. The N cost for the urea treatments was $60 per acre. Livestock producers must eventually land apply manure produced from their operations. The cost savings, from not having to purchase commercial fertilizer for the wheat, should be taken into consideration when looking at the cost of the manure application.


In this study, liquid swine finishing manure proved an adequate replacement for commercially purchased urea as a top-dress N source for soft red winter wheat.

The use of a manure tanker to apply swine manure to a growing wheat crop is not an efficient process. The heavy manure tanker also raises concerns about soil compaction. The results of this research will encourage research into using a drag hose to apply manure to wheat in Ohio. The drag hose would address both the soil compaction and manure application efficiency issues. The drag hose would also lower the manure application cost per gallon.

Applying liquid livestock manure to growing crops can give livestock producers another window of time to apply manure in-season to farm fields. The application of manure to a growing crop could help capture more of the manure nutrients and reduce loss to the environment potentially improving water quality. There is also great potential to apply liquid manure forages and other small grains.

Literature Cited

Talarczyk, K. A., Kelling, K. A., & Wood, T. M. (1998). Timing of Manure Applications to Cropland to Maximize Nutrient Value. Proceedings for Manure Management Conference, Ames, IA. Retrieved from

Wiederholt, R.J. (2009). Wheat Response to Fall vs. Spring Manure Application. Journal of National Association of County Agricultural Agents, Volume 1 issue 2. Retrieved from