Side-dressing Corn with Liquid Manure Using a Tanker

Nitrogen is a critical nutrient for corn production in Ohio. Liquid manure, especially swine finishing manure, can be a significant nitrogen source in the ammonium form and a potential replacement for commercial fertilizer.

Ohio State University Extension conducted a five-year trial from 2012 to 2016 comparing 28% urea ammonium nitrate (UAN) fertilizer to both subsurface-applied and surface-applied swine finishing manure and dairy manure. The purpose was to determine if manure could replace commercial fertilizer as a side-dress nitrogen source in corn. In these manure trials, a 1,250-gallon manure tanker with a Dietrich sweeps toolbar was modified to travel down 30-inch-wide corn rows. Subsurface-applied manure was placed at a depth of 4 inches. Surface manure was applied by using the Dietrich toolbar held just above ground level.

Manure research trials were conducted over five years at the Northwest Agricultural Research Center located in Custar, Ohio (Table 1 and 2). The swine manure application rate was 5,000 gallons per acre to achieve 200 pounds per acre of ammonium nitrogen. The dairy manure application rate was 13,500 gallons per acre to achieve 140 pounds of ammonium nitrogen. Manure analysis information for each manure treatment is presented in Table 3.

It was assumed that the ammonium nitrogen in the manure was completely available to the corn plant, while one-half of the organic nitrogen in the manure was also available to the corn plant. The dairy treatments received additional nitrogen as incorporated 28% UAN just prior to the manure application to reach the 200 pounds of nitrogen per acre treatment goal. The 28% UAN control treatments also received 200 pounds of nitrogen per acre.

In this trial, soybean was the previous crop each year, and no starter fertilizer was applied to any of the treatments. Pre-emergent applications of 28% UAN, swine manure, or dairy manure were made within three days of corn planting. Stand counts were taken each season, and there was no statistically significant difference between any of the treatments.

Post-emergent applications of 28% UAN, swine manure, and dairy manure were made at the V3 corn growth stage. Post-emergent manure applications were also made with a 1,250-gallon tanker and Dietrich toolbar with sweeps. Incorporated manure was placed at a depth of 4 inches. Surface manure was applied by using the Dietrich toolbar held just above ground level. The surface-applied manure splashed on the corn leaves, but little to no burn injury was observed.

In both the pre-emergent and post-emergent plots, subsurface-applied swine finishing manure treatments outyielded the 28% UAN treatments. For example, post-emergence surface manure application corn averaged 137.5 bushels per acre over five years while subsurface application yield was 26.9 bushels per acre higher at 163.4.

When the manure was surface applied in these treatments, the yields were lower than both the incorporated manure and the 28% UAN treatments. This is probably due to the volatilization loss of nitrogen to the atmosphere. The incorporated dairy manure treatments with additional 28% UAN were similar in yield to the incorporated swine manure treatments.

Side-dressing corn with a manure tanker can provide additional opportunities for livestock producers to utilize manure nitrogen. Side-dressing can begin immediately after planting until the corn is too tall for equipment travel. Corn rapidly uptakes nitrogen at the V7 growth stage, however carefully planned timing is recommended so that side-dressing does not harm the root structure of larger plants which can lead to reduced yields.

Livestock producers have modified manure tankers to travel down rows of corn by replacing flotation tires and rims with extended rims and narrower tires. In Figure 1, a manure tanker has had the wheels widened for use in the corn field.

In addition to the expense of modifying the manure tanker to travel down corn rows, yield losses due to soil compaction may occur. When narrower wheels are used, less soil surface area sustains the weight of the manure tanker, causing greater soil compaction. Adding a Dietrich sweep unit to the area traveled by the manure tanker can, however, alleviate at least some soil compaction (Figure 2). Emerging side-dress technologies may allow side-dressing to be conducted with dragline systems (see Ohioline fact sheet, Identifying Vegetative Corn Stage to Minimize Injury From Using a Soft-Drag Hose During Manure Application (ohioline.osu.edu/factsheet/anr-0210).

Summary

The application of liquid swine finishing manure to farm fields represents a significant annual expense for livestock producers. Applying manure to growing corn instead of purchasing commercial nutrients can offset application costs. The application of animal manure to growing crops can help maximize the utilization of manure nutrients, especially nitrogen. Corn is a crop that needs nitrogen and responds well to manure application.

When applying any manure to corn in Ohio, you should always be aware of setback distances from ditches and streams. This information can be found in the NRCS 590 Nutrient Management Standard (agri.ohio.gov/wps/wcm/connect/gov/3dd2869c-32d2-4dd7-84d7-5c21f2f3b74b/590_OH_CPS_Nutrient_Management_2020.pdf?MOD=AJPERES&CONVERT_TO=url&CACHEID=ROOTWORKSPACE.Z18_M1HGGIK0N0JO00QO9DDDDM3000-3dd2869c-32d2-4dd7-84d7-5c21f2f3b74b-o3TOsXw). In addition to set-back distances, some areas in the state have weather-related restrictions that need to be followed. Contact your local Soil and Water Conservation District (SWCD) office about manure application restrictions specific to your county.

Additional Resources

Ohio Composting and Manure Management, The Ohio State University
(ocamm.osu.edu/manure-management)