Applying liquid manure to emerged corn with a soft-drag hose requires an understanding of corn development and an accurate identification of the corn’s vegetative stage. Using a drag-hose system to apply liquid manure to a corn field is faster and more efficient than using a manure tanker, and it poses less of a soil compaction concern.
A common way to stage vegetative corn is the leaf collar method. In this method, each stage is defined according to the uppermost leaf with a visible leaf collar. The leaf collar is located at the base of an exposed leaf blade and appears as a light-colored band around the stem. The number of leaf collars visible indicates the vegetative stage (i.e., one leaf collar visible is the V1 stage). Figure 1 illustrates a corn plant with three leaf collars visible indicating it is at the V3 stage.
At the V5 stage, the growing point of the corn plant is still below the soil surface and the plant is less vulnerable to injury from a manure drag hose.
Table 1 includes average plant stand and yield for a five-year field study at the Northwest Agricultural Research Station in Custar, Ohio. The study’s objective was to determine what stand damage and potential yield loss may occur when a soft hose is dragged through corn at all vegetative stages up to the V5 stage. A 6-inch-diameter drag hose filled with water was pulled across each plot twice (moving in opposite directions for each pull) at the assigned corn stage (V1, V2, V3, V4, or V5). The second pass of the drag hose was to maximize the drag hose damage. Also to maximize damage, the hose was dragged in the morning hours when corn plants are the most brittle.
The experimental treatments were replicated four times and randomized in a complete block design over the five crop seasons. For comparison purposes, one treatment did not involve the use of a drag hose.
|
Year |
2014 |
2015 |
2016 |
2017 |
2018 |
2014–2018 |
|||||
|
Corn stage |
Stand |
Yield |
Stand (plants per acre) |
Yield |
Stand |
Yield |
Stand |
Yield |
Stand |
Yield |
Five-year average |
|
No drag hose |
30,166 |
145.1 |
31,850 |
167.2 |
28,625 |
145.1 |
35,000 |
164.5 |
30,750 |
217.8 |
167.9 |
|
V1 |
29,660 |
154.3 |
31,750 |
166.1 |
28,625 |
149.5 |
35,125 |
161.5 |
31,500 |
218.0 |
169.9 |
|
V2 |
30,166 |
157.9 |
32,000 |
165.3 |
28,500 |
141.2 |
34,750 |
159.6 |
30,750 |
217.7 |
168.3 |
|
V3 |
28,933 |
153.9 |
31,375 |
172.3 |
29,250 |
144.4 |
34,875 |
172.1 |
29,625 |
215.6 |
171.9 |
|
V4 |
29,264 |
149.7 |
31,375 |
164.3 |
27,500 |
152.1 |
33,750 |
166.5 |
28,750 |
209.1 |
168.4 |
|
V5 |
15,366 |
109.8 |
23,500 |
123.5 |
16,000 |
126.3 |
25,250 |
122.2 |
18,250 |
132.8 |
122.9 |
The results show that corn can be flattened with a drag hose through the V4 stage without substantial stand or yield reduction. Where the corn was dragged at the V5 stage, the stand reduction was 7,000 to 10,000 plants per acre and the five-year average yield reduction was approximately 45 bushels per acre. The plant stand reduction indicated a loss in corn plants with near-normal ears. At the V5 stage more than one-third of the corn plants were snapped off and replaced with suckers without reasonable ears.
This study was repeated over three seasons using a 4.5-inch-diameter drag hose instead of a 6-inch drag hose, using the same treatments recorded in Table 1. The results mirrored those of the 6-inch-diameter drag hose. The smaller diameter drag hose did the same damage at the V5 stage as the 6-inch-diameter drag hose. When using a drag hose on emerged corn, the corn will flatten but will recover and resume upright growth.
The corn field must be firm to use a drag hose. No-till fields, fields with growing or killed cover crops, and tilled fields that have been packed by rain usually work well. Deep-tilled fields with loose soil are not suitable for a drag hose as the hose will scour the field and pile up the soil. This results in corn plants being buried or pulled from the ground.
Liquid manure is commonly applied to emerged corn in Ohio with a drag hose, but the equipment travels at an angle to the corn rows. The more advanced the corn growth stage, the greater damage to the plants run over by the tractor tires. Driving over corn at the V2 or V3 stage does not seem to be as damaging to the stand as driving over corn at the V4 stage.
When applying any manure to corn in Ohio, 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)