December 16, 2021
TRIAL OBJECTIVE
The success of dryland corn production depends upon growing conditions and the management strategies employed by the farmer. To help maximize yield potential, the availability of soil moisture on rainfed acres is always an important factor.
Dryland farmers have no control over how much moisture the environment provides through rainfall. However, through management practices they can greatly influence how much moisture is retained by the soil, is available to the crop, and how the limited water can directly impact yield potential.
RESEARCH SITE DETAILS
| Location | Gothenburg, NE | ||
| Soil Type | Hord silt loam | ||
| Previous Crop |
Soybean | ||
| Tillage Type |
No-til and Conventional |
| Planting Date | 5/11/21 | ||
| Harvest Date | 10/25/21 | ||
| Potential Yield (bu/acre) |
160 | ||
| Seeding Rate (seeds/acre) |
15K, 20K, 25K |
The trial was a randomized complete block design with four replications of the seven treatments.
The planter was a fully mounted 4-row, 30-inch planter units utilizing Precision Planting® DeltaForce® for downforce control and Precision Planting® vDrive® for seeding rate control.
A base fertilizer application of 25 lb/acre Nitrogen (N), 50 lb/acre Phosphorous (P), 21 lb/acre Sulfur (S), and 0.2 lb/acre Zinc (Zn) was broadcast with stream bars across all treatments on April 13, 2021.
A sidedress application of 60 lb/acre N was made on 6/21/2021.
No insecticides were applied.
Plots were combine-harvested.
Grain moisture content, test weight, and total weight were determined.
Statistical analysis for Fisher’s LSD was performed.
Table 1. Treatment Systems (greyed blocks are system treatment changes from previous treatment)
UNDERSTANDING THE RESULTS
Yield
Yield was impacted by the system treatments; the lowest yield occurred with the Base Treatment (Figure 1). The Base Treatment was conventional tillage with no residual herbicides which resulted in considerable weed pressure (Figure 2).
The Residual Treatment, which used residual herbicides at planting and at V7 growth stage increased yield significantly (Figure 1) and decreased weed pressure (Figure 3) over the Base Treatment.
Yields for the Seeding Rate Treatment (conventional till, 20,000 seeds/acre, residual herbicides applied) and the No-till Treatment (20,000 seeds/acre, residual herbicides applied) tended to have higher yields than the Residual Treatment which was planted at 15,000 seeds/acre and used residual herbicides (Figure 1). The yields of the Seeding Rate, No-till, and Residual Treatments were significantly more than the Base Treatment (Figure 1).
The 115 RM DroughtGard® Hybrids, VT Double PRO® RIB Complete Corn Blend product used in the Tough Acre Treatment provided significant value to the system by increasing yield by 14 to 16 bu/acre over the Seeding Rate and No-till Treatments, respectively (Figure 1).
With the use of a 115 RM DroughtGard® Hybrids, VT Double PRO® RIB Complete Corn Blend product, the Enhanced Rate Treatment with a seeding rate of 25,000 seeds/acre demonstrated a 5 bu/acre average yield advantage over the Tough Acre Treatment with a seeding rate of 20,000 seeds/acre (Figure 1).
The residual herbicide applications for the Enhanced Rate Treatment (Figure 4), Tough Acre Treatment, and Out of Place Treatment (Figure 5) kept weed growth in check.
Figure 1. Average yield for seven rainfed corn production systems. Gothenburg, NE 2021.
Figure 2. The Base Treatment (conventional tillage and no residual herbicide) experienced considerable weed growth and had the lowest average yield of the seven systems in the trial. Picture taken August 28, 2021 at Gothenburg, NE.
Figure 3. The Residual System, which used residual herbicides applied at planting and V7 growth stage, demonstrated much improved weed control and the average yield was significantly higher compared to the Base System. Picture taken August 28, 2021 at Gothenburg, NE.
Figure 4. The Enhanced Rate System, which increased the seeding rate to 25,000 seeds/acre, had the highest average yield of the seven systems in the trial; however, the average yield was not significantly different compared to the Tough Acre and Out of Place Systems. Picture taken August 28, 2021 at Gothenburg, NE.
Figure 5. The average yield of the Out of Place System was not significantly different than the average yields of Enhanced Rate and Tough Acre Systems. Picture taken August 28, 2021 at Gothenburg, NE.
KEY LEARNINGS
Farmers can realize a significant increase in yield for rainfed corn when the whole system is managed. There was a 41 bu/acre difference between the Base Treatment and the Enhanced Rate Treatment that incorporated good weed control, no-till, good corn product selection, and enhanced seeding rates.
Farmers should work with their local seed sales team member to select a corn product that best fits their field system along with selecting a herbicide program that provides good weed control of the problematic weeds in their area.
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