The Effects Of Row Spacing And Seeding Rates On Corn Yield Potential - Iowa
This trial was designed to provide farmers in southern Iowa helpful row width comparisons (20- and 30-inch row width systems) on later maturity corn products in Iowa and to help determine the yield response of higher seeding rates within each row width system.
Research Site Details
Five DEKALB® corn brand blends of 110 to 114 relative maturity were planted in two adjacent blocks at two different row spacings and at three different seeding rates within each row spacing:
6-row, 30-inch row spacing planted at 33,000 (33K), 38,000 (38K), and 43,000 (43K) seeds/acre
12-row, 20-inch row spacing planted at 33K, 38K, and 43K seeds/acre
A variable row spacing Case IH® 1215 Early Riser® planter unit was used for all plantings at general planting depth settings.
Both blocks received 150 lb/acre of anhydrous ammonia in the spring. Cultural practices were identical.
Individual plots were approximately 200 feet long.
Understanding the Results
Across all corn products, spraying fungicide offered a 13 bu/ac advantage vs the unsprayed treatment. For this study, a 6.8 bu/ac response was considered a profitable response ($24/ac cost for fungicide application with $3.50 corn).
Fungicide use also increased plant health, as the average staygreen/intactness rating for the unsprayed products improved from 5 to 3 and 6 to 2 (respectively) when both compared to the products sprayed with fungicide.
Fungicide application had a minimal effect on grain moisture, with a 0.6% difference in moisture between the sprayed and unsprayed.