- Prices paid for sweet corn are low relative to the cost of producing the crop, and every strategy possible must be used to maximize net return. Two strategies used to enhance profitability but that have received little research attention under Western Oregon conditions are the use of pop-up fertilizers and increased plant populations. Despite indications that popup fertilizers improve early-season growth, concrete evidence that these fertilizers ultimately enhance growth and yield are often lacking. Seeding density also can be increased to improve crop yield up to a point, but intraspecific competitive ability and the competitive stress tolerance of varieties currently produced in the Willamette Valley are poorly understood.
In a single stress test of plant density on sweet corn growth and yield in 2014, popup fertilizer treatments had little impact with the exception of the variety Captain at the highest plant population on 40,000/A. The response of the two varieties differed slightly as plant population increased. Fresh ear weight, kernel yield, and gross return peaked at 40,000 plants/A for the var. Captain at 36000 plants/A for the var. 1477. Conversely, as plant population increased, ear length and width decreased slightly. Kernel yield followed trends very similar to fresh ear wt.
Costs associated with changes in plant population were estimated to be $69 and $99 for the varieties 1477 (@36000/A) and Captain (@40000/A), respectively, when accounting for the additional costs of greater planting densities. The additional costs associated with increased plant density lowered the adjusted gross return by 5 to 6%, but the value of corn at the optimum density still averaged $131 to $181/A more than the standard of 28000/A.