Higher plant populations
In the higher yielding fields, higher plant populations and 18-inch rows produced 20-30 more bushels per acre than the other treatments. Yield across the multiple test sites ranged from 160-260 bushels per acre.
The risk to the benefits of high plant populations comes from the bad — when plants are stressed from lack of nutrients and the ugly — when plants are subjected to long periods of hot, dry weather.
THE BAD — reducing stress
The North Carolina State corn specialist says seeding rates also affect plant stress. It is not by chance that both corn yields and seeding rates have gone up year-by-year over the past few years. New hybrids coming on the market, Heiniger explains, are much better at handling stress.
Taking advantage of the yield potential of high plant populations is critical from a production standpoint, but to most farmers production and costs all come in the same package — risk.
Managing stress in the corn plant often equates to managing financial stress for the grower. Planting high cost seed at high rates and getting less than optimum yields to pay for the seed and the multitude of other production costs, isn’t good for human or plant stress.
Corn seed costs average more than $200 per bag, pushing average seeding cost for 40,000 plants per acre to near $100 per acre. However, some hybrids are selling for $250-$300 per bag, pushing seeding cost for high population acreage to well over $100 per acre.
Starter fertilizers can be a critical factor in getting any corn crop out of the ground and growing, but is especially critical when trying to maximize the value of growing 35,000 or more corn plants per acre.
Establishing a good root system is the first line of defense against stress, Heiniger says. He adds, “A stronger, larger root mass helps the plant combat stress as well as absorb nutrients more effectively.
Seeding rate affects stress. Stress affects production. Getting seeding rate right is, as Heiniger says, right behind variety selection as the second most important decision a corn grower makes.
The North Carolina State University corn specialist says there are at least four factors any corn grower should consider before selecting a seeding rate:
• Know the hybrid you are planting and how it responds to plant populations.
• Know the water-holding capacity and/or irrigation needed for maximum response.
• Know the proper levels of P and K for your soils.
• Know the competition factors and the stress levels these produce in your crop.
THE UGLY — yield robbers
You can’t control the weather, but you can impact on how the weather affects the performance of a corn crop, especially heat and drought. And, you can manage disease-related leaf damage with a number of highly effective fungicides currently on the market.