It wasn't too many years ago that soft red winter wheat growers were pleased with yields ranging from 40 to 50 bushels per acre. Today, they are disappointed if several of their fields do not yield more than 80 to 90 bushels per acre, or if the farm average yield dips below 60 to 70 bushels.
Over the past decade or so, average wheat yields in several southeastern states have continued an upward trend because of improved varieties and improved management. Most soft red winter wheat growers now expect yields in their best fields to be as much as twice as high as those achieved just a few years ago.
University and industry agronomists conducting variety tests and plant nutrition studies have documented wheat yields above 100 to 130 bushels per acre in recent years. If wheat yields in these studies — and those yields achieved by progressive farmers — are compared with the recent state average yields, it is obvious there is a large yield gap.
Could inadequate plant nutrition be contributing to part of this yield gap? The only way to be certain that wheat plants receive adequate nutrition is to:
(1) Start with a good soil sampling program; (2) follow the nutrient recommendations based on the soil test results; (3) use locally or regionally calibrated guidance for appropriate nitrogen rates, sources, and application timing; and (4) follow up with plant nutrient analysis to monitor or evaluate the success of the plant nutrition program.
As farmers work with their crop advisers in planning their wheat management programs for the fall of 2006, they may wish to consider these rules of thumb for nutrient uptake and nutrient removal by wheat. A 70-bushel-per-acre wheat crop may take up over 130 pounds of N, 47 pounds of P2O5, and 140 pounds of K2O per acre. On average, a bushel of wheat contains about 1.15 pounds of N, 0.55 pound of P2O5, and 0.34 pound of K2O.
Using known nutrient uptake values and average yield data collected by the USDA National Agricultural Statistics Service for several southern states, we can estimate nutrient uptake or nutrient demand. The resulting values demonstrate a sizeable increase in nutrient uptake or demand in the last two decades.
As wheat yields have increased in the southern states, nutrient removal has also risen. This means that more nutrients have been removed from each wheat field — and from the soil — than in previous years.
These increased yield facts — and the nutrient uptake and removal estimates — clearly illustrate the need to pay close attention to soil fertility and required nutrient application rates.
Select wheat varieties that are adapted to your soils, cropping environment, and management skills. Then, make sure you have a plan in place to achieve your goals and to meet your crop's nutrition requirements. Plan to fertilize your wheat crop for success. Proper nutrient management can help you capitalize on decent wheat prices.
Be effective and efficient in applying plant nutrients this season. Contact your crop adviser, agricultural consultant, or extension agent for more specific soil fertility and plant nutrition recommendations for wheat.