For the last 30 years, agronomist Charles Mitchell has struggled for a way to encourage a more even cropland distribution of poultry litter, away from the poultry-producing regions of Alabama where it’s least needed, to areas throughout the state where it is critically needed.
The impending phosphorus shortage may solve this once and for all. Spiking phosphorus prices may finally force producers to take a serious look at this phosphorus-rich source.
Whatever the case, Mitchell says farmers can be virtually certain of one thing: The shortage will likely change forever the way they buy and apply fertilizer.
Along the way, farmers will develop an even keener appreciation for environmental stewardship practices, Mitchell says. He says they’re going to discover that much of the phosphorus they’ve applied in previous years was unnecessary.
“We’ve really preached — and we have research to show — that once soil test phosphorus reaches a high level that crops don’t respond to additional phosphate,” says Mitchell, an Alabama Cooperative Extension System agronomist and Auburn University professor of agronomy and soils.
Those days when many producers opted for 13-13-13 fertilizer over 15-0-15, even though they were reasonably sure they had adequate soil levels of nitrogen? Gone — or, at least, soon will be — blown away by prevailing economic winds as phosphorus shortages play out in world markets.
"Phosphorus used to be cheap and readily available. Growers knew that they could put it out without hurting the crop," Mitchell says. “Up to now, it’s been a case of, well, they might see a response and it’s good insurance.”
It is insurance they no longer can afford, he says.
Yet, it is not going to matter anyway because extra phosphorus has not been shown to increase yields, Mitchell says.
Plenty of work to do
Make no mistake about it: Alabama still has work to do in the phosphorus department. Soil testing reveals a mixed phosphorus picture throughout the state.
“We have some counties, for example, Cullman, in which 58 percent of samples tested very high or extremely high in phosphorus,” Mitchell says. “On the other hand, only about 10 percent of samples from Perry County tested very high or extremely high.”
This high contrast between Cullman, a poultry producing area, and Perry County underscores the longstanding under-utilization of poultry litter throughout much of the state, he says.
Despite these challenges, Mitchell is confident supply and demand factors will soon work to promote a wider distribution of poultry litter throughout state as phosphorus supplies tighten.
“Up to now, we’ve tried to encourage more growers throughout the state to use more Alabama poultry litter and nothing worked until phosphorus prices hit a dollar a pound,” he says. “Then suddenly, we got more poultry litter moving around the state.”
Even so, fuel costs, along with phosphorus prices, ultimately will determine how this is played out, Mitchell says.
While spiking phosphorus prices will not likely increase conservation-tillage usage, Mitchell says they will instill producers with a higher appreciation for the no-till practices that have been adopted within the last 15 years.
“We’ve gotten away from conventional-tillage because of the soil erosion and we know that with soil erosion, you use phosphorus too.
“One advantage with no-till is that the phosphorus is held in place — it’s concentrated and plant roots can get it.”