North Dakota researcher discovers differences in wheat phosphorous useWritten by Natasha Wheeler
“About 25 years ago, I observed that some wheat varieties require less phosphorous than others for proper development and growth,” notes Jay Goos, professor of soil science at North Dakota State University.
Before he retires, Goos is revisiting his discovery to unearth further data about phosphorous in wheat.
“I made a list from USDA of wheat varieties that had achieved about 20 percent acreage planting in North Dakota,” he explains.
Seeds were obtained and increased from 47 historical varieties from the USDA inventory.
“We tested the varieties to see which ones require the least phosphorous for the proper growth and development. There are great differences in regards to phosphorous needs in wheat varieties,” Goos states.
Although it might have been expected that the fastest growing plants would require the highest amount of the nutrient, this is not what Goos discovered.
“We did not find that varieties that grow the fastest require more phosphorous,” he says. “What we have found is that the varieties that develop the fastest tend to require more phosphorous.”
These plants, Goos explains, are those that require the fewest growing degree-days to create a new leaf on the main stem.
“Rapid development has more to do with maturity. If it takes fewer growing degree-days to produce a leaf, it is going to head earlier and so on,” he comments.
His data shows that varieties that have more sensitivity to day length, growing more slowly in the spring, tend to require less phosphorous for proper growth and development.
“We have tested the historical varieties, and our next step is to look at about 50 current and future varieties,” Goos adds.
In a typical plant breeding scenario, a grower may not be able to detect which plants require the highest levels of phosphorous, since crops are grown in high quality soils.
“A normal plant breeder wants the best land possible that’s been heavily fertilized so they can find varieties that have the most productivity, and that’s logical,” he states.
But Goos believes that farmers should be as informed as possible about the crops they are growing.
“A farmer is going to grow a given variety for a whole list of reasons, but I think a farmer should know whether that particular variety has a really high need for phosphorous,” Goos comments.
For example, in the 1990s, wheat was plagued by a disease called Fusarium head blight. A wheat variety known as 2375 seemed to be the only one with some resistance to the disease.
“Those farmers were going to grow that variety,” Goos says, “but now we know that variety is one of the biggest phosphate hogs in the world.”
Soil tests show that phosphorous levels are dropping, but fertilizer prices continue to increase.
“It will probably become more expensive in the future because there is a finite amount of rock phosphate in the world,” he remarked.
Farmers hoping to reduce inputs or costs may find Goos’ research to be important when choosing which variety of wheat to use.
“More knowledge is always better,” Goos notes. “This has been a fascinating subject to learn, and farmers seem to be interested in it. Hopefully we can characterize current and future varieties.”