Posted: Thursday, December 06, 2012 12:00 PM
John O'Connell/Capital Press
Winter wheat emerges in a dryland field in Caribou County. Growers in Caribou County have taken to conducting their own tillage trials to find the best ways to capture moisture following a dry year.
Farmer worries conditions could cause topsoil woes
By JOHN O'CONNELL
SODA SPRINGS, Idaho -- Some Caribou County dryland growers are conducting personal field trials to find the best tillage practices to maximize soil moisture.
The trial follows a dry year in the region.
For more than a decade, grower Randy Hubbard has sought to save fuel by using glyphosate herbicides rather than tillage to prepare fallow fields for winter wheat -- a method known as chemical fallow.
Hubbard noticed this fall that his chemical fallow fields yielded less than neighbors' crops planted using conventional tillage. He suspects the topsoil hardens in dry years without tillage, preventing seeds from reaching deep soil moisture.
Next season, he'll try three scenarios to draw a comparison -- some acres prepared as usual with glyphosate, others with conventional tillage before planting and the rest with a combination of tillage and glyphosate.
"I've had good luck with glyphosate in the past where we've had plenty of moisture in it. These dry summers I'm not convinced that's the best way to go," Hubbard said.
Seeded in dusty soil, Hubbard's new winter wheat crop initially emerged in spotty stands. The gaps have begun germinating thanks to recent warm weather and moisture, though he estimates his stand is a third thinner than normal.
To optimize soil moisture, grower Sid Cellan will leave an extra 200 acres fallow this summer. He's also stepped up acreage tilled with his deep ripper, which penetrates 15-18 inches into the soil. Cellan has found improved moisture penetration in soil tilled with his deep ripper improves yields by 5 to 8 bushels per acre, though it uses more diesel.
"Most of the people on fields where they've had problems with dryness this last year, they've gone in and deep ripped. It's a great tool. It's just a little more expensive to do it," Cellan said.
He's flagged a 5-acre experimental plot in which he'll till one-third with the deep ripper, one-third with his conventional chisel plow and the rest with a moldboard plow, which turns over straw so it decomposes more completely to reduce disease pressure.
"We're going to have a test out here to see which is the best where it was dry last year and we figure it will be dry again," Cellan said.
Cellan's moldboard plow digs about 10 inches deep, while his chisel plow digs 6 to 8 inches deep.
Though his winter wheat has come up "blotchy" in places, he expects to have a relatively strong stand.
Jerry Brown, an Idaho wheat commissioner representing southeast Idaho, fears a lack of snow cover heading into winter could result in soil freezing deep, thus preventing spring moisture from entering.
Dry conditions prompted Brown to reduce his winter wheat crop by about 20 percent, in favor of spring wheat.
"It's just barely starting to poke through," Brown said. "We still don't have the potential for yields that we normally would."