5/4/2013 7:00 AM
By Carol Ann Gregg Western Pa. Correspondent
BUTLER, Pa. — Dairy farms across the state have been cooperating with Penn State on a three-year study of cover crop trials that has just been completed.
At the Bergbigler farm, eight different seed combinations were planted to find what would work best on this Butler County farm. The plots were replicated four times.
Leroy and Mary Bergbigler, and their daughter Mary Beth farm about 300 acres and milk about 100 cows. The farmstead has both flatland near the buildings and rolling hills on another farm. Bergbigler currently plants wheat on his corn silage ground.
Penn State conducted the study over three years on small dairy operations that grew corn for silage.
“We used fields where the farmer had harvested corn silage,” said Sjoerd Duiker, Penn State soils expert. “These fields traditional have been left bare through the winter.
“These farms were selected because they grew corn for silage and had manure available,” he said.
The study was conducted to find what would encourage farmers to use cover crops without the “stick” of fines or the “carrot” of incentive payments.
The goal was to find what cover crops save nutrients from the soil that would have been lost over the winter to leaching and soil loss.
Cover crops take up the nitrogen and phosphorus that is in the soil and return the nutrients in the spring when the crop is burned down and left to provide nutrients for the next crop. Cover crops also reduce the runoff of soil and nutrients into streams.
The plots were tested for total biomass produced by the various plant combinations. Most of the combinations included a grass and a legume. One plot included tillage radishes. Tissue cultures were taken to determine how much nitrogen the plants took up.
“The farmers wanted to know if they could use the cover crops for forage, so we tested the plants at a higher point on the plants and tested for forage quality,” Duiker said.
The plots showed that when two species were planted in combination they provided more total nitrogen than if they were planted alone.
“I like to learn new things,” Bergbigler said about having the plots on his farm. He hasn’t determined whether he’ll use one of the seed combinations on his farm in the future or which one.
“I still have things to learn from these plots,” he said. “I want to know how they will react when I spray and what yields I get from the corn I plant.”
“Two factors impact production, climate and fertility,” Duiker said.
Variability from site to site in the study was attributed to these factors.
Duiker recommended that seed selection be from seeds grown in climates similar to where the forage will be grown.
“If the seed comes from Virginia or North Carolina it may not be winter hardy enough to survive Pennsylvania’s cold weather,” he said.
Bergbigler is anxious to see how the plots perform from now through harvesting of the corn crop he plans to plant there.
The Penn State study was funded by a USDA-NRCS Conservation Innovation Grant.