University of Arkansas Division of Agriculture scientists concluded, during a recent field day, that conservation tillage for winter annual forages helps beef producers improve their profits while meeting water quality standards enforced by the Environmental Protection Agency.
The field day at the UA Livestock and Forestry Branch Station at Batesville, Ark., featured research by animal scientists, agronomists and agricultural economists, said Don Hubbell, resident director of the station.
Research began in 2002 and compares the performance of fields that have been conventionally tilled — the soil was turned over with disk and chisel plows — with fields that have had reduced tilling or no tilling, Hubbell said. The tests measured the effects of the different tilling systems on soil characteristics, erosion and runoff of nutrients; the performance of cattle grazed on the winter forages grown on the test fields; and the economic impact on costs of maintaining the pastures and returns on the sale of cattle.
“We're most concerned about runoff of nutrients,” said Merle Anders, agronomist from the UA Rice Research and Extension Center at Stuttgart, Ark.
Rain simulator tests demonstrated that more than half the water ran off fields that were tilled conventionally. Less than 14 percent of the water ran off no-till fields. “The water that doesn't run off goes into the ground,” Anders said. “Water in the ground is available for the grass, and that can be especially important in dry years.”
Runoff water also tended to move organic matter and phosphorus, the main nutrient of concern for water quality in Arkansas, he said.
“Conventional tilling leads to movement of soil, organic matter and nutrients,” Anders said. “That causes variability, which leads to fertilizer applications that put too much nutrient content into some areas and too little in others, and may lead to nutrients running off into groundwater sources. The no-till and reduced-till soils are more stable.”
He said conservation tillage prevents the problems associated with conventional tilling and lowers management costs, particularly for fuel to run tractors over the fields.
“You're risking a lot when you start tearing up the soil,” Anders said.
Stacey Gunter, animal scientist from the UA Southwest Research and Extension Center at Hope, Ark., tested the nutritional value of wheat and rye used for winter forage crops He said the grazing quality of winter small-grain forage crops — wheat and rye — was as good for no-till and reduced-till fields as for conventionally tilled fields.
Another UA animal scientist from Hope, Paul Beck, determined that the performance of stocker cattle on small grain forages grown in conservation tillage fields was equal or superior to those on forage in conventionally tilled fields.
“We saw more total gain per steer on no-till than on conventional-till fields,” Beck said. “We saw the same trend in gain per acre, with no-till coming out significantly better. In part, this may be because there were more grazing days on the no-till.”
The bottom line, according to agricultural economist Brad Watkins of the Rice Research and Extension Center, is that conservation tillage is profitable for production of small grains forage in Arkansas.
“The average expense per acre for establishing and managing the forage was highest for the conventional-till fields and lowest for the reduced-till fields,” Watkins said. “The highest return was for the no-till fields and the lowest return was for the conventional-till fields.”
He said the higher weight gains experienced by cattle on the no-till fields appeared to be the single most important reason for the higher returns.
Fred Miller is science editor for the Arkansas Agricultural Experiment Station. e-mail: firstname.lastname@example.org.