CONSERVATION TILLAGE in peanuts is here to stay. That's the observation of John Baldwin, University of Georgia Extension peanut specialist, who cites economics and reductions in time and labor as primary reasons for the recent trend towards reduced tillage peanut production.
“We estimate that more than 20 percent of Georgia peanut producers are doing reduced tillage this year,” says Baldwin. “In 1998, we had about 40 inches of rain in the spring, so many farmers could not get in the fields and do normal soil preparation.
“So, they tried conservation tillage, and many have stayed with it. We probably have twice as many peanuts in conservation tillage this year than we've had for the past five years.”
Most reduced tillage peanuts in Georgia are strip tillage, or Paratill and strip tillage, he says. Some farmers Paratill in the fall, seed the wheat and strip-till peanuts in the spring, he adds.
Improved herbicides and increased irrigation have reduced the production risks for reduced tillage peanuts, notes the agronomist. “Consequently, strip-till is on the rise. The trend is driven by economics, but conservation also plays a role. Machinery and labor savings, in addition to reduced energy expenses, will influence peanut farmers to reduce trips across the field. They also can use less and smaller equipment,” he says.
No one is claiming, says Baldwin, that reduced tillage will increase peanut yields. “Our goal with reduced tillage peanuts is to equal the yields made in conventional tillage. If we can get yields equal to those in conventional tillage, we're substituting tillage operations for chemical costs. Our primary savings are in time, labor and fuel.”
One of the most important factors in successfully growing reduced tillage peanuts is getting a good “kill” on the cover crop, and getting it killed early, he says.
“Most of our growers tend to go with wheat or oats because they are easier to manage than a rye cover crop. The wheat is easier to kill when the grain head is on the plant. Also, the mulch will stay with you longer during the season and will help conserve moisture if you kill wheat at this stage.
“We also recommend that growers have a stubble height of 6 inches or less. Our research has shown that tall stubble can affect peanut yields, especially in single rows. In one study, the pegs actually grew over the wheat, and the wheat held the pegs which were 3 to 9 inches long up in the air.”
Growers need to roll down, mow or kill the cover crop slightly early while there's enough moisture in the cover to make it fall to the ground, he adds.
Baldwin also recommends that growers kill broadleaf weeds in the small grains earlier in the year with 2,4-D. “If we kill the broadleaf weeds at this time, there's no danger to a cotton crop. Also, we can kill cutleaf evening primrose, pusley and other hard-to-control weeds in peanuts earlier in the year, before they become significant problems.”
Growers planting reduced tillage peanuts are almost certain to have more grasses and more herbicide escapes, he says. “If you're planting reduced tillage, you're pretty much dependent on a postemergence grass herbicide. In our plots, we can't seem to get the right watering regime to activate the herbicide. Either that or the cover crop residue is tying up some of the material.
“Reduced tillage will require a higher level of management, especially in controlling weeds. Growers need to be more timely in all of their production practices in a reduced tillage system.”
A good guidance system also is needed when planting strip-till peanuts, he says. “A good guidance system is a must because we are planting ‘on the flat’ when we plant peanuts. Generally speaking, we don't raise beds in strip tillage. Knowing where we're at in the field is important, both for planting and for digging. We need good, straight rows when we're planting. And, if we end up with converging rows at harvest, we know where we're at, especially with twin rows since they tend to have a more flat canopy.”
Peanut producers will gain the most advantages from a reduced tillage system in sandier soils that tend to have higher temperatures and in sloping fields, according to Baldwin.
“Our research has shown that soil temperatures definitely are cooler in reduced tillage systems. Last year, we saw a 1,100 pound-per-acre yield increase in one strip-till field over a conventional field planted in the same variety. Soil temperatures in the strip-till field were 15 to 20 degrees cooler than the conventional field.
“These fields were watered on the same schedule, but the mulch in the strip-till field did a good job of conserving moisture, and there was less evaporation. This year, soil temperatures haven't been excessively high, so we don't expect to see as much advantage as in a year with consistent 95- to 100-degree days.”
Strip-till peanuts also have been proven beneficial in the battle against tomato spotted wilt virus, says Baldwin. This past year, in tests conducted by Auburn University, the University of Florida and the University of Georgia, strip-till peanuts had less incidence of tomato spotted wilt than conventional till peanuts in 33 out of 34 times.