The move towards reduced-tillage peanuts clearly has become more than just a passing fad in Georgia, with more than 20 percent of the state's growers planting in some form of conservation-tillage this year.
As expected, economics and reductions in time and labor are cited as primary reasons for making the switch, says John Baldwin, University of Georgia Extension peanut specialist. Some growers, he says, turned to reduced-tillage out of necessity in 1998 and have stuck with it.
“We received about 40 inches of rain during the spring of 1999, and many farmers couldn't get into their fields to do routine soil preparation,” says Baldwin. “Some of the growers tried conservation-tillage, and many have stayed with it. We probably had twice as many peanuts in conservation this year than in the past five years.”
Most reduced-tillage peanuts in Georgia are in the form of strip-tillage or Paratill and strip-tillage, notes the agronomist. Some farmers Paratill in the fall, seed the wheat and strip-till peanuts in the spring.
Improved herbicides and increased irrigation have reduced the risks of planting reduced-tillage peanuts, says Baldwin. “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 their trips across the field. They also can use less and smaller equipment,” he says.
Reduced-tillage peanuts have not been proven to increase peanut yields, emphasizes Baldwin. “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 in the field 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 six 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 three to nine 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 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.”
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.”
Best in sandy soils
Peanut producers will gain the most advantages from a reduced-tillage system in sandy 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.
“Those 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 in Alabama, Georgia and Florida, strip-till peanuts had less incidence of tomato spotted wilt than conventional till peanuts in 33 out of 34 test plots.