Virginia Tobacco Specialist David Reed says going no-till with tobacco has been a long process, but combined with drip irrigation it may be a long-term solution for tobacco growers in the state.
Speaking at the recent Virginia Ag Expo, Reed says he tried no-tilling tobacco back in the early 1990s. “There was so much variability in the soils on the fields we tested, and combined with other factors, like a lack of good no-till equipment, we could never get comparable yields to conventional-tillage,” Reed recalls.
From 1995 to 1997 they conducted another series of no-till and strip-till tests with better results. We could get comparable yields to conventional-tillage, but fuel was fairly cheap back then, and there just wasn’t too much interest among tobacco growers to switch tillage practices, he says.
In the past couple of years Reed has worked with Dinwiddie, Va., growers Mark Spiers and his father Robert Spiers with a new strip-till rig that has produced both comparable yields and significantly lower input costs.
In the same field, Virginia Tech researchers are working with the Spiers on a drip irrigation test. Combined, Mark Spiers says he sees some great opportunity for tobacco growers who are in a position to use both systems.
The strip-till rig, Spiers says, does an intensive cultivation in one pass. It rips the soil under the row and works up a finely prepared seedbed for the transplanters.
Reed says his research interest is in how much soil erosion they are getting from the strip-till system and looking at the cover crops on the soil surface. However, he says, growers working with the system are looking at reducing the number of passes across the field to save money on fuel costs.
In the Dinwiddie test field that Reed works with the Spiers, after strip-tilling and prior to transplanting, there was 67 percent of the soil surface still covered by double-crop soybeans and other residue cover. “Even 30 days after transplanting the crop, we still had 44 percent of the soil covered with residue,”he says
“In the real world, tobacco growers see the benefit of fuel and labor savings in planting and harvesting the crop. That’s the important thing to them. I look at it for the conservation and soil-building qualities they are getting in their soil,” Reed adds.
“Drip irrigation is nothing new in tobacco, we had a few people dabble with it over the years. My original interest was with burley tobacco, trying to find a workable prescription nitrogen program that will deliver the nitrogen as the plant needs it.
Now, we are seeing fewer and fewer tobacco farmers, but larger and larger acreages, which has generated renewed interest in developing prescription fertilizer programs’”he says
In a six-acre field in which Reed works in cooperation with the Spiers, he is able to irrigate the entire field using an 18 horsepower engine that pumps 200 gallons a minute. “Saving money on pumping cost and efficient utilization of water are becoming more important as we seem to go from drought to drought in the tobacco growing areas of Virginia,” Reed says. Using the low horsepower pump and drip irrigation is about one-third the cost of conventional overhead irrigation, he adds.
To bypass running over irrigation tape and headers during cultivation and transplanting, Reed tried putting the tape down at lay-by. It works really well, and we are trying to perfect the system to get the tape closer to the row.
In the past, Reed says, five-eighths inch tape has been the standard size for drip irrigation. In the test at the NAME farm they used both the standard and seven-eighths inch tape. We are seeing rows longer than 600-700 feet and that is maximum size for five-eighths inch tape.”
In tobacco fields with a 6 percent to 7 percent slope and longer rows, there will need to be some more precise engineering applications for maximum performance, Reed contends.
In the Spiers’ six acre field they applied about 30,000 gallons of water or about one-sixth acre inch over the six acre field.
Reed says the current cost of putting down the drip irrigation tape is $400 to $500 per acre. He notes they are looking at more permanent tape, which will probably drive the one-time cost up, but the long-term cost down.
The drip irrigation tape was placed about six inches deep and six inches off the row. Driving a straight row is critical. Should the economics of growing tobacco get better, the use of GPS-guided systems that are used extensively to apply drip irrigation in high value crops can be used efficiently in tobacco fields.
On flue-cured tobacco the yield benefits of irrigation have been varied. On burley tobacco, he says, the yield increase clearly pays for the cost of drip irrigation. “In one test in burley in southern Virginia we increased yield from 1,900 pounds per acre to 2,800 pounds per acre,” Reed says.
“A big advantage of the system we are using with the Spiers is convenience. If you want to irrigate, you just turn the valves on, turn the pumps on — you don’t have to set up anything,” he adds.
“We have had very dry weather throughout this year’s crop. We’ve irrigated our other tobacco acreage with tow-hose systems three times, compared to one with the drip irrigation. The tape looks small, but in four to five hours we can irrigate this six acre field with a lot less work and costs than using our conventional irrigation system,” Robert Spiers says.
As tobacco fields in the Southeast increase in size and the labor supply continues to diminish while fuel and input costs soar, growers are going to have to turn to more efficient farming practices to stay in business.
For tobacco growers with an available water supply, the combination of strip-tillage and drip irrigation looks like a good combination.