26 / www.FarmProgress.com – October 2011 Dakota Farmer Crops Subsurfer incorporates dry manure By DON McCABE I S it the next-generation manure applicator, or is it limited to only poultry litter? That remains to be seen, but the Subsurfer prototype garnered a lot of interest at the North American Manure Expo in Norfolk, Neb., in mid-July. Designed by Dan Pote, a USDA Agriculture Research Service soil scientist, the applicator is one of the first to incorporate dry manure — poultry litter — into the soil. Heretofore, manure injection and incorporation have been limited AUGERS ON BOARD: These parallel augers in the bed of the Subsurfer bring the material forward and help in pulverizing it. Key Points ■ USDA soil scientist develops a prototype tool to incorporate dry manure. ■ Most of the research has been done using poultry litter. ■ The applicator was demonstrated at the Manure Expo in Norfolk, Neb. to the liquid or slurry variety. Pote, based in Boonville, Ark., spoke at the expo and demonstrated the implement, applying dry feedlot manure in it for the first time. The Subsurfer is not commercially available, but prototypes built by BBI, a Cornelia, Ga., company, have been tested in Chesapeake Bay states in the Northeast. In tests in Southern states, it incorporated poultry litter on pastures, although some work has been done on no-till corn. The applicator comes with a box that can hol d up to 5 tons of poultry litter. Parallel augers in the bed draw the manure forward and pulverize it, then drop it through tubes between double-disk openers in front of the box. The incorporation components are corn planter units, with no-till coulters, double-disk openers and closing wheels. Changing speed of the augers changes the application rate, according to Pote. “There is very little disturbance [in a pasture], with only a small slot created. It’s deep enough to prevent the poultry litter SOIL INCORPORATION: This Subsurfer prototype was demonstrated at the North American Manure Expo in Norfolk, Neb. In a short demonstration, it incorporated dry feedlot manure into the soil. from running off the field. It’s also deep enough to prevent most nutrient losses.” In the research, Pote found that the subsurface application of litter lowers nutrient runoff and ammonia emissions by at least 90%. It also was shown to increase forage yields slightly. “The only way to apply dry product in the past is to surface apply it, leaving the potential for runoff or nutrient loss,” he said. Tom Way, an ARS scientist in Auburn, Ala., has developed a different prototype of a poultry litter soil incorporator for row-crop use. He can adjust Strip Till Expo shows how to save time and resources M By JONATHAN EISENTHAL ORE than 200 farmers attended the Minnesota Strip Till Expo last month in Owatonna, Minn., and had the chance to observe nine different strip-tillage systems. The University of Minnesota Extension and Riverland Community College sponsored the daylong event. One Minnesota farmer got into strip tillage more than a decade ago and likes how it revives the soil, returning it closer to its natural state. Plus, it is less work. Success with strip tillage, he said, depends almost entirely on the structure of the berm created by the coulters that follow the shank on the tillage machine. Some machines create a quasi-ridge, while others leave a small depression along the strip. There are adherents for both. Another farmer, Tim Dritz from Lincoln County, Minn., said less fuel, reduced phosphorus and potassium inputs, and less wear and tear on the equipment all appealed to him. He uses strip tillage on the lighter soils at his farm in Hendricks. However, heavier, wetter soils pose more of a challenge to get planted in a timely way, so he still goes with conventional tillage on those acres. U-M Extension educator Brad Carlson, who organized the expo, has been studying strip tillage since 1999. He said that more operators who do strip tillage use precision agriculture technology and methods. These can improve yields and give the farmer a better understanding of “how money moves through his operation.” “GPS autosteer gives that comfort level to plant right on the strip,” Carlson said. University of Tennessee strip-till research found a 7-bushel-per-acre increase when RTK-type technology was used. Most farmers who do strip tillage do their own fertilizer application, rather than hiring it out to a cooperative or custom operator, Carlson said. With that level of control, it’s easier for farmers to customize fertilizer product mixes and rates when working with yield and profit maps. He noted that strip tillage reduces soil erosion because two-thirds to threequarters of the field remains covered with residue. “Raindrop impact is easy to overlook,” Carlson said. “But each drop that falls and hits the soil loosens some particles. Multiply that by millions of drops and you can have a major effect. With the residue in place, the raindrops don’t impact the soil.” Jodi DeJong-Hughes, also a U-M Extension educator, said studies confirm and quantify numerous benefits to this conservation-tillage method. Strip tillage takes an average of five passes, as opposed to nine required for both chisel plow-disk ripper cultivation and moldboard plowing. It also saves the farmer an average of $25 an acre in fuel and machine costs. She noted that, though strip-tillage equipment is a little less easy to come by than conventional equipment, there are at least 18 different manufacturers out there, with machines ranging in price from $15,000 to $120,000, making strip tillage a technology that’s available to farmers across a range of incomes and scales. “Fuel use is reduced, repairs are less, and total machinery ownership cost falls,” said Gene Kuntz, a farm business management instructor at South Central College. An ideal seedbed Agronomically, strip tillage improves water infiltration the first season. Within three to four seasons, it changes the soil condition and creates a mellower soil that makes an ideal seedbed, DeJong-Hughes said. She showed the results from a strip-till study of corn on corn at five southern Minnesota locations over a number of years that showed yields kept on a par with other tillage methods. A noon-hour panel discussion featuring four farmers offered practical advice for operators. The discussion attracted both seasoned farmers and those considering getting into strip tillage for the first time. Bruce Ponwith, a farmer in Cleveland, row spacing with his implement. Chris Henry, University of NebraskaLincoln Extension engineer and cochairman of the expo, said the Subsurfer performed well in a short demo. The manure was scrapped off the pad in a nearby feedlot and was drier than feedlot manure would normally be, he said. Henry said the commercial application of feedlot manure on a large scale below the soil surface is several years down the road. He believes feedlot manure would need to preconditioned in some way, either by composting or by use of a device that removes large chunks of the product. CHECKING OUT STRIP TILL: Scores of farmers turned out for demonstrations and classes at the 2011 Strip Till Expo last month in Owatonna, Minn. Minn., does a combination of ridge- and strip-till cultivation. In the fall, he takes one pass with a ridge cultivator and then a second with the strip tiller to place fertilizer, and then he’s ready to go next spring. He has been able to reduce P and K, starting at 75% of broadcast rates and slowly dropping it lower from there. “Getting fertilizer just where I want it is huge,” Ponwith said. He has seen far less nutrient loss in wet years when using his strips-on-ridges technique. “I get better yield in those wet years, and it’s more environmentally friendly.” Luke Scherger, a Dodge Center, Minn., farmer, said he has seen a 10- to 20-bushel increase by getting fertilizer placed exactly where plants need it. “I like having to do fewer passes across the field, and the benefits to conservation by having the residue,” said John Bonde of Nerstrand, Minn. “I like to see the soil develop its own natural drainage.” Eisenthal writes from St. Paul, Minn.