1987 - Volume #11, Issue #5, Page #33[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story | Read this issue]
Modified Sweep Plow Busts Up Packed Subsoil"It causes little disturbance to the soil surface but does a better job of subsurface tillage than a chisel plow," says soil scientist Lloyd Mielke at the University of Nebraska who, along with ag engineer Leonard Bashford, modified a standard 5-ft. sweep plow to fracture compacted subsurface soil layers.
The big 5-ft. wide sweep plows normally are used to till dryland wheat acres at 1 to 2 in. below the surface. Mielke and Bashford add four 6-in. long shanks to the bottom of the big sweeps and then pull them a ta 3 to4-in. depth at speeds up to 5 mph. "It gives us a double layer of tillage both above the sweep and down to 6 in. below for a total of 9 to 10 in. of tillage. The only disturbance on the surface is a 1¢-in. slit from the sweep plow shank," says Mielke.
Tests on the modified plow were carried out on 45% clay soil near Lincoln. Mielke thinks the idea should work in all but the heaviest gumbo soils. He says it may be particularly suited for minimum or no-till farmers who want to occasionally break up soil without disturbing surface residue. Because of the way the modified sweep lifts the top layer of soil and fractures layers below, it greatly increases water retention, reducing erosion. For tests, the researchers pulled a 3-sweep plow ù 15 ft. in total width ù with a 145 hp. tractor at 4¢ to 5 mph and didn't quite have enough power. "A slightly larger tractor would let us pull at even higher speeds for increased fracturing of the soil," says Mielke.
The four shanks were welded to the bottom of the sweep at a 15? slant toward the rear. Part way down their length, the shanks are twisted 15 to 18? in the direction of travel. Mielke says the twist increases the soil shattering potential of the shanks.
For more information, contact: FARM SHOW Followup, Lloyd Mielke, USDAARS, University of Nebraska, 121 Keim Hall, East Campus, Lincoln, Neb. 68583 (ph 402 472-1514).
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