No-till acreage has expanded rapidly in the past 5 yr in the U.S. Corn
Belt, Yield potential often improves with no-till planting on well dr
ained and low organic matter (OM) soils, but no-till yields are someti
mes at a disadvantage on dark, poorly drained soils. Restricted plant
rooting due to increased soil density is sometimes reported with no-ti
ll planting. Deep tillage with a Paraplow(1) (Tye Co., PO Box 218, Loc
kney, TX 79241), leaving most surface residue undisturbed, was evaluat
ed on three soils in Indiana for continuous corn (Zea mays L.), Annual
paraplowing and biennial paraplowing were used with no-till and moldb
oard plow systems. On dark, poorly drained silty clay loam, annual par
aplowing improved stand, growth, and yield, compared with traditional
no-till planting. On a silt loam soil with 2% OM, response to paraplow
ing for no-till was variable and on a 1% OM soil, paraplowing did not
improve no-till yield. Carryover effect from biennial paraplowing for
no-till planting was not consistent, even on silty clay loam, Paraplow
ing did not improve plowed yields on any of the three soils, Paratilli
ng was also used on four rows of each 12-row plot in the 15th year of
a long-term tillage study on silty clay loam soil. Plow, chisel, ridge
, and no-till systems were used in continuous corn, corn after soybean
[Glycine mar (L.) Merr.], soybean after corn, and continuous soybean.
In no-till continuous corn, there was a positive response to paratill
ing, but yield for no-till plus paratilling was significantly lower th
an plowed yield. With conditions similar to conditions in these studie
s, deep soil loosening is likely to improve no-till continuous corn yi
eld on dark poorly drained soil, but is not likely to improve yield on
well drained or low OM soils where traditional no-till is well adapte
d.