EFFECT OF PARAPLOWING ON CROP YIELDS WITH NO-TILL PLANTING

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.