Non-Peer ReviewedThe effect of deep tillage on soil conditions and crop growth was studied over a 5-year period, involving 15 farm sites, 4 soil zones, and both Solonetzic and Chemozemic soils, as well as Solonetzic/Chemozemic intergrades. Deep ripping reduced soil bulk density for up to 2.5 years for Solonetzic soils and for up to 1.5 years for non-Solonetzic soils. Soil loosening by para-plowing was much less dramatic than that of deep ripping and involved only one site (Solonetzic soil), where the effect lasted only up to 1 year. Deep ripping of Solonetzic soils increased soil water recharge for up to three years following the deep tillage operation. Increased soil-water recharge in the para-plowed plots was found only in the first year. Crop emergence on some of the Solonetzic soils was decreased in the first year on the deep ripped plots due to poor seedbed conditions. Deep ripping increased crop production on Solonetzic soils by up to 4 years, and on Solonetzic/Chemozemic soils by up to 3 years, but had no effect on crop production on Chemozemic soils. Para-plowing also increased crop production on both the Solonetzic soils and on the Solonetzic/Chemozemic intergrades; however the effect was much less dramatic than that of deep ripping and lasted only up to 2 years. The increased crop production was the result of greater spring soil NO3-N levels and greater crop water-use efficiency. Deep ripping and para-plowing reduced soil sodicity and salinity under irrigated conditions, but not under dry-land conditions
