In conventional tillage system the soils under native sod are revolved for lime incorporation and crop production. The objective of this study was to evaluate the effects of surface and subsurface liming in soil under native sod. The experiment was conducted at the experimental field of the Soil Science Department, at the Federal University of Santa Maria, RS, Brazil, on a Argissolo Acinzentado Distrófico plíntico soil, médium texture, with high potential acidity (Plinthaquult), under native sod. Lime rates o/O, 2, 5.5 and 17 Mg ha' were used. On half of the plots the lime was mixed with the topsoil by disk plow. Lime was left on the surface on the other half of the plot. The crops used were com (94/95 and 96/97), ryegrass (95, 96 and 97) and soybean (95/96 and 97/98). The yield of the plants were considered high on acid soils under native sod. Plowing on the acid soil without application of lime decreased yield culture. Com and soybean yields for the two lowest liming rates were higher with surface applied lime. Subsurface applied lime, however was beneficiai for ryegrass.
acidity; channel plain; organic matter
