Tillage and nitrogen effects on winter wheat yield and selected soil physical properties on hypogley of Eastern Croatia

Abstract

The field research was conducted on hypogley in Vrbanja, Croatia, during four growing seasons from 1992/1993 to 1995/1996. They included five soil tillage systems and three nitrogen fertilization levels in four replications for winter wheat (Trilicum aestivum L.) after soybeans (Glycine max L.) as a preceding crop. Tillage treatments were: PL=conventional tillage (ploughing to 20 cm depth, diskharrowing and standard sowing); DS=diskharrowing and standard sowing; MC=tillage by multitiller and chisel, standard sowing; RS=soil tillage and sowing by RAU-Rotosem; PR=ploughing to the depth of 20 cm + RS. Nitrogen fertilization treatments were 140 (N1), 170 (N2) and 200 kg N ha(-1) (N3). Wheat grain yields effects by tillage were as follows: 6.00 (PL), 5.79 (DS), 5.65 (MC), 5.61 (RS) and 5.90 t ha(-1) (PR). Significant differences of yields were found only in the first year of testing. Nitrogen fertilization resulted by non-significant differences of yields as follows: 5.56 t ha(-1) (N1), 5.85 t ha(-1) (N2) and 5.96 t ha(-1) (N3). The conclusion is that under certain environmental conditions it is possible to apply reduced soil tillage and moderate N fertilization.