Influences of soil tillage and fertilization on maize yield and weed infestation
The field experiment was conducted after wheat harvesting (July 1997) on Zemun Polje chernozem. Maize was grown under dry farming system (without irrigation) for three growing seasons (the factor A: 1998, 1999 and 2000). Soil tillage systems (the factor B) included three treatments as follows: B1) zero tillage (direct sowing in non-cultivated soil), B2) minimum tillage (tillage with a soil miller only and sowing) and B3) conventional tillage (stubble field shallow ploughing, ploughing in autumn, presowing soil preparing and sowing). In each soil tillage treatment three levels of fertilization were used as follows: Cl) unfertilized (control), C2) the first level of fertilization (kg ha−1: 150 N + 105 P2O5 + 75 K2O) and C3) the second level of fertilization (kg ha−1: 300 N + 211 P2O5 + 150 K2O). The field experiment was conducted in four replicates. Area of base plot was 25 m2. Under drought stress of the 2000 growing season it was only 6.08 t ha−1 or 35% lower compared to 1999. The conventional tillage (yield 9.86 t ha−1) resulted by 24% and 84% yield increases compared to reduced tillage and zero-tillage, respectively. Using the second rate of fertilizer (yield 8.86 t ha−1) increased yields by 17% and 32% compared to the first rate and non-fertilized treatments, respectively. Weeds infestations (weeds m−2) under conventional tillage was considerably lower (7) compared to reduced (39) and zero-tillage (46).