Epsilon Open Archive

Abstract

The effects of recompaction after primary tillage were studied in two types of experiments: (1) Plants grown in soil cores sampled in two field experiments, in plots with mouldboard ploughing and with shallow tillage. The cores were sampled before and after seedbed preparation, in order to obtain a large variation in bulk density. (2) Plants grown in field experiments, with and without recompaction in three primary tillage systems: mouldboard ploughing, chisel ploughing to 10 cm, chisel ploughing to 20 cm. The recompacted plots were trafficked twice track-by-track with a tractor, weight 4500 kg, inflation pressure 50 kPa. In the soil cores, no general relationship between yield and bulk density was found. However, the average yield was higher in cores sampled after seedbed preparation, indicating a positive effect of recompaction on yield. The yield difference was highest in cores from mouldboard ploughed plots. In the field experiment there was a large and statistically significant increase in yield in recompacted plots, regardless of primary tillage system. In non compacted plots, the bulk density was similar for the different tillage systems to a depth of 10 cm. In the layer 10-25 cm it was highest in the treatment which was chiseled to 10 cm. In compacted plots, there was no significant difference in bulk density between the tillage systems. The results in the field experiment indicate that the chisel plough lowers bulk density to the same degree as the mouldboard plough in the tilled layer, and that recompaction can increase yield also in shallow tillage.