Mechanical Soil Resistance Influenced by Different Tillage Systems and Tractor Tire Pressures

Intensive agricultural practices affect soil compaction, and their indirect and direct effects on crop growth and development are an increasingly important focus of scientific research. The objective of this study was to determine the influence of different tillage systems on soil compaction and to observe the influence of tractor tire pressure on penetrometer resistance during sowing. The three-year study was conducted on the heavy pseudogley soil of Brod-Posavina County in the Republic of Croatia. During the research, crops were observed in the following cropping sequence: soybean ( Glycine max L.) in the first year, maize ( Zea mays L.) in the second year and winter wheat ( Triticum aestivum L.) in the third year. The tillage systems as the main study factor were conventional tillage (CT) plowing to a depth of 35 cm, disc tillage (DH) to a depth of 15 cm, loosening (CH) to a depth of 30 cm, and undermining (SS) to a depth of 50 cm. The following pressures were used as a subfactor of this study, namely the pressure of the front and rear tires of the tractor during sowing: p 1 (front 1.0 bar/rear 0.8 bar), p 2 (front 2.0 bar/rear 1.6 bar), and p 3 (front 3.0 bar/rear 2.4 bar). The tillage systems applied resulted in different soil compaction, thus the deepest tillage SS had the lowest resistance and the DH tillage had the highest resistance in all three experimental years. Penetrometer measurements showed the influence of tire pressure p 1 on reducing compaction as early as the first year in 2017, while in the last year of research in 2019, tractor tire pressure p 3 during sowing contributed to a significant increase in soil compaction.