Effect of Preceding Crops, Soil Packing and Tillage System on Soil Compaction, Organic Carbon Content and Maize Yield

Crop rotation and simplified tillage affect soil properties and consequently crop yields. The use of heavy machinery in the tillage can affect soil degradation and reduce soil productivity. The aim of this study was to investigate the effect of soil packing and different soil tillage methods applied before the sowing of maize cultivated after grassland and in monoculture on soil compaction, soil organic carbon content, and maize yield. A strip–split–plot experiment was conducted on-farm in northeastern Poland from 2017 to 2021. The soil compaction was measured in the soil layers: 0–10, 10–20 and 20–30 cm in the leaf development stage (BBCH 19), the flowering stage (BBCH 67) and the maize kernel development stage (BBCH 79). The experimental factors were as follows: 1. preceding crop—grassland, maize; 2. degree of soil packing—without soil packing, soil packing after harvesting the preceding crop; 3. different soil tillage—conventional plough tillage method, reduced tillage method. Maize cultivation following a multi-species grassland resulted in a modest 1.47% increase in soil organic carbon content compared to continuous maize monoculture. In monoculture maize, all investigated reduced tillage methods led to increased soil compaction by 0.61–0.67 MPa. However, this adverse effect was mitigated by prior grassland cultivation. Maize grown after a multi-species grassland exhibited 14% higher silage mass yields. Considering the reduction in soil compaction and the enhanced yield potential, this preceding crop is recommended for maize cultivation. Although soil packing did not significantly impact maize yields, reduced tillage methods, such as subsoiling at 40 cm, medium ploughing at 20 cm, and passive tillage, led to a significant reduction in silage mass compared to other treatments.