An alternative to mitigate soil compaction and improve crop yield under no-till systems

Soil compaction has caused significant crop yield losses owing to deleterious changes in the soil physical quality in the root zone. Our objective was to evaluate the use of seed drills equipped with fixed shanks operating at two depths under different levels of soil compaction as an alternative to mitigate soil compaction and improve crop yield in no-till (NT) conditions. The study was conducted in Paraná, southern Brazil, on a Rhodic Ferralsol under 20 years of NT management. The treatments included (i) four levels of induced soil compaction (0, 3, 6, and 9 tractor passes) and (ii) two operating depths of the seed drill shank (shallow = 10 cm and deep = 15 cm) as a strategy to mitigate soil compaction. The treatment effects on soil physical quality were quantified through soil air permeability, bulk density, water and air storage capacity, and penetration resistance, measured within 0–10 cm and 10–20 cm soil depths. Plant responses to the treatments were quantified by measuring the stem diameter, shoot dry mass, leaf area, plant height, and light interception. We measured the number of pods per plant at harvest, root diameter and length, and the grain yield. Soil compaction caused by tractor traffic increases water retention and decreases air storage capacity in the soil. The deep-acting shank significantly improved soil physical conditions for root growth and development compared with the shallow shank (10 cm), reducing soil bulk density by approximately 20% and penetration resistance by nearly 50%. Improved soil physical conditions within deeper soil layers promoted greater root length in the first 20 cm of soil profile, ensuring greater crop resistance to extreme weather. Overall, using seed drills equipped with deep-acting shanks is an efficient alternative for mitigating topsoil compaction (up to 15 cm) and promoting plant development in NT systems.