Investigating the Impacts of Tillage and Cover Crop Management on Soil Compaction in Long‐Term Agricultural Production Sites Using a Home‐Built Dynamic Penetrometer
Gunther Liebhard, Stefan Strohmeier, Christine Stumpp, Andreas Klik, Reinhard Nolz, Hadera Kahesay Abraha, Csilla Hudek, Xiaoping Zhang, Yangyang Li, Weinan Sun, Laura Zavattaro, Octavian P. Chiriac, Marcella Biddoccu, Zsofia Bakacsi, Bela Pirkó, Gema Guzmán, José Alfonso Gómez, Tomáš Dostál, David Zumr, Martin Banov, Ekatherina Tzvetanova, Dimitre Nikolov, Marton Toth, Peter StraussABSTRACT
Agricultural management produces soil compaction depending on intensity of use, specific management and soil properties. We used an adapted, home‐built dynamic penetrometer to evaluate 20 long‐term sites of arable land, tree orchards, vineyards and grassland in Europe and China, each with different tillage and cover crop strategies. To ensure comparable results across all sites, we pre‐tested different penetrometer settings in the laboratory to cover all local conditions and provided Standard Operating Procedures. The laboratory tests showed that different settings in terms of falling hammer height and cone angle produced replicable results, and that narrow plough pans (3 cm) could be detected, even though their density was underestimated by 50%. The pre‐tests also demonstrated the dependence of the measurements on soil water content and texture, even under preset conditions close to field capacity. Consequently, the effects of different management practices were only compared directly for each site individually. The field study showed that tillage had a greater effect on penetration resistance than different cover crop systems and intensity. The majority of the more intensively tilled fields showed penetration resistance that was up to 3 MPa lower, at least partially, up to the ploughing depth compared to less intensively tilled fields. However, in only 27% of the fields, the no‐till or reduced‐till management led to an SPR greater than 2.5 MPa, indicating harmful compaction, compared to conventional management. The effects of cover crops on soil compaction were unclear with differences observed between different mixtures at only one site. Nevertheless, unlike bare soil, cover crops increased penetration resistance in the tillage horizon and reduced infiltration capacity in 75% of the fields investigated. Trends depending on management practices varied due to local soil properties. We therefore recommend farmers to include penetrometer measurements in their routine to recognize soil compaction in time and apply tailored mitigation strategies.