Predicting Soil Compaction Risks Related to Field Traffic during Silage Maize Harvest

Reducing the traffic intensity and the mitigation of unnecessary traffic especially with heavy vehicles and high ground contact stress are basic requirements for preventing harmful soil compaction. This study focuses on quantifying traffic intensity and evaluating soil compaction risks during silage maize (Zea mays L.) harvest. Based on GPS data recorded by farm vehicles used on two study fields, wheel track patterns and the corresponding contact stresses have been modeled, using empirical approaches. Modeling the wheel track patterns considers the vehicle characteristics (e. g., axle width, tire type and size, and machine weight), and the changes in wheel load and contact stress during loading. The modeling results reveal that up to 62.8% of the field area had been trafficked during a single harvest. Between 16.4 and 26.8% of the field had been subjected to contact stresses exceeding 100 kPa. The actual vehicle-induced stresses calculated for the wheel track patterns were applied to model the stress distribution inside of the soil according to a method described by Horn and Fleige. The susceptibility of wheeled soil horizons to soil compaction was derived from a ratio between precompression stress and soil stress, which provides a useful measure of effective soil strength. Based on three scenarios, this article discusses how geospatial simulations might contribute to soil sustainability through an improved management of field traffic. Simulation results suggest that the risk of plastic subsoil deformation might be reduced from about 70% (related to the wheel track area) at water saturation to < 5% at a matric potential of pF 2.5.