The effect of the Dyker on infiltration, soil erosion, and waterlogging on conventionally farmed potato fields in the Swiss Plateau

Tubers and root crops are a typical element of the crop rotation system widely practiced in the Swiss Plateau and especially prone to soil erosion by water, resulting in recurrent soil loss and considerable off-site damage. Improved cultivation practices are therefore needed to counteract and mitigate the erosion risk. This research evaluates the effectiveness of a device called the Dyker, which was trialled during two cropping seasons. The Dyker consists of a set of parallel wheels with three inclined shovels each. It is attached to the rear end of a potato planting machine and digs holes into the bottom of the furrows between the potato ridges. The holes are intended to improve water infiltration, and minimize surface runoff and soil erosion. A dye tracer experiment showed that in treated furrows, water infiltrates the compacted subsoil below the plough horizon, while in untreated furrows, hardly any water infiltrates deeper than 20 cm below the surface. Drone photographs showed that the Dyker effectively reduces the amount of stagnant water in depressions: while in treated furrows, rainwater was evenly retained in small holes and infiltrated the soil locally, in untreated furrows it drained to the lowest point of the plot. Due to saturation, excess water remained in the untreated furrows for several days and created anaerobic conditions in the adjacent potato ridges and ultimately led to crop failure. In addition, measurements of temporal and spatial changes of the cross-sectional geometry of furrows showed more erosion and deposition processes in untreated furrows. The positive changes in surface structure diminish in time, as the small holes between the micro-dams gradually fill up, depending on rainfall amounts and intensities.