Inter-Row Subsoiling and Irrigation Increase Starch Potato Yield, Phosphorus Use Efficiency and Quality Parameters

Soil compaction due to the intensive use of heavy machinery is often a problem in potato production. Compaction can limit vertical root growth, water and nutrient uptake, and air and water infiltration, resulting in substantial yield reductions. This study examined the effects of inter-row subsoiling and irrigation on potato yield, tuber quality and phosphorus use efficiency (PUE) in three experiments in southern Sweden on soils with a documented plough pan at 25-30 cm. Potato (Solanum tuberosum L.) was grown in plots treated with inter-row subsoiling to a depth of 55 cm post planting, but prior to the start of root development, or in non-subsoiled plots. In addition, the interaction between inter-row subsoiling and irrigation was investigated under three different irrigation strategies: control (non-irrigated), intensive irrigation and moderate irrigation. Inter-row subsoiling significantly increased average starch yield, phosphorus use efficiency and total uptake of phosphorus in the three experiments. Irrigation significantly increased starch yield and tuber quality. Potato quality was significantly improved by a decrease in the incidence of common scab in the intensive irrigation regime, but the incidence of green tubers increased in the subsoiled plots. No significant interaction between tillage treatment and irrigation strategy was observed.