Influence of crop rotation on selected chemical and physical soil properties in potato cropping systems

Crop yields are often increased through crop rotation. This study examined selected soil chemical and physical properties that may constitute the N and non-N related effects of crop rotation in potato cropping systems. Potato (Solanum tuberosum L. Norwis) was grown continuously and in two-year rotations with annual alfalfa (Medicago sativa L. Nitro), hairy vetch (Vicia villosa Roth), white lupin (Lupinus albus L. Ultra), and oat (Avena sativa Astro). Hairy vetch contributed more residue N than any other crop rotation, ranging from 110 to 119 kg N ha−1. Inorganic N concentrations in potato soils were related to the previous crop’s residue N contents, and were highest following vetch and alfalfa and lowest following oat and potato. The highest mineralizable N concentration was found following vetch (46.6 mg N kg−1). Saturated soil hydraulic conductivity in potato following all rotations ranged from 9.88 to 11.28 cm h−1 compared to 5.71 cm h−1 for continuous potato. Higher soil water contents were maintained in the 30 to 45 cm depth for all rotations compared to continuous potato. Thus several parameters indicate substantial N effects associated with particular crop rotations. Soil hydraulic conductivity and soil water status may also represent significant components of the rotation effect not directly related to N for these cropping systems.