Influence of conservation tillage and crop rotation on the resilience of an intensive long-term potato cropping system: Restoration of soil biological properties after the potato phase

Conservation tillage in potato (Solanum tuberosum L.) systems, in cool-humid climatic regions, can benefit soil physical and biological properties. However, insight is needed on how the combination of conservation tillage and crop rotation enhances the resilience of intensive short-term potato cropping systems, specifically the restoration of the soil condition after the perturbations that occur in the potato phase. A long-term 3-year rotation (potato-barley-red clover) and conservation tillage study was initiated in 1994 on a fine sandy loam in Prince Edward Island, eastern Canada. Over a 3-year period (2004–2006), soil physical (bulk density) and biological (C and N fractions, structural stability; densities of plant parasitic and bacterial-feeding nematodes, and micro-arthropod abundance and diversity) properties were monitored over each phase of the crop rotation cycle to assess the restoration or rejuvenation of the surface (0–10 cm) soil condition. Conservation compared to conventional tillage, increased soil organic C, large water-stable macro-aggregates, and soil particulate C and N in the potato year only. After the potato phase, rotation crops were associated with the further restoration of all soil C and N fractions and soil structural stability indices; and also increases in soil microbial biomass C and microbial activity indices, and soil Collembola abundance. Soil nematode densities showed some incidences of treatment differences but no clear trends. The study indicated that conservation tillage has a positive influence on soil biological properties and that the 3-year rotation successfully restored many of the soil parameters that had declined in the potato year.