Conservation Tillage in Potato Rotations in Eastern Canada

Abstract

Potato (Solanum tuberosum L.) farming systems are often associated with soil degradation due to their excessive use of tillage and production of low levels of crop residue in the potato year. Results from a 12-year study, initiated on a fine sandy loam (Orthic Podzol) in Prince Edward Island (eastern Canada), were evaluated to assess the use of conservation tillage (CT), compared to conventional tillage, in 2 year (barley-potato) and 3-year (barley red clover potato) rotations. The CT strategy was to shift the primary tillage event for the potato phase from the autumn to spring, and to reduce the degree and depth of tillage. Mulches were used on all plots after potato harvest to provide soil cover over the cool season. Potato yield, soil cover, soil organic matter and structure, and soil-borne diseases were used as indicators to assess the feasibility of the cropping systems. Marketable potato yield was similar between the two tillage systems. The CT system provided relatively high surface residue levels after potato planting, compared to the bare soil surface in the conventional tillage system. Soil organic carbon and soil structural stability were significantly increased at the 0-10 cm soil depth in the CT, compared to the conventional system. Soil-borne diseases of potato were significantly reduced in 3 year rotations compared to 2-year rotations, but were mainly unaffected by tillage practice. Overall, use of CT in 3-year potato systems has the potential to maintain crop productivity and protect the soil resource.