Long-term conservation tillage in potato rotations in Atlantic Canada: Potato productivity, tuber quality and nutrient content

Carter, M. R., Sanderson, J. B. and Peters, R. D. 2009. Long-term conservation tillage in potato rotations in Atlantic Canada: Potato productivity, tuber quality and nutrient content. Can. J. Plant Sci. 89: 273-280. Conservation tillage in combination with mulches in potato (Solanum tuberosum L.) farming systems can maintain crop productivity and improve soil properties, in comparison with conventional tillage systems. However, information is needed on the long-term influence Of Such practices on potato crop parameters. A study was initiated in 1994 on a Charlottetown fine sandy loam (Orthic Podzol) in Prince Edward Island to assess the feasibility of using conservation tillage practices in combination with crop residue Mulches (after the potato harvest) on potato production in two different potato rotations: a 2-yr barley-potato rotation and a clover-based 3-yr (barley-red clover -potato) rotation. In the conservation tillage system, the primary tillage event was moved from the autumn to spring and the degree and depth of tillage were reduced by replacing the conventional mouldboard plough (20 cm depth) with a shallow (15 cm depth) one-pass chisel plough just prior to potato planting. Potato yield and tuber quality, surface residue levels after potato planting, and tuber mineral content were evaluated from 2000 to 2007. Adoption of conservation tillage over the long-term did not adversely influence total or marketable potato yield, or tuber quality. The clover-based 3-yr rotation, compared with the 2-yr rotation had little effect on total potato yield (42 vs. 44 Mg ha(-1)), but produced significantly higher marketable tuber yields (38 vs. 32 Mg ha(-1)), for four of the eight yrs of the study. The conservation tillage system, for both rotations, provided relatively high Surface residue levels (>30%) after potato planting, compared with the bare soil surface in the conventional tillage system. Nutrient and trace element contents in tuber dry matter were similar between conservation and conventional tillage. Tuber uptake of nitrogen and other nutrients were slightly greater under the 3-yr, compared with the 2-yr rotation, and associated with tuber dry-matter yield differences. The results of the 14-yr study confirm the conclusions of previous short-term studies that a reduction in depth and intensity of tillage for potato culture is yield neutral, and a viable alternative to conventional tillage systems for potato production on sandy loams in eastern Canada.