The potential for adverse effects on soil quality and erosion in pinto bean-potato rotations is significant due to low levels of residue input to the soil following potatoes or beans, and the effect of tillage on soil structure, particularly in sandy-textured soils typical of the potato-growing area of Manitoba. Soil quality is reduced by low inputs of residue and carbon commensurate with an increase in the proportion of small and unstable aggregates susceptible to erosion. Furthermore N and P concentrations at the soil surface may be affected by various management options including fall cover crops, application of straw and the use of composted manure. In a study conducted at Carberry, MB, from 2000 to 2006, KCI-extractible NO(3)-N and Olsen P were determined in the fall prior to seeding in each year of the study. Water-soluble P, determined in the fall of 2005 for selected treatments, increased with application of compost. Soil organic C, total N and the proportion of erodible (
