We evaluated the performance of several sweetpotato (Ipomoea batatas) cultivars grown on raised beds covered with biodegradable black mulch in New Hampshire. Six cultivars were evaluated over 4 years, and an additional four cultivars were evaluated in 2 or 3 years. Cultivars showed significant differences in marketable yield, percent cull, and percent small roots. The cultivars Covington and B94-14 Beauregard consistently produced high yields, whereas Vardaman consistently produced the lowest yields. ‘Georgia Jet’ exhibited variable performance, with marketable yields among the highest in 1 year and the lowest in another, largely because of a high percentage of cull roots due to severe cracking. Yields measured in our study compare favorably with average U.S. yields, with several cultivars producing over 400 50-lb bushels/acre in all years in which they were grown. In a 2-year study with the cultivar Beauregard, biodegradable mulch increased overall yields (marketable, cull, and small roots) as compared with bare ground production on raised beds. However, the percentage of culled roots was higher in mulch treatments, primarily due to breakage during digging, and the observed increases in marketable yields were not statistically significant.
