Yield Potential of Fourteen Organic Sweetpotato Cultivars Grown in Various Mulches

A field experiment was conducted on fourteen cultivars of organic sweetpotato at the Tennessee State University Organic farm in summer 2015 growing season. Cultivars ‘Beauregard’, `Porto Rico’, `O henry’, `All purple’, `Carolina ruby’, `Ginseng’, `Murasaki’, `Covington’, `Centennial’, `Japanese purple’, `Burgundy’, `Hernandez’, `Old yellow’ and `Orleans’ were grown in raised beds in three mulch treatments black plastic, wheat straw, pine needle and no mulch (control) using a complete randomized block design with four replications. Experimental plots were drip-irrigated and maintained in organic management system as per standards of National Organic Program.  Two applications of organic fertilizer were applied during the crop cycle and data collected on the yield, length, weight and diameter of the roots. The total, marketable and cull yields varied significantly (p<0.05) among the cultivars, however there was no significant difference in yield between the mulch treatments tested. The total yield was highest in ‘Carolina ruby’ (34,790 lb/acre) and the least culls observed in ‘All purple’ cultivar. In the group consisting of ‘Ginseng’, ‘Carolina ruby’, ‘Old yellow’ and ‘Hernandez’ varieties, the highest mean weight of roots grown was measured in the wheat straw mulch bed (15.60 oz), which was significantly higher than the plastic mulch with least root weight (11.19 oz). In the group consisting of `Orleans’, `Murasaki’, `Covington’, `Japanese purple’, `Burgundy’ and `Centennial’ the heaviest root and longest length was recorded in the plastic mulch (18.92 oz and 6.9 cm) and the least root weights and length was in the pine needle mulch (15.27 oz and 5.66 cm).  These preliminary findings suggests that mulches can influence the weight, length and diameter of independent sweetpotato roots.