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Abstract
A study was conducted in split-plot design to determine the effect of
single- and double-row plantings on the yield of four sweet potato cultivars (local
names: 'Manager's Pudding', 'Caroline Lee', 'CBS 49' and 'CBS 32') commonly planted
on the estates of the Barbados Agricultural Management Company Ltd. Cuttings were
established on raised beds 5.5 ft apart. Single-rows consisted of cuttings placed on the
centre of the beds with a spacing of 1 ft intra-row. For the double-rows, cuttings were
established on both sides of the bed with 1.5 ft between rows and 1 ft intra-row. Shortly
after establishment, the sweet potato was sprayed with Fusilade® (Fluazifop-p-butyl)
using the recommended rate for the control of grass weeds. Mono-ammonium
Phosphate was manually placed 6 inches away from all cuttings, after they were well
established, at a rate of 100 lb per acre. Yield data showed that double-row planting of
'Caroline Lee', 'CBS 49', 'Manager's Pudding' and 'CBS 32' resulted in 21.3%, 31.4%,
16.7% and 16.8% significant decrease in average weight/ tuber, respectively, compared
to single-row plantings. The total weight of tubers/ hole also decreased from single- to
double-row planting ('Caroline Lee' - 35.7%, 'CBS 49' - 44.7%, 'Manager's Pudding' -
38.5% and 'CBS 32' - 43.5%) due to increased competition for resources in the smaller
inter-row space. Smaller tubers were obtained from double-rows. These are suitable for
the average household purchaser while the larger tubers from the single-rows are ideal
for processors. Data extrapolation showed that the total yield/ acre increased from
single- to double-row planting for each cultivar. As one moves from single- to doublerow
planting, the total number of holes per acre doubles resulting in the expected
increase in total yield. Total yield per acre (kg) increased by 28.7% for 'Caroline Lee';
10.5% for 'CBS 49'; 23% for 'Manager's Pudding'; and 13.0% for the 'CBS 32' cultivar.