Main content area

Media evaluated for extended sweetpotato transplant production in heated beds

Dangler, J.M.
Journal of plant nutrition 1993 v.16 no.10 pp. 1931-1941
Ipomoea batatas, sawdust, Pinus, sand, dry matter accumulation, length, mortality, raised beds, heat treatment, planting
'Georgia Jet' sweetpotato [Ipomoea batatas (L.) Lam] transplants were produced in heated beds to compare aged pine sawdust or builders' sand (traditional media) to fresh pine bark and aged pine bark, or fresh pine sawdust (alternative media), with regard to transplant production and quality over an extended harvest period. At the first harvest, highest transplant numbers (mean 1400 transplants/m2) Were obtained with fresh pine sawdust or fresh pine bark. Media effects on transplant numbers at the first harvest agree with the results of an earlier experiment. The greater productivity of fresh pine bark compared to aged pine media and builders' sand at the early-harvest (two harvests) in the previous experiment was not confirmed in this experiment. Extended-harvest (four harvests) transplant production was greater with fresh pine sawdust (2030 transplants/m2) than with aged pine sawdust (1380 transplants/m2), but was not greater than the number of transplants produced with the other media. Transplant production averaged over the five media, decreased from 1060 and 360 transplants/m2 at the first and second harvests, respectively, to 130 transplants/m2 at each of the last two harvests. Differences in mean transplant weights due to media were found only at the third harvest. At the first harvest, greater mean lengths of transplants gown with the fresh pine media (mean 25.7 cm) than with the aged pine media (mean 21.4 cm). Shortest transplants were produced with builders' sand at the first harvest (17.8 cm) and throughout the extended season (17.5 cm). Similar effects of media on mean transplant length were observed at the early- and extended-harvest periods. Media had no effect on the percentage of intact roots at the end of the 15-week season (mean 71%).