EFFECT OF PLANTING GEOMETRY, NITROGEN-PHOSPHORUS RATIO AND HAULM CUTTING ON THE PRODUCTION OF SEED POTATO

Abstract

Production of maximum number of seed-sized tubers should be the main component of seed potato (Solanum tuberosum L.) production programme in Bangladesh to improve the tuber yield. From this perspective a field experiment was carried out in the research field of Sher-e-Bangla Agricultural University (SAU), Dhaka-1207, during November, 2015 to March, 2016 to investigate the effects of planting geometry, nitrogen and phosphorus ratio and haulm cutting on the production of seed potato. “Courage” was used as planting material under present study. The experiment comprised of three different factors as treatments namely, factor A: Planting geometry: S 1 = 60 × 20 cm and S = 60 × 15 cm; factor B: Ratio of nitrogen (N): phosphorus (P): L 1 =100:40 and L 2 2 = 150:50 and factor C: Period of haulm cutting: H 1 = at 80 DAP (days after planting) and H

= at 90 DAP. The experiment was laid out in a 3 factors split-split-plot design with four replications, where the planting geometry assigned to main plots; ratio of nitrogen and phosphorus to sub-plots and periods of haulm cutting to sub-sub plots. Results demonstrated that most of the parameters were significantly influenced by planting geometry, nitrogen and phosphorus ratio and haulms cutting period. In case of growth parameters, only the combination of planting geometry and fertilizer ratio noted a significant variation. Haulm cutting period had no effect on growth parameters. In aspect of yield components, the highest weight of tuber hill 2 ii -1 (g), average tuber weight (g), tuber yield (t ha -1 ) and seed potato yield (t ha -1 ) was found under higher planting geometry, higher ratio of N: P and late haulm cutting. In case of combination, the highest weight of tuber hill -1 (455.62 g),

average tuber weight (54.54 g), tuber yield (37.96 t ha ) and seed potato yield (30.06 t ha -1 ) were exhibited from S 1 L 2 H treatment i.e., the wider planting geometry (60cm × 20cm), higher nitrogen and phosphorus (150:50 kg ha 2 ) in combination with late haulm cutting (at 90 DAP) whereas S treatment combination was the worst one. From this study, it may be concluded that the best combination of planting system from the present study may put remarkable contribution for minimizing the seed scarcity to improve the tuber yield for the betterment of farming community.