EFFECT OF NITROGEN AND PHOSPHORUS ON THE GROWTH AND YIELD OF STEM AMARANTH (Amaranthus viridus)

Abstract

A field experiment was conducted in the experimental field and Horticulture laboratory of Sher-e Bangla Agricultural University, Dhaka, Bangladesh during the period from March 2006 to July 2006 to study the effect of different levels of nitrogen and phosphorous on the growth and yield of stem amaranth. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. The experiment considered of two factors. Factor A: 4 Levels of Nitrogen (N) i.e. No (no Nitrogen /Control), N1 (92 kg N/ha), N2 (96.6 kg N/ba) and N3 (101.2 kg N/ha) ; Factor B: 4 Levels of Phosphorus (P205) i.e. Po (no Phosphorus/Control), P1 (48 kg/ha), P2 (52.8 kg/ha), P3 (57.6 kg/ha). There were altogether 16 (4x4) treatment combinations. A significant variation was observed in respect of all characters at different days after sowing (DAS) in relation with different levels of nitrogen and phosphorous application. The maximum yield and yield contributing characters were observed from N3 and the minimum was found from control treatment at all DAS. The maximum plant height (88.82 cm) was recorded at harvest (55 DAS) from N3 while the minimum (76.01 cm) was found from control. The maximum (23.76 mm) stem diameter and green yield (76.47 t/ha) was obtained from N3 at harvest (55 DAS). Significant variation was also observed in different days after sowing with the application of phosphorus. The maximum (85.40 cm) plant height, stem diameter (22.22 mm) and green yield (67.99 t/ha) recorded from where the plants received 57.6 kg P20s/ha and minimum was performed in control at harvest (55 DAS). The maximum (83.32 tlha) yield was found from the combination ofN3P3 and the minimum (34.86 t/ha) was recorded from control (N0P0). Jn the combination of different doses of Nitrogen and phosphorous the highest benefit cost ratio (1.92) was attained from the treatment combination of N3P3 and lowest befit cost ratio (0.31) was obtained from NoPo (control).