D Kalaivanan, K Sudhir and S C Kotur
Effect of different levels and placement of 32P labelled single super phosphate on absorption of phosphorus by banana cv. Robusta under high density planting
Absorption of applied 32P by the treated as well as neighbouring banana cv. Robusta plants under high density planting was studied on a sandy clay loam soil using 32P labelled super phosphate with application of three levels of P fertilizers viz., 60, 80, and 100 per cent at 15-35, 35-55 and 55-75 cm distance from pseudostem of the plant. The first, 2nd and 3rd dose of urea, labelled single superphosphate and muriate of potash was applied to banana at early vegetative (8th leaf/65 DAP), late vegetative (16th leaf/115 DAP) and bud differentiation stages (165 DAP). Higher 32P absorption (dpm/g of dry matter) in leaf was observed in the treatments supplied 100 per cent of recommended dose of fertilizers at closer distance of 15 to 35 cm distance from pseudostem during first split application and at middle distance of 35 to 55 cm from pseudostem during second and third split application. The maximum per cent phosphorus derived from fertilizer (% Pdff) was also recorded with the application of 100 per cent recommended dose of P fertilizers in the middle distance of 35-55 cm from the pseudostem of the experimental plant. No significant difference was observed in the leaves of Robusta banana. The study has brought out the differential nature of the absorption pattern in treated plant and border plants with different levels and placement of fertilizers. Radiophosphorus applied to the root zone was absorbed by the treate plant and the neighbouring plants .