Abstract:
Varieties differ in acquiring P from soil as well as in utilizing the absorbed P for grain production and this nature of crop varieties may be exploited to improve the efficiency of P fertilizers. Five wheat varieties viz. Punjab-96, Shahkar-95, Pervaz-94, Inqelab-9l and Pasban-90 were grown in the field and phosphorus was applied @ 0 or 44 kg ha'' from three inorganic sources: NP (23:23), DAP (18:46) and SSP (16% PiO>) and one industrial bye-product, DCP (42% PiOs). The method of application employed was fertigation at first irrigation when the first basal dose of N was applied as urea. Additional urea-N was top-dressed at second irrigation to maintain N rate at 150 kg ha'1 in all plots. Yield and P uptake data showed that among the varieties mean highest grain
yield was produced by Punjab-96 (5510 kg ha') and the lowest by Pasban-90 (4170 kg ha:') while lnqelab-91, Shahkar-95 and Pervaz-94 produced equivalent yield and remained intermediate- lnqelab-91 and Punjab-96 accumulated equivalent but significantly higher amount of P compared to Pasban-90. Despite equivalent P uptake, Punjab-96 was superior to lnqelab-91 in utilizing the absorbed P for grain production. Among the sources, nitrophos (NP) appeared better followed by single superphosphate (SSP), di-ammonium phosphate (DAP) and di-calcium phosphate (DCP). Thus DCP, an industrial bye-product proved comparatively less effective when applied by fertigation while the three inorganic sources were equally effective for wheat production.
