Department of Agronomy, Faculty of Crop Production Sciences, Khyber Pakhtunkhwa Agricultural University, Peshawar-PAKISTAN.
Phosphorus (P) is the second most important crop nutrient after nitrogen that increases productivity and profitability of maize (Zea mays L.) on P deficient soils in Northwest Pakistan. The objective of this study was to find the best level and time of P application for higher maize (cv. Azam) productivity and profitability. Field experiment was conducted at the Research Farm of Khyber Pakhtunkhwa Agricultural University, Peshawar during summer 2005, comprising of six P application timings [40, 30, 20 and 10 days before sowing (DBS), at sowing and 15 days after sowing (DAS)] as main plots, and three P levels (30, 60 and 90 kg P ha-1) as subplots. The highest level of P enhanced phenological development, and increased ear length, number of rows and grains ear-1, grain weight, economic yield, shelling percentage, and net returns. Application of P at 10 DBS had marked increase in ear length, grain weight, grain yield, shelling percentage and net returns; while plots that received P at sowing time produced the highest number of rows and grains ear-1. There was no much difference in the net returns when P was applied at 10 DBS (22, 560 PKR ha-1) or at sowing (21, 883 PKR ha-1). It could be concluded from the study that application of 90 kg P ha-1 either at 10 DBS or at sowing time is necessary for profitable maize production in the study area.