Effect of phosphorus on growth and yield of maize (Zea mays) under arid conditions of Kandahar, Afghanistan

An experiment was conducted during summer 2015 at the research farm of the Afghanistan National Agricultural Science and Technology University, Kandahar, to assess the effect of variable levels of phosphorus on growth and productivity of maize (Zea mays L.) under semi-arid conditions of Kandahar, Afghanistan. The experiment was laid out in a randomized complete, block design with 3 replications, having a plot size of 4.25 m × 5.60 m with row-to-row distance of 0.60 m and plant-to-plant distance of 0.25 m. The levels of phosphorus were 0 (control), 15, 30, 45, 60, 75 and 90 kg P₂O₅/ha. Different levels of phosphorus significantly influenced all growth parameters of maize, viz. plant height, leaf area index, number of green leaves per plant, dry-matter accumulation, leaf area duration, crop growth rate and net assimilation rate; and yield. The application of 75 kg P₂O₅/ha resulted in the maximum plant height (200.6 cm), higher leaf area index (6.41), greater dry matter accumulation (222 g/plant), net assimilation rate (10.9 g/m²/d) and grain yield (6.51 t/ha) compared to the control. Thus, P may be applied at the rate of 75 kg P₂O₅/ha for getting higher grain yield and income in the agro-ecological conditions of Kandahar, Afghanistan.