Main Article Content
To study the effect of plant derived Humic acid (HA) on the nutrient use efficiency and yield of onion a pot experiment was conducted in a greenhouse of Land Resources Research Institute, National Agricultural Research Centre Islamabad, during year 2013. The experiment was laid out in Complete randomized design with two factor i.e. HA (150 mL 5 kg-1 and 300 mL 5 kg-1) and Phosphorus (P) levels (60 kg ha-1 P2O5 (75 %) and 80 kg ha-1 P2O5 (100 %). Soil application of plant derived HA @ 300 mL 5 kg-1 along with 80 kg ha-1 P2O5 as Di-ammonium Phosphate (DAP) recorded the highest onion yield of 13.47 t ha-1. However it was statistically at par with the treatment receiving 75% (60 kg ha-1) P application along with plant derived HA @ 150 mL 5 kg-1 soil. Secondly soil application of plant derived HA @ 300 mL 5 kg-1 along with 80 kg ha-1 P2O5 showed highest content of P (0.22%) in onion plant at maturity whereby HA @ 150 mL 5 kg-1 along with 60 kg ha-1 P2O5 (75% RDF) registered highest content of N (4.1%). It may concluded from the result of the experiments that HA applied @ 300 mL 5 kg-1 integrated with Phosphatic fertilizers gave promising result and may be recommended for enhancing the onion yield and P and N concentration of soil.
Keywords: Humic acid; Onion; Phosphorus; Nutrient concentrations; Yield