EFFECT OF PHOSPHORIC ACID AND POTASSIUM HUMATE ON GROWTH AND YIELD OF MAIZE IN SALINE-SODIC SOIL

Abstract

Phosphorus (P) is the 2nd most deficient nutrient among plants (<10 mg P kg−1 soil) in >90% soil of Pakistan. The crop requirement is achieved by fertilization however effectiveness of the current P (Phosphorus) containing fertilizers applied as broadcast is less (20%). Application of phosphoric acid (PA) and potassium humate (PH) not only increases the nutrients availability to plant but also improves soil characteristics. A pot experiment was carried out to evaluate the behavior of PA and PH in saline-sodic soil for nutrient availability in maize. Twenty-seven plastic pots were used in this experiment. PA was applied according to recommended dose of Punjab Agriculture Department (NPK 200-150-200 kg ha-1 ), while the PH was applied according to the Agrolix fertilizer private limited recommendation (50 and 100 kg ha-1 ). The plant growth parameters (length and dry weight of root and shoot), ionic interaction (N, P, K, Fe, Zn, Cu and Mn in root, shoot and grain) and grain weight were recorded. The results showed 241% and 315% more shoot and root dry weight as compared to control with combined application of PA and PH. The length of shoot and root were improved to 181% and 232% as compared to control. The grain yield was positively correlated with shoot dry weight (r2 = 0.6618). Application of PA decreased the soil electrical conductivity (EC) and sodium adsorption ratio (SAR) about 91% and 96% respectively after one cropping season. Grain yield had highly significant (r2= 0.829) negative correlation with soil ECe (Electrical conductivity) whereas it was also negatively correlated with soil SAR (r2=0.5942). Results further explained the significant positive correlation between phosphorus and iron concentration in grain (r2 = 0.7454). However, phosphorus concentration was not correlated with grain zinc concentration (r2 = 0.1798).