Enzymatic and Nutritive Evaluation of Zinc and Organic Fertilization on Field Maize Yields in Islamabad - Pakistan

Low fertility and organic matter contents in soil limit the nutrient bio-availability for crops, potentially leading to poor nutrition in the animals and human beings that consume those crops. This field study on maize production employed integration of organic and chemical fertilizers to determine their impact on plant enzymatic activities in relation to crop production, and nutrient dynamics in plants and soil. The treatments compared were: control (no application of N from any source); 100% N from fertilizer (FN); 75% FN + 25% N from organic manure (ON); and 50% FN + 50% ON. Further, all these treatments were superimposed by three levels of zinc (Zn) fertilizer, viz., 0, 4, 8 kg Zn ha-1.Conjunctive use of FN and ON with the ratio of 75+25 along with Zn application at the rate of 4 kg ha-1rendered the highest maize grain yield as compared to sole N application from chemical fertilizer. Similarly, enzymatic activities of nitrate reductase (NR) and superoxide dismutase (SOD) were significantly affected with combined use of N and Zn. Nitrogen, phosphorus and zinc contents in diagnostic leaves of maize were also higher in organically substituted treatments.