Supplementary zinc nutrition in maize (Zea mays L.) hybrids through soil and foliar application

Maize is high nutrient demanding crop and needs balanced nutrition. Maize is also sensitive to zinc deficiency. Zinc is mostly deficient in our soils and application of zinc fertilizer is required to explore its potential. Crop species and even cultivars within a species vary in their Zn requirement. A field experiment was conducted during spring 2011 at Agronomic Research Area, Department of Agronomy, University of Agriculture, Faisalabad, Pakistan to evaluate the Zn uptake and grain enrichment in three maize hybrids (Pioneer-32 F10, Monsanto-6525 and Hycorn-8288) through the application of ZnSO4. The ZnSO4 treatments comprised; soil application at the time of sowing @ 12 kg per ha, foliar spray at vegetative stage 9 leaf stage @ 1% solution of ZnSO4 and foliar spray at reproductive stage (anthesis) @ 1% solution of ZnSO4 and one treatment was maintained as a control. All the hybrids showed the significant differences in all physiological, yield and qualitative parameters. Different ZnSO4 treatments significantly affected all the physiological and quantitative parameters of maize hybrids except plant height, stem diameter, number of grains per cob and 1000-grain weight. Maximum grain yield (8.76 t per ha) was measured in Monsanto-6525 when foliar spray of ZnSO4 was applied at 9th leaf stage. Foliar spray of ZnSO4 increased 38% and soil application gave 23.7% more grain yield than control treatment. As regard quality parameters, Pioneer-32 F10 and Hycorn-8288 accumulated more zinc contents in grains but Monsanto-6525 attained more zinc concentration in straw. Foliar application of ZnSO4 at 9 leaf stage attained 19.42% more zinc contents in grains as compare to other ZnSO4 treatments. Maximum grain zinc contents was found in Pioneer-32 F10 when ZnSO4 was sprayed at 9 leaf stage but in straw Monsanto-6525 accumulated maximum zinc contents when ZnSO4 was applied to soil. Foliar application of ZnSO4 at 9th leaf stage in Monsanto-6525 hybrid gave higher grain yield and net field benefit.