Response of Maize to Soil Applied Zinc Fertilizer under Varying Available Zinc Status of Soil

Among micronutrients, zinc is recognized as one of the main limiting factors of growth and yield of maize crop. To study the response of different levels of Zn as ZnSO4 on growth and yield of hybrid maize (NK 6240), field experiments were conducted at farmers' fields in Erode district with varying initial soil Zn status. The treatment consisted of six levels of Zn (0 1.25, 2.50, 5.00, 7.50 and 10.0 kg ha-1) replicated four times in a Randomized block design. The results revealed that the highest plant height, thousand grain weight, cob yield, stover and grain yield were recorded in the treatment with 7.50 kg Zn ha-1 in location 1 having low initial Zn status, 5.00 kg Zn ha-1 in locations 2 and 3 having medium and high initial Zn status respectively. Thus, the highest grain yields of 7.42, 7.45 and 7.56 t ha-1 were obtained with application of 7.50, and 5.00 kg Zn ha-1 in location 1 and location 2 and 3 respectively, the yield increase being 39.08, 33.15 and 28.84% over NPK control. The results of the study clearly indicate that there was a significant response to the applied Zn in soil having severe Zn deficiency, while the soil having adequate Zn status also showed comparatively better and there was a decline or no response to the applied Zn at higher levels in soil having high zinc status.