Changes in biochemical constituents and antioxidant enzyme activity in groundnut (Arachis hypogaea L.) by the addition of coated multi-nutrient fertilization in calcareous soil

Sulphur and micronutrients play a vital in the growth and development of plants due to their catalytic effect on many metabolic processes. A field experiment was conducted to explore the changes in various biochemical constituents and antioxidants enzyme activities in response to coated multi-nutrient fertilization. The experiment consisted of five organic acids (citric acid, humic acid, fulvic acid, salicylic acid) and amino acid (glycine) coated multi-nutrient fertilizer sources applied at five different levels (0, 5, 10, 12.5 and 15 kg ha-1). Groundnut leaf samples were collected and analyzed for biochemical constituents such as proline, soluble protein and antioxidant enzymes viz., superoxide dismutase, catalase, peroxidase and carbonic anhydrase activities at harvest stages. The results revealed that, application of fulvic acid coated multi-nutrient fertilizer at 15 kg ha-1 registered lesser proline (5.93 µmoles g-1) and higher soluble protein (22.2 mg g-1) content, superoxide dismutase (8.93 EU mg-1), catalase (18.2 µg H2O2 min-1 g˗1), peroxidase (6.11 µg min-1 mg˗1) and carbonic anhydrase (14.8 EU mg-1) activities at harvest stage followed by 12.5 kg humic acid coated multi-nutrient fertilizer. The lesser response was noted with NPK control in influencing the biochemical constituents and antioxidant enzymes. It was concluded that fulvic coated multi-nutrient fertilizer at 15 kg ha-1 was the better source for improving the biochemical constituents and antioxidant enzymes of groundnut in calcareous soils.