Abstract

A field experiment to study the influence of fertigation of N, P and K fertilizers on physiological parameters of cocoa (Theobroma cacao L.) was conducted at the Department of Spices and Plantation Crops, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during January 2010 - December 2011. The experiment was laid out with thirteen treatments replicated three times in a randomized block design. The fertigated plants especially with water soluble fertilizers were observed to be in a better physiological state at different stages of crop growth when compared to plants fertilized in the conventional manner. Among the treatments, T4(125 per cent ‘Recommended Dose of Fertilizers’ as water soluble fertilizers (WSF) through drip irrigation) increased the physiological parameters viz., leaf area (325.4 cm2), specific leaf weight (6.48 mg cm-2), total chlorophyll content (2.01 mg g-1),nitrate reductase (1.57 μg of NO2g-1 h-1), peroxidase (0.89 D430 nm g-1h-1), C/N ratio in leaves(14.6 %) and stomatal characters like stomatal length (17.3 microns), stomatal breadth (13.9microns), stomatal size (225.8 mm2).

Keywords: Fertigation, drip, micro sprinkler, physiological parameters, water soluble fertilizers.