Abstract

A field experiment was conducted on a Typic Ustropept (Irugur soil series) soil of Western Zone of Tamil Nadu to refine the existing fertilizer prescription equation for rainfed maize adopting the inductive-cum-targeted yield model, and fertilizer requirements were quantified for rainfed maize based on soil test and yield target. The basic parameters viz., nutrient requirement (NR) and contributions of nutrients from soil (Cs), fertilizer (Cf) and farm yard manure (Cfym) were computed from the field experimental data. Using the basic parameters, fertilizer prescription equations were developed based on integrated plant nutrition system (IPNS), and nomograms were formulated for the desired yield target of rainfed maize for the given soil test values. The extent of saving of inorganic fertilizers for rainfed maize was computed using the fertilizer prescription equations under IPNS with the application of FYM @ 12.5 t/ha (32% moisture and 0.50, 0.21 and 0.49% of N, P and K, respectively, was 22, 17 and 20 kg of fertilizer N, P2O5 and K2O, respectively, when applied along with the N, P and K fertilizers as per soil test and desired yield target. To validate the fertilizer prescription equations developed for rainfed maize under IPNS, field experiments were carried out during 2013–15 in three locations. The per cent achievement of the targeted yield of all the three verification trials was within ±10% variation proving the validity of the equations for prescribing integrated fertilizer doses for rainfed maize.