A field experiment was conducted during rabi season of 2017-2018 on a mixed black calcareous soil (Typic Ustropept - Periyanackenpalayam soil series) at Eastern Block, Tamil Nadu Agricultural University, Coimbatore to refine the existing fertilizer prescription equations under Integrated Plant Nutrition System (IPNS) for hybrids to suit pearl millet variety. The experiment comprised of eleven treatments with three replications in Randomized Block Design. The experimental results revealed that there was a progressive increase in response from lower target to higher targets and the magnitude of response was higher under STCR-IPNS than under STCR-NPK alone treatments. Using the experimental data, the basic parameters viz., nutrient requirement (NR), per cent contribution of nutrients from soil (Cs), fertilizers (Cf) and FYM (Cfym) towards total N,P and K uptake by pearl millet (var. CO 10) were computed based on targeted yield model. It was found that pearl millet variety requires 2.81, 1.33 and 2.53 kg of N, P2O5 and K2O, respectively to produce one quintal of grain. The contribution of nutrients from soil, fertilizers and FYM for N was 26.36, 45.44 and 27.55 per cent; for P2O5 it was 38.51, 44.14 and 16.04 per cent and for K2O it was 10.33, 87.45 and 40.15 per cent respectively. Making use of the refined basic parameters, Fertilizer Prescription Equations (FPEs) were developed under NPK alone and IPNS for pearl millet variety. Ready reckoner of fertilizer doses (nomograms) were formulated for a range of soil test values and for desired yield target viz., 3.0, 3.5 and 4.0 t ha-1. For an average soil test value of 180:24:460 kg ha-1 and yield target of 4.0 t ha-1, 105, 51 and 25 kg of fertilizer N, P2O5 and K2O is to be appiled along with FYM @ 12.5 t ha-1. The extent of saving of inorganic fertilizers for pearl millet with the application of FYM @ 12.5 t ha-1 (with 21 % moisture, 0.64, 0.27 and 0.46 % N, P and K respectively) was 38, 22 and 25 kg of fertilizer N, P2O5 and K2O respectively.
Key words : STCR-IPNS, Pearl millet, Fertilizer prescription equations.