Development and Validation of Soil Test Crop Response STCR and STCR Integrated Plant Nutrition System IPNS Equations for maize Zea mays L in Vertisols of Northern Karnataka

Abstract

Field experiment was conducted during 2020-21 and 2021-22 in vertisols of newlineKarnataka at MARS, Dharwad and IWMRC, Belavatgi by adopting the inductive cum newlinetargeted yield model to develop soil test based fertilizer prescriptions under integrated newlineplant nutrition system (STCR-NPK alone and STCR-IPNS) for achieving desired yield newlinetargets of maize. There were three phases of the field experimentation. Gradient newlineexperiment (Phase I) was conducted during summer by growing fodder maize to create newlinegradient in soil fertility. In second phase, test crop maize (var. NK-6420) was grown by newlinedividing each strip into 24 plots having 21 fertilizer treated and 3 controlled plots and newlineby choosing selected combinations of four levels of N, P and K and three levels of FYM newlineat different fertility levels of maize was studied to develop STCR and STCR-IPNS newlinefertilizer prescription equations for computing nutrient doses for target yield of maize. newlineWhile the third phase of the experiment was conducted during kharif 2021-22 at newlineDharwad (Assured rainfall zone) and Belavatgi (Irrigated command area) to test the newlinevalidity of STCR and STCR-IPNS equations developed during the test crop experiment newlinein comparision with Jabalpur STCR equation with target yields of 60, 80 and 100 q ha-1. newlineThe STCR treatments were compared with RDF + FYM at 10 t ha-1 and Absolute newlinecontrol. newlineMaize green fodder yield increased with increasing fertilizer levels (20.70, 33.48 newlineand 42.33 t ha-1 with application of 0, 100 and 200 % RDF respectively) clearly newlinedemonstrated that the three fertility strips differed significantly from each other and newlinereinforced the variation in soil fertility between the three strips in the experimental field. newlineThe basic parameters viz, nutrient requirement (NR), contribution of nutrients from soil newline(Cs), fertilizers (Cf) and FYM (Cfym) were computed using test crop data. Nutrient newlinerequirement to produce one quintal of maize grain was 2.89 kg nitrogen, 0.77 kg phosphorus and 1.92 kg potassium. The per cent contribution of N, P and K was 22.08, newline50.10 and 14.27 from soi