TARGETED YIELD BASED FERTILIZER PRESCRIPTION MODEL FOR SCENTED RICE
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Date
2019-07
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AAU, Jorhat
Abstract
Field experiments were conducted at the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat during the year 2017-18 and 2018-19 to generate Targeted Yield based Fertilizer Prescription Model for Scented Rice. In order to develop fertilizer prescription equations, fertility gradient experiment was conducted taking kharif rice (cv. Ranjit) as exhaust crop by creating three fertility gradient strips. After harvest of gradient crop, test crop experiment was conducted in the same field with scented rice (cv. Keteki joha) by superimposing 24 treatment combinations consisting of five levels of N (0, 10, 20, 40 and 60 kg ha-1), four levels of P2O5 (0, 5, 10 and 20 kg ha-1), three levels of K2O (0, 10 and 20 kg ha-1) and three levels of vermicompost (0, 2 and 3 t ha-1) in each of these fertility gradient strips.
Integrated nutrient management approach brought about a positive influence on organic carbon, soil available nutrient status, crop yield and uptake of nutrients by scented rice. Combined application of 60 kg N, 10 kg P2O5 and 10 kg K2O per hectare along with 3 tonnes of vermicompost per hectare resulted the highest available NPK in soil along with the highest crop yield and uptake of nitrogen, phosphorus and potassium by rice as compared to other treatments.
Fertilizer prescription equations were formulated for scented rice by following Ramamoorthy’s Inductive- cum-targeted yield approach. Based on the experiments, the nutrient requirement (NR) for producing one quintal of scented rice was found to be 2.96, 0.21and 2.67 kg q-1 with respect to N, P and K, respectively. The soil efficiency for N, P and K was found to be 36.44%, 37.13%, 50.17% in 2017-18, respectively and 35.33%, 32.88%, 49.87% in 2018-19, respectively and 35.89, 35.01, 50.02 kg q-1 in pooled analysis, respectively. The N, P, K contributions to scented rice from fertilizers were 52.22%, 23.08%, 63.55%, respectively in 2017-18 and 54.43%, 23.04%, 64.13%, respectively in 2018-19 and 53.33, 23.06, 63.84 kg q-1, respectively in pooled analysis and found highest in K-fertilizer. Conversely, the per cent contribution of N, P and K from organic component that is organic efficiency was 9.69%, 1.08%, 21.6%, respectively in 2017-18 and 10.57%, 1.15%, 22.4%, respectively in 2018-19 and 10.13, 1.12, 22 kg q-1, respectively in pooled and found to be unassuming in all the nutrients. Based on nutrient requirement, contribution from soil, contribution from fertilizer and contribution from organic manure the fertilizer prescription equations were developed for scented rice (cv. Keteki joha) and an estimate of fertilizer doses were formulated in the form of ready reckoner for a range of soil test values and desired yield targets.