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Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 08 (2018) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2018.708.129 Yield Targeting for Rice under SRI on Alfisols of Tamil Nadu through Soil Test based Integrated Plant Nutrition System S. Maragatham1*, R. Santhi2, K.M. Sellamuthu2 and Pradip Dey3 1 2 Agricultural College and Research Institute, Kudumiyanmalai, Pudukkottai, TNAU, India All India Coordinated Research Project for Soil Test Crop Response Correlation (AICRPSTCR), Department of Soil Science and Agricultural Chemistry Tamil Nadu Agricultural University, Coimbatore - 641 003, Tamil Nadu, India 3 AICRP-STCR, Indian Institute of Soil Science (IISS), Bhopal, India *Corresponding author ABSTRACT Keywords Fertiliser prescription equations, Rice, SRI, Soil test crop response, Targeted yield Article Info Accepted: 08 July 2018 Available Online: 10 August 2018 Soil Test Crop Response studies involving Integrated Plant Nutrition System (STCR IPNS) were conducted on a Typic Haplustalf of Tamil Nadu, Southern India for developing fertiliser prescriptions for desired yield targets of rice- rice sequence under System of Rice Intensification (SRI). By adopting the Inductive cum Targeted yield model, variations in soil fertility with reference to soil available nitrogen (N), phosphorus (P) and potassium (K) were established and test crop experiment was conducted with rice-rice sequence. The findings pertaining to rabi season is discussed in this paper. From the field experimental data, nutrient requirement (NR), contribution of nutrients from soil (Cs), fertilizer (Cf) and farmyard manure (Cfym) were computed. The nutrient requirement for producing one quintal of rice grain yield was worked out as 1.50 kg of N, 0.68 kg of P 2O5 and 1.97 kg of K2O. The contributions of available N, P2O5 and K2O towards total N, P and K uptake by rice from soil and fertilizer were 16.14, 38.40, 16.57 and 35.70, 33.17, 60.17 per cent respectively while the contribution from manure was 24.24, 9.52 and 33.89 per cent respectively. The estimated per cent contribution of N, P2O5 and K2O from FYM (Cfym) was 24.26, 9.52 and 33.89 per cent respectively. Using the basic parameters, fertiliser prescription equations were developed for rabi season and ready reckoner of fertiliser doses were formulated. The contribution of FYM@12.5 t ha-1 when applied along with recommended doses of NP&K fertilisers was found to be 40, 20 and 32 kg ha -1 of fertiliser N, P2O5 and K2O respectively. Introduction Rice, a global grain is the king crop of Asia and staple food grain for more than half of the world population. The demand for rice is expected to rise due to increase in population and reduction in area under rice cultivation in next 15-20 years. Water scarcity appears to be one of the major constraints affecting rice production across the globe. More than 80 percent of the fresh water resources in Asia are used for agriculture and about a half of it is 1134 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 used for rice production (Mahender Kumar et al., 2013). Available estimates indicate that fresh water availability in India will be reduced to one-third by 2025. Hence, producing more rice for every drop of water, as well as with less land and minimum fertilizer if possible, is important for sustainability of rice production systems. System of Rice Intensification (SRI) is such holistic agro ecological crop management technique seeking alternatives to the conventional high input oriented agriculture, through effective integration of crop, soil, water and nutrient. This methodology increases the productivity of irrigated rice by changing the management of plants, soil, water and nutrients resulting in both healthy soil and plants, supported by greater root growth and the soil microbial abundance and diversity. Fertilizer is one of the inputs which bring quantum jump in the yield of rice. The nutrient uptake by rice plant is different from other field crops. To improve the production efficiency of rice and to synchronize the application of nutrients with the demand of the plant, it is necessary to apply required dose of NPK fertilizers. Further, the Indian agriculture is operating on a net negative balance of 8-10 mt of NPK per annum. Use of fertilizers by the farmers without information on soil fertility status and nutrient requirement by the crop result in adverse effect on soil and crop either by nutrient toxicity or deficiency. In this context, soil test based fertilizer recommendation plays a vital role in ensuring balanced nutrition to crops and also in preventing wasteful expenditure on the use of costly fertilizer. At this juncture, Inductive cum Targeted yield model provides a scientific basis for balanced fertilization and balance between applied nutrients and soil available nutrients. Addition of Integrated Plant Nutrition System (IPNS) to this concept ensures balanced fertilization by application of inorganic and organic sources of nutrients. Keeping the above points in view the present investigation was contemplated adopting the Inductive cum Targeted Yield model so as to develop basic data of nutrient requirement and contribution of nutrients to total uptake from different sources and to develop fertilizer N, P and K prescription equations and farmer friendly ready reckoner to prescribe fertilizers in rice crop under SRI for rabi season on an Alfisol. Materials and Methods Basic concept The methodology adopted in this study is the prescription procedure outlined by Truog (1960) and modified by Ramamoorthy et al., (1967) as ―Inductive cum Targeted yield model‖ which provides a scientific basis for balanced fertilization and balance between applied nutrients and soil available nutrients forms. Operational range of variation in soil fertility was created deliberately to generate data covering appropriate range of values for each controllable variable (fertilizer dose) at different levels of uncontrollable variable (soil fertility) which could not be expected to occur at one place normally. Hence, in order to create fertility variations in the same field, a gradient experiment was conducted prior to the test crop experiment to reduce the heterogeneity in the soil population studied, management practices adopted and climatic conditions prevailing. After confirming the creation of soil fertility gradients, test crop experiment was conducted for developing fertilizer prescription. In Tamil Nadu, STCR-IPNS (Integrated Plant Nutrition System) recommendations have been developed for 29 crops comprising cereals, millets, pulses, oilseeds, sugarcane, cotton, vegetables, spices and medicinal crops on 16 soil series (Santhi et al., 2017). 1135 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 Soil characteristics The field experiments were conducted at the wetland of wetlands farm, TNAU Coimbatore, Tamil Nadu on Noyyal soil series (Clay loamy, mixed isohyperthermic, Typic Haplustalf) belongs to Alfisol. The soil was clay loam in texture, moderately alkaline in reaction (pH 8.2) and non - saline (EC 0.49 dS m-1). The initial soil fertility status showed low available N (250 kg ha-1, medium available P (19.9 kg ha-1) and high available K (560 kg ha-1). The available Zn and Cu were in the deficient status (0.63 and 0.33mg kg-1 respectively) while available Mn and Fe were in the sufficient status (5.52 and 11.27 mg kg-1). Treatments and soil and plant analysis The approved treatment structure and lay out design as followed in the All India Coordinated Research Project for Investigations on Soil Test Crop Response Correlation based on ―Inductive cum Targeted yield model‖ was adopted in the present investigation. There were two phases of field experimentation viz., gradient and test crop experiment. Fertility gradient experiment To create operational range of variation in soil fertility, the experimental field was divided into three equal strips, N0P0K0 (strip I), N1P1K1 (strip II) and N2P2K2 (strip III). N1 is the nitrogen dose equivalent to blanket recommendation for the gradient crop of rice. The P1 and K1 are the P and K fixing capacities of the soils respectively. The first strip received no fertiliser (N0P0K0), the second strip received N1 as blanket dose and P1 and K1 as P and K fixing capacities of the soil and the third strip received twice the dose of second strip and a gradient crop of rice (var.ADT 43) was grown. Eight pre-sowing and post-harvest soil samples were collected from each fertility strip and analysed for alkaline KMnO4-N, Olsen -P and NH4OAc-K. At harvest, plant samples were collected, processed and analysed for N, P and K contents and NPK uptake was computed. Test crop experiment After confirming the establishment of fertility gradients in the experimental field, in the second phase of the field experiment, each strip was divided into 24 plots, and initial soil samples were collected from each plot and analysed for alkaline KMnO4-N (Subbiah and Asija, 1956), Olsen-P (Olsen et al., 1954) and NH4OAc-K (Stanford and English, 1949). The experiment was laid out in a fractional factorial design comprising twenty four treatments and the test crop experiment with rice variety CO (R) 49 was conducted under SRI with four levels each of N (0, 75, 150 and 225 kg ha-1), P2O5 (0, 25, 50 and 75 kg ha-1) and K2O (0, 25, 50 and 75 kg ha-1) and three levels of FYM (0, 6.25 and 12.5 t ha-1). The SRI practices were followed viz., planting of young seedlings, single seedling, wider spacing in a square pattern (25 x 25 cm), intermittent irrigation, conoweeding with the aim of providing optimal growth conditions for the plant, to get better performance in terms of yield and input productivity. The experiment was conducted as per the approved guidelines of AICRP-STCR and fertiliser prescriptions were developed. The IPNS treatments viz., NPK alone, NPK+ FYM @ 6.25 t ha-1 and NPK + FYM @ 12.5 t ha-1 were superimposed across the strips. There were 21 fertiliser treatments along with three controls which were randomized in each strip in such a way that all the treatments occurred in both the directions. FYM was applied basally and fertiliser doses were imposed as per the 1136 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 treatments. Twenty five per cent of N and K2O and full dose of P2O5 were applied basally before transplantation and remaining N and K2O were applied in three equal splits viz., tillering, panicle initiation and heading stages. Routine agronomic practices were carried out periodically. The crop was grown to maturity, harvested and plot wise grain and straw yield were recorded. Plant and post-harvest soil samples were collected from each plot. The plant samples were processed and analyzed for N (Humphries, 1956), P and K contents (Jackson, 1973) and NPK uptake by rice was computed using the drymatter yield. Making use of the data on pre-sowing soil test values for available N, P and K, grain yield, total uptake of N, P and K, and doses of fertiliser N, P2O5 and K2O applied, the basic parameters viz., nutrient requirement (NR), contribution of nutrients from soil (Cs), fertiliser (Cf) and farmyard manure (Cfym) were calculated as outlined by Ramamoorthy et al., (1967). i. Nutrient requirement (NR) kg q-1 Kg N/ P2O5/ K2O required per quintal of grain = production Total uptake of N/ P2O5/ K2O (kg ha-1) Grain yield (q ha-1) ii. Per cent contribution of nutrients from soil to total nutrient uptake (Cs) Total uptake of N/ P2O5/ K2O in control plot (kg ha-1) Per cent contribution of N/ P2O5/ K2O from soil = x 100 Soil test value for available N/ P2O5/ K2O in control plot (kg ha-1) iii. Per cent contribution of nutrients from fertiliser to total uptake (Cf) Per cent contribution of N/ P2O5/ K2O from fertiliser = Total uptake Soil test value for of N/ P2O5/ available N/ P2O5/ x Average Cs K2O in - K2O in treated plot treated plot (kg ha-1) -1 (kg ha ) Fertiliser N/ P2O5/ K2O applied (kg ha-1) x 100 iv. Percent contribution of nutrients from organic manure to total uptake (Co) Percent contribution from FYM (Cfym) Percent contribution of N/P/K from FYM = Total uptake Soil test value for of N/P/K in available N/P/K in x Average Cs FYM treated - FYM treated plot plot (kg ha-1) (kg ha-1) Nutrient N/P/K added through FYM (kg ha-1) 1137 x 100 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 These parameters were used for developing fertiliser prescription equations for deriving fertilisers doses, and the soil test based fertiliser recommendations were prescribed in the form of a ready reckoner for desired yield target of type rice under NPK alone and under IPNS. i) Fertiliser nitrogen (FN) NR Cs FN = T Cf /100 Cf NR Cs FN = T Cf /100 Cf ii) Fertiliser phosphorus (FP2O5) NR Cs FP2O5 = T Cf /100 Cf NR Cs FP2O5 = T Cf /100 Cf iii) Fertiliser potassium (FK2O) NR Cs FK2O = T Cf /100 Cf NR Cs FK2O = T Cf /100 Cf Fertiliser prescription equations Making use of these parameters, the fertiliser prescription equations (FPEs) were developed for rice (rabi season) as furnished below. SN SN - Cfym Cf x 2.29 x SP x 2.29 x SP - x 1.21 x SK x 1.21 x SK - where, FN, FP2O5 and FK2O are fertiliser N, P2O5 and K2O in kg ha-1, respectively; NR is nutrient requirement (N or P2O5 or K2O) in kg q-1, Cs is per cent contribution of nutrients from soil, Cf is per cent contribution of nutrients from fertiliser, Cfym is percent contribution of nutrients from FYM, T is the yield target in q ha-1; SN,SP and SK respectively are alkaline KMnO4-N, Olsen-P and NH4OAc-K in kg ha-1 and ON, OP and OK are the quantities of N, P and K in kg ha-1 supplied through FYM. These equations serve as a basis for predicting fertiliser doses for specific yield targets (T) of rabi rice for varied soil available nutrient levels. Results and Discussion Soil fertility status The data on initial soil test values of the test crop experiment revealed that, the mean KMnO4-N was 230, 262 and 296 kg ha-1, ON Cfym Cf Cfym Cf x 2.29 x 1.21 x OP x OK respectively in strips I, II and III. The mean Olsen-P values were 18.0, 30, 3 and 38.5 kg ha-1 respectively in strips I to III and the mean NH4OAc-K values were 539, 588 and 620 kg ha-1 in strips I, II and III, respectively (Table 1). The per cent increase in soil available N of strip II over strip I was 13.9 and that of strip III over strip II and strip I were 13.0 and 28.7 respectively. Similarly, the respective per cent increase values for Olsen –P and NH4OAc-K were 68.3, 27.1 and 113.9 and 9.1,5.4 and 15.0 respectively. In the present investigation, the existence of operational range of soil test values for available N, P and K status was clearly depicted from the variation in initial soil available nutrient status which is a prerequisite and underlying principle for calculating the basic parameters and developing fertilizer prescription equations for calibrating the fertiliser doses for specific yield target of rice. Similar type of development of fertility gradient for the 1138 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 existence of operational range of available N, P and K status was reported by reported by Mahajan et al., (2013) for wheat and Verma et al., (2017) for mustard. Due to the application of graded levels of fertilisers, notable fertility variations were recorded in various strips Grain yield and Nutrient Uptake The range and mean values (Table 2) indicated that the grain yield of rabi rice ranged from 2680 kg ha-1 in strip I to 7440 kg ha-1 in strip III where the lowest yield was recorded in absolute control and the highest yield was recorded in N225P75K75 + FYM @ 12.5 t ha-1 with mean grain yield of 5156, 5490 and 5733 kg ha-1, respectively in strips I, II and III. The N uptake by rice varied from 39.0 to 120 kg ha-1; P uptake from 6.2 to 24.7 kg ha-1 and K uptake from 62to 117 kg ha-1. The total N, P and K uptake was observed to be the highest in strip III followed by strip II and it was the least in strip I. Irrespective of the strips, NPK plus FYM @ 12.5 t ha-1 plots, the yield ranged from 3630 to 7440 kg ha-1 with a mean of 6030 kg ha-1 recording an increase of 115.4 per cent over absolute control. In NPK plus FYM @ 12.5 t ha-1 applied plots, the N, P and K uptake ranged from 52.8 to 126.0; 8.8 to 23.7 and 69.8 to 117.0 kg ha-1 with mean of 96.0, 18.4 and 96.3 kg ha-1 respectively. The N, P and K uptake in NPK plus FYM @ 12.5 t ha-1 applied plots recorded an increase of 138.2, 76.9 and 47.4 per cent over absolute control and 82.1, 37.3 and 22.7 per cent over FYM alone @ 12.5 t ha-1, respectively. The increased yield and uptake might be due to the improvement in physico-chemical properties of soil, solubilisation of native nutrients, supply of the nutrients in balanced amount and slow release of nutrients through integrated use of FYM. Similar, findings were reported by Antaryami Mishra et al., (2013) for rice tomato sequence and Saraswathi et al., (2015) in ragi. parameters for developing fertilizer prescription equations for rabi rice are nutrient requirement (NR) in kg per quintal of grain yield, per cent contribution of available NPK from soil (Cs), fertilizers (Cf) and farmyard manure (Cfym). Making use of data on the grain yield of rice, total uptake of N, P and K, initial soil test values for available N, P and K and doses of fertilizer N, P2O5 and K2O applied, the basic parameters were computed. Nutrient requirement Nutrient requirement to produce one quintal (100 kgs) of rice grain was 1.50 kg of N, 0.68 kg of P2O5 and 1.97 kg of K2O. Synchronized application of adequate amount of nutrients according to the demand of the plant is a prerequisite to improve the production efficiency of any crop. In rice crop, there was progressive increase in grain yield and nutrient uptake with the increased doses of applied N, P2O5 and K2O and FYM. At the same time, application of nutrients especially major nutrients like N, P and K at an improper ratio can result in high dry matter production but not better harvest index. The order of nutrient requirement in the present investigation was K>N>P. The requirement of K2O was 1.31 times higher than N and 2.89 times higher than P2O5. Similar trend of nutrient requirement for N, P2O5 and K2O was also reported by Verma et al., (2017) for mustard and Santhi et al., (1999) for rice. Experiments conducted at Coimbatore have shown that under the same nutrient application level, SRI plants take up more nutrients and produce more grain weight per unit of nutrient uptake (Thiyagarajan and Biksham Gujja, 2013) This nutrient recovery by the plant is due to extensive root systems of SRI plants which remove more nutrients from the soil. Basic parameters (Table 1) Per cent contribution of nutrients from soil, fertilizer and FYM In the targeted yield model, the basic In the present study, it was found that the soil 1139 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 has contributed 16.14 per cent of available N, 38.40 per cent of available P and 16.57 per cent of available K respectively towards the total N, P and K uptake by rice. Among the three nutrients, the per cent contribution from soil was found to be higher for P followed by K and N. With regard to N and K2O, comparatively lower Cs was recorded which might be due to the preferential nature of rice towards the applied N and K2O than the native N and K. The per cent contribution from fertilizer nutrients (Cf) towards the total uptake by rice was 35.70, 33.17 and 60.17 per cent, respectively for N, P2O5 and K2O and followed the order of K2O > N > P2O5. The per cent contribution of nutrients from fertilizers (Cf) to total uptake followed the order of K2O > N > P2O5 as that of nutrient requirement. The study clearly revealed the fact that the magnitude of contribution by fertilizer K2O was 1.69 times higher than N and 1.81 times as that of P2O5. With regard to N and K2O, comparatively more contribution was recorded from fertilizers than from the soil. However, STCR-NPK alone FN FP2O5 FK2O = = = 4.20 T- 0.45 SN 2.05 T- 2.65 SP 2.85 T- 0.29 SK in the case of P2O5, the contribution was more from soil than from fertiliser. The estimated per cent contribution of N, P2O5 and K2O from FYM (Cfym) was 24.24, 9.52 and 33.89 respectively for rice which indicated that relatively higher contribution was recorded for K2O followed by N and P2O5 for rice. The response yardstick recorded was 79.71 kg kg-1. The contribution of nutrients from FYM for rice also followed the order as: K>N>P indicated that relatively higher contribution was recorded for K2O followed by N and P2O5. The present findings were corroborated with the findings of Santhi et al., (1999) in rice and Sellamuthu et al., (2016) in rainfed maize. Fertilizer prescription equations for rice (rabi season) Soil test based fertilizer prescription equations for desired yield target of rice for rabi season were formulated using the basic parameters and are furnished below: STCR-IPNS (NPK + FYM ) FN = 4.20 T- 0.45 SN - 0.68 ON FP2O5 = 2.05 T- 2.65 SP - 0.66 OP FK2O = 2.85 T- 0.29 SK - 0.59 OK where, FN, FP2O5 and FK2O are fertilizer N, P2O5 and K2O in kg ha-1, respectively; T is the yield target in q ha-1; SN, SP and SK respectively are alkaline KMnO4-N, Olsen-P and NH4OAc-K in kg ha-1 and ON, OP and OK are the quantities of N, P and K in kg ha-1 supplied through FYM. Table.1 Nutrient requirement, per cent contribution of nutrients from soil, fertilizer and FYM for rice (rabi) Parameters N 1.50 16.14 35.70 24.24 -1 Nutrient requirement (kg q ) Per cent contribution from soil Per cent contribution from fertilizers Per cent contribution from FYM (Cfym) 1140 Basic data P2O5 0.68 38.40 33.17 9.52 K2O 1.97 16.57 69.16 33.89 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 Table.2 Initial soil available NPK, yield and NPK uptake by rabi rice (kg ha-1) Parameters (kg ha-1) Strip I Range 224-235 15.0-20.4 502-549 2680-6830 39.0 -102.6 6.2-20.8 62.0-107.6 KMnO4 –N Olsen–P NH4OAc-K Grain yield N uptake P uptake K uptake Strip II Mean 230 18.0 539 5156 79.4 14.0 86.5 Range 255-266 25.5-33.3 570-595 2820-7010 40.0-124.0 9.9-22.4 64.0-108.5 Strip III Mean 262 30.3 588 5490 90.5 17.3 91.7 Range 290-300 33.7-43.4 601-627 2900-7440 41.8-120.0 15.0-24.7 70.0-117 Mean 296 38.5 620 5733 90.3 19.3 95.5 Table.3 Soil test based fertilizer prescription for yield targets rice 7 and 8 t ha-1 (kg ha-1) Soil test values (kg ha-1) SN 200 220 240 260 280 300 320 SP 18 20 22 24 26 28 30 SK 300 350 400 450 500 550 600 NPK alone 7 (t ha-1) FN FP2O5 204 96 195 91 186 85 177 80 168 75 159 69 150 64 NPK +FYM @ 12.5 t ha-1 8 7 8 -1 -1 (t ha ) (t ha ) (t ha-1) FK2O FN FP2O5 FK2O FN FP2O5 FK2O FN FP2O5 FK2O 100 246 100 100 164 76 81 206 96 100 98 237 100 100 155 71 66 197 91 95 84 228 100 100 146 65 52 188 86 80 69 219 100 98 137 60 37 179 80 66 55 210 95 83 128 55 25 170 75 51 40 201 90 69 119 49 25 161 70 37 25 192 85 54 110 44 25 152 65 25 Fertilizer prescription under IPNS for desired yield target of rice Fertilizer doses for desired yield target of 7 and 8 t ha-1 of rabi rice were worked out for a range of soil test values and ready reckoner was prepared. For achieving an yield target of 8 t ha-1 of grain yield with a soil test value of 280, 28 and 500 kg ha-1 of KMnO4-N, OlsenP and NH4OAc-K, the fertilizer N, P2O5 and K2O doses required were 168, 69 and 55 kg ha-1, respectively under NPK alone and 128, 49 and 25 kg ha-1 under IPNS Using the fertilizer prescription equations under IPNS, the extent of saving of chemical fertilizers for rabi rice was computed. The results showed that with the application of FYM @ 12.5 t ha-1 (with 28% moisture, 0.65, 0.33 and 0.60 % NPK respectively), there was a saving of 40, 20 and 32 kg of fertilizer N, P2O5 and K2O respectively. The NPK fertilizers requirement decreased under IPNS and also with increasing soil fertility levels with reference to NPK and increased with increase in yield targets. These could be achieved by integrated use of FYM with NPK fertilizers. The role of FYM is multidimensional ranging from building up of organic matter, maintaining favourable soil physical properties, priming effect and balanced supply of nutrients. 1141 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 1134-1143 The supremacy of fertilizer recommendations based on inductive approach, a refined method of fertilizer recommendation for varying soil test values to obtain higher response ratios and benefit:cost ratios over a wide range of agro-ecological regions in different crops has been highlighted by Dey (2015). From the ready reckoner farmers can choose the desired yield targets according to their investment capabilities and availability of organic manures. In conclusion, in the present STCR-IPNS based investigation, fertilizer prescription equations were developed for rice (rabi season) under SRI on Typic Haplustalf considering the nutrient requirement, percentage contribution of nutrients from soil, fertilizer and FYM towards total uptake. Targeted yield equations generated from STCR-IPNS technology envisages a balanced nutrient supply to rice and ensures not only sustainable crop production but also economise the use of costly fertilizer inputs. Hence, practice of fertilizing crops using fertilizer prescription equations needs to be popularized among farmers to achieve higher productivity, nutrient use efficiencies and profitability. The fertilizer prescription equations developed using this model can be applied to Alfisols of all tropical regions by substituting the soil nutrient status of the particular field. Moreover, the methodology adopted in the present investigation viz., the prescription procedure outlined by Truog (1960) and modified by Ramamoorthy et al., (1967) as ―Inductive cum Targeted yield model‖ can very well be used to derive fertilizer prescription equations for any field or horticultural crop on any soil series. Adoption of fertilizer prescription equations along with integrated plant nutrition system and management strategies would enhance the input use efficiency and crop productivity. Acknowledgement The authors gratefully acknowledge the Indian Council of Agricultural Research, New Delhi and Indian Institute of Soil Science, Bhopal and Tamil Nadu Agricultural University, Coimbatore for funding and implementing the All India Coordinated Research Project for Investigations on Soil Test Crop Response Correlation (AICRP-STCR) at Tamil Nadu Agricultural University, Coimbatore. References Antaryami Mishra., B. B. Dash, S. K. Nanda, D. Das and Pradip Dey. 2013. Soil Test Based Fertilizer Recommendation for Targeted Yield of Tomato (Lycopersicon esculentum) under RiceTomato Cropping System in an Ustochrept of Odisha. Environment & Ecology 31 (2A): 655—658 Dey.P. 2015. Soil Test Crop Response: What Can Be Learnt? In Book of extended summaries. 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Thiyagarajan T.M and Biksham Gujja. 2013. Transforming rice production with SRI (System of Rice Intensification) knowledge and practice. Nationa consortium on SRI (NCS). PP. 92 Truog, E.1960. Fifty years of soil testing. Trans 7th Intl. Congr. Soil Sci. Vol. III Commission IV paper No.7: pp: 46-53. Verma, M., Y.V.Singh, P. Dey and A. Babu. 2017. Soil Test based Fertilizer Recommendation for Mustard (Brassica juncea L.) in Eastern Plain Zone of Uttar Pradesh, India. Int.J.Curr. Microbiol.App.Sci., 6(2): 155-161 How to cite this article: Maragatham, S., Santhi, R., Sellamuthu, K.M. and Pradip Dey. 2018. Yield Targeting for Rice under SRI on Alfisols of Tamil Nadu through Soil Test based Integrated Plant Nutrition System. Int.J.Curr.Microbiol.App.Sci. 7(08): 1134-1143. doi: https://doi.org/10.20546/ijcmas.2018.708.129 1143