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Background: In the era of precision agriculture, application of fertilizer based on soil testing is an essential tool to prescribe nutrient doses for crops to improve nutrient use efficiency and yield of hybrid castor. Methods: Field experiment was conducted in 2021 at the Tapioca and Castor Research Station, Yethapur, region near Salem city, Tamil Nadu, India (11°35'N, 78°29'E). By adopting inductive cum targeted yield model fertilizer prescription equation (FPEs) were developed for hybrid castor under irrigated condition for Alfisol soil order. Initially soil fertility gradient were established with respect to soil available N, P and K nutrients and twenty four treatment were imposed in three fertility strips under factorial randomized design. The basic parameters [nutrient requirement (NR) and nutrients contributions from soil (Cs), fertilizer (Cf) and farmyard manure (Co)] were calculated from the field experimental data. Result: The nutrient required for producing one quintal of hybrid castor seed yield was evaluated as 3.20 kg of nitrogen, 1.23 kg of phosphorus pentoxide (P2O5) and 3.28 kg of potassium oxide (K2O). The study revealed that soil nutrient contribution was high in case of available phosphorus (41.87%), available nitrogen (21.56%) and available potassium (19.12%) respectively toward P, N and K nutrient uptake by hybrid castor. The nutrient contribution from farmyard manure (Co) towards the total uptake was 21.40% of N, 10.35% of P2O5 and 26.06 % of K2O respectively. Using basic data, FPEs were developed for hybrid castor and ready reckoner were developed for operational range of soil test values for desired yield target under NPK alone and IPNS (NPK and FYM). [ABSTRACT FROM AUTHOR]

Background: Barnyard millet is one of the significant small millets cultivated in India. It has provided a good source of nutrients. Its production is low in low fertile soil. For that study undertaken into supplying balanced nutrition to achieve maximum yield by following soil test crop response-based fertilizer prescription equation. Methods: The Inductive methodology adopted in the field experiment for developing a scientific basis of fertilizer prescription for barnyard millet was performed on Periyanaickenpalayam soil series of Inceptisol soil order of Tamil Nadu during 2019-2020. The initial soil available nutrient status, grain yield, total nutrient uptake by barnyard millet and fertilizer N, P2O5 and K2O and FYM applied were taken into account for calculating four basic parameters for developing fertilizer prescription equation viz., nutrient requirement (NR) to produce 100 kg of barnyard millet grains, the contribution of nutrients from soil (Cs), fertilizer (Cf) and FYM (Cfym). Result: The fertilizer prescription equations and ready reckoner were developed to prescribe fertilizer dosage for a range of soil test values for specific yield target of barnyard millet on Inceptisol. It can be adopted on the Periyanaickenpalayam soil series of Tamil Nadu and also in regions with allied soil types. [ABSTRACT FROM AUTHOR]

The soil test value is based on the soil test-based fertilizer prescription/recommendation equation. Each crop harvesting after the next crop is necessary to analyze the soil. Therefore, it is necessary to develop an alternative technique to predict postharvest soil tests after the harvest of every crop. For that a study was conducted in mixed black calcareous soils at Tamil Nadu agricultural University, Coimbatore to develop the post-harvest prediction equations for available nitrogen, phosphorus and potassium in barnyard millet cropping sequence based on a multiple regression model by considering post-harvest soil test value as the dependent variable and initial available nutrients, fertilizer doses and crop yield or crop nutrient uptake as an independent variables. The developed model was validated by computing R2 value, RMSE (root means square error), RE (relative error), and the ratio of performance to deviation (RPD) and the developed model was found to be valid. Using the validated model, post-harvest soil test values were predicted. A fertilizer recommendation was made for blackgram based on predicted postharvest soil test values in the barnyard millet-blackgram cropping sequence. The predicted soil test values were compared with actual soil test values and it revealed that the developed model is fairly accurate and best-fitted with more precision. The predicted post-harvest soil test values of barnyard millet could be used in order to prescribe fertilizer for desired yield targets for subsequent crops. [ABSTRACT FROM AUTHOR]

An insight into the balanced crop nutrition and efficient irrigation will be rewarding to attain profitable bulb yield of shallow-rooted and high nutrient requiring aggregatum onion. To develop fertilizer prescription equations(FPEs) for aggregatum onion under drip fertigation by encompassing the Soil Test Crop Response approach (STCR), a field experiment was conducted in Palaviduthi soil series with 15 treatments viz., Absolute control (T1), Blanket recommendation (60:60:30) + Farm Yard Manure (FYM) @ 12.5 t ha-1(T2), STCR based NPK fertilizer recommendation (STCR-NPK) for the targeted yield of 14 (T3),15 (T4),16 t ha-1 (T5), FYM @ 6.25 (T6), 12.5 t ha-1 (T7), STCR-NPK+FYM @ 12.5 t ha-1 for the targeted yield of 14 (T8),15 (T9),16 t ha-1 (T10), Biocompost @ 2.5 (T11), 5 t ha-1 (T12) and STCR-NPK+Biocompost @ 5 t ha-1 for the targeted yield of 14 (T13),15 (T14),16 t ha-1 (T15). The results revealed that T10 was more supercilious than others. The basic parameters were deliberated from the experimental data on total nutrient uptake, initial soil fertility status, applied fertilizer doses. The aggregatum onion (variety CO 4) required 0.43, 0.32, 0.45 Kg of N, P2O5, K2O to produce one quintal of bulb yield. The percent contribution of nutrients from soil and fertilizer was 14.01, 54.57 for N, 35.11,50.50 for P2O5 and 12.69, 70.12 for K2O, respectively. The contribution of N, P2O5, K2O from FYM and biocompost were 41.02, 16.23, 41.53 and 47.98, 15.87, 49.56 percent sequentially. Based on the above parameters, the fertilizer prescription equations were formulated for aggregatum onion under drip fertigation in Palaviduthi soil series. [ABSTRACT FROM AUTHOR]

Soil test crop response (STCR) based fertilizer prescription for desired yield target of pearl millet was developed under integrated plant nutrition system (STCR-IPNS) on Periyanaickenpalayam soil series (Vertic Ustropept) of Tamil Nadu, India. The present study was undertaken to validate the developed fertilizer prescription equations (FPEs) through field experiment in Western Zone of Tamil Nadu. The results emanated from the validation experiment proved the validity of the FPEs for pearl millet by recording the aimed yield targets within±10% variation. Among the treatments, STCR-IPNS-4.0 t/ha of pearl millet has proved its superiority and recorded a yield increase of 59.8, 18.7 and 89.3%, respectively over blanket, blanket plus farm yard manure (FYM) @ 12.5 t/ha and farmer's practice. The increase in response ratio due to STCR-IPNS-4.0 t/ha over blanket, blanket plus FYM @ 12.5 t/ha and farmer's practice was 1.0, 0.9 and 1.5 kg/kg, respectively, and that of benefits : cost ratio was 0.65, 0.28 and 0.79, respectively. Soil test-based fertilization resulted in increased yield, economic returns, protein content, protein yield, and either built-up or sustenance of soil fertility and the magnitude of built-up was higher with STCR-IPNS as compared to STCR-NPK alone, blanket recommendations, farmer's practice and control. [ABSTRACT FROM AUTHOR]

Field experiments were conducted based on Inductive cum targeted yield concept on Typic Haplustert soils (Pilamedu series - black calcareous) to predict the post-harvest soil test values for prescribing soil test crop response based fertilizer doses under Integrated Plant Nutrition System (STCR-IPNS) for maize based cropping sequence. The experiment comprised of 24 treatments with four levels each of N (0,100,200 and 300 kg ha-1), P2O5 (0,40,80 and120 kg ha-1) and K2O (0,40,80 and120 kg ha-1) and three levels of FYM (0, 6.25 and 12.5 t ha-1) for the test crop maize (TNAU Maize hybrid CO 6) laid out in fractional factorial design. Making use of the experimental data on initial and post-harvest soil test values, fertilizer doses and the grain yield obtained or uptake of N,P and K by maize, Post-Harvest Soil Test Values (PHSTVs) prediction equations with high R2 values (>0.90) were developed, which could be used with confidence for the prediction of post-harvest KMnO4-N,Olsen-P and NH4OAc-K. Using the predicted PHSTVs after kharif maize, soil test based fertilizer prescription for desired yield target of succeeding crop viz., cotton could be prescribed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A study on Soil Test Crop Response based Integrated Plant Nutrition System (STCR - IPNS) were conducted adopting an Inductive cum Targeted yield model in non-calcareous sandy loam soils of Lithic Haplusteptat Regional Research Station, Tamil Nadu Agricultural University, Paiyur, Tamil Nadu during Kharif 2013 in orderto develop fertilizer prescriptions equation (FPEs) through IPNS for the desired yield targets of rice under SRI technique. A ready reckoner of fertilizer doses at varying soil test value, for attaining 6 to 9 t ha-1 target grain yield of rice has been worked out. Using these equations a validation trial was conducted on Kharif 2014 at this station. The grain yield of rice ranged from 2.54 t ha-1 in absolute control to 8.65 t ha-1 in STCR-IPNS-9 t ha-1. The STCR-IPNS @ 8 t ha-1 was effective and economical as compare with any other treatments. The deviation recorded in the achievement of targets aimed was within the range of ± 10 per cent (90 - 110 %) proving the validity of the FPEs. The STCR treatments recorded relatively higher response ratio (RR) and benefit-cost ratio (BCR) over blanket and farmer's practice and STCR-IPNS treatments recorded relatively higher RR and BCR over STCR-NPK alone treatments. Post-harvest soil tests for NPK revealed that there was maintenance of soil fertility. The STCR-IPNS @ 8 t ha-1 was effective and economical as compare with any other treatments. Thus, the Inductive cum Targeted yield model used to develop fertilizer prescription equations provides a strong basis for soil fertility maintenance consistent with high productivity and efficient nutrient management for sustainable and enduring Agriculture. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Soil test crop response (STCR) based fertilizer prescription for desired yield target of wheat was developed under Integrated Plant Nutrition System (STCR-IPNS) on Periyanaickepalayam soil series (Vertic Ustropept) of Tamil Nadu. On-farm testing of fertilizer prescription equations are essential to demonstrate the effectiveness of technology delivery to the stake holders in need. The present study was undertaken in six locations to evaluate the model through field experiments in Western Zone of Tamil Nadu. The treatments included control, blanket recommendation, soil test crop response (STCR) based fertilizer dose for an yield target of 3.0 and 4.0 t/ha, STCR-IPNS based fertilizer dose for an yield target of 3.0 and 4.0 t/ha and farmer's practice. Based on the initial soil test values of available N, P and K and the quantities of N, P and K contributed through farm yard manure (FYM), fertilizer doses were calculated and applied for STCR and STCR-IPNS treatments for the respective yield targets. The treatments were imposed and cultivation practices were carried out periodically and the grain yield was recorded at harvest. Using the data on grain yield and fertilizer doses applied, per cent achievement and response ratio (RR) were worked out. Post-harvest soil samples were collected and analyzed for available N, P and K status. The results of the experiments indicated that in all the six locations, the per cent achievement of the targeted yield was within±10% variation proving the validity of the equations for prescribing integrated fertilizer doses for wheat. The highest mean per cent achievement was recorded in the yield target of 4.0 t/ha (101.2) under STCR-IPNS followed by STCR-NPK alone 4.0 t/ha. The highest mean yield was recorded in STCR-IPNS-4.0 t/ha (4047 kg/ha) recording an increase of 62.1% over blanket recommendation. Among the treatments, STCR-IPNS recorded relatively higher RR than other treatments and the highest mean RR of 6.90 kg/kgwas recorded under STCR-IPNS 4.0 t/ha. The highest benefit : cost ratio (1.81) was also recorded in STCR-IPNS 4.0 t/ha. The post-harvest soil available NPK indicated the build up and maintenance of soil fertility due to soil test based fertilizer recommendation under IPNS. The fertilizer prescription equations developed for wheat under IPNS can be recommended for mixed black calcareous soils of Tamil Nadu (Vertic Ustropept) for achieving an yield target of 4.0 t/ha with sustained soil fertility and it can be extrapolated to other agro-climatic zones of Tamil Nadu on similar and allied soil types. [ABSTRACT FROM AUTHOR]

Soil Test Crop Response correlation studies were carried out in maize under Integrated Plant Nutrition System (STCR-IPNS) on Typic Rhodustalf of Tamil Nadu, adopting "Inductive cum Targeted yield model". The basic parameters for the "Targeted yield model" viz. nutrient requirement (NR), contribution of nutrients from soil (Cs), fertilizer (Cf) and farmyard manure (Cfym) were computed from field experimental data. Using these parameters, the fertiliser prescription equations were developed under IPNS and ready reckoner of fertiliser doses were formulated for desired yield target of maize for a range of soil test values. The quantity of fertilizer nutrients that could be saved due to the application of FYM @ 12.5 t ha-1 was assessed to the tune of 40, 20 and 26 kg fertilizer N, P2O5 and K2O respectively, when applied along with the NPK fertilizers. The per cent reduction in fertilizer N, P2O5 and K2O under IPNS increased with increasing soil available NPK. [ABSTRACT FROM AUTHOR]

Soil test based fertilizer prescriptions for desired yield target of wheat were developed under Integrated Plant Nutrition System (IPNS) for Ooty soil series (Typic Haplohumult) of Tamil Nadu. To validate the equations, experiments were conducted in Salem and Namakkal districts at farmers holding on similar soil series. The results revealed that the per cent achievement of the aimed yield target was within ± 10 per cent variation confirming the validity of the equations. STCR treatments recorded significantly higher yield, Response Ratio (RR) and BCR over blanket while STCR - IPNS treatments recorded relatively higher yield, RR and BCR over STCR-NPK alone treatments. The highest mean yield of 41.63 q ha-1 was recorded with STCR-IPNS 40 q ha-1 with an increase of 55.8 per cent over blanket. Post - harvest soil fertility with respect to available N, P and K revealed that there was sustainability of soil fertility in STCR treatments. Therefore soil test based fertilizer prescription can be recommended to hilly and foothill areas of Tamil Nadu for achieving 40 q ha-1 of wheat. [ABSTRACT FROM AUTHOR]

Field experiments were conducted in Southern and Western Zones of Tamil Nadu to evaluate the Soil Test Crop Response based fertilizer prescription model under Integrated Plant Nutrition System (STCR-IPNS) for desired yield targets of radish on red calcareous soils (Palathurai series-Typic Rhodustalf). The treatments include control, blanket recommendation, soil test crop response (STCR) based fertilizer dose for an yield target of 40 t ha-1 and 50 t ha-1, STCR-IPNS based fertilizer dose for an yield target of 40 t ha-1 and 50 t ha-1 and farmer's practice. The results of the experiments indicated that, in all the six trials, the per cent achievement of the targeted yield was within ± 10 per cent variation proving the validity of the equations for prescribing integrated fertilizer doses for radish. The highest mean per cent achievement was recorded with STCR - IPNS - 50 t ha-1 (101.3) followed by STCR-NPK alone 50 t ha-1. The highest mean yield was recorded in STCR-IPNS - 50 t ha-1 (50.6 t ha-1) recording an increase of 56.7 per cent over blanket recommendation and 69.0 per cent over farmer's practice. Among the treatments, STCR-IPNS-50 t ha-1 recorded relatively higher RR (81.3 kg kg-1) and BCR (2.24) than other treatments. Post-harvest soil available NPK indicated the build up and maintenance of soil fertility due to soil test based fertilizer recommendation under IPNS. [ABSTRACT FROM AUTHOR]

Field experiments were conducted on a Typic Haplustalf soil of Tamil Nadu by adopting the inductive cum targeted yield model, and fertilizer requirements were quantified for beetroot based on soil test and yield target. The basic parameters [nutrient requirement (NR) and contributions of nutrients from soil (Cs), fertilizer (Cf), and vermicompost (Cvermi)] were computed from the field experimental data. Using these basic parameters, we developed fertilizer prescription equations under the integrated plant nutrition system (IPNS), and nomograms were formulated for the desired yield target of beetroot for a range of soil test values. The quantity of fertilizers that could be contributed by vermicompost at 5 t ha-1 was evaluated as 40, 21, and 30 kg nitrogen (N), phosphorus pentoxide (P2O5), and potassium oxide (K2O), respectively, when applied along with the NPK fertilizers as per soil test and desired yield target. [ABSTRACT FROM AUTHOR]

An experiment was conducted on Vertic Ustropept following Ramamoorthy's Inductive cum targeted yield model to elucidate the relationship between soil test values and response of ashwagandha (Withania somnifera (L.) Dunal) to added fertilizers under Integrated Plant Nutrition System (IPNS). Nutrient requirement and contribution from soil, fertilizers and FYM were calculated. The percent contribution from soil, fertilizer and FYM were 19.03, 31.30 and 23.14 for N; 20.26, 17.30 and 6.38 for P2O5; 11.08, 62.53 and 30.39 for K2O. Fertilizer prescription equations were developed for ashwagandha and nomograms were formulated based on the equations for a range of soil test values and desired target yield under IPNS. Following IPNS practice (NPK+ FYM @12.5 t ha-1), 40, 24 and 30 kg ha-1 of fertilizer N, P2O5 and K2O respectively, could be saved. [ABSTRACT FROM AUTHOR]