<div>Background: Fertilizers are one of the major inputs of agriculture to increase crop production. In India, fertilizer consumption had increased over a period of four decades. There is an increase in demand for food and this in turn increases the demand for fertilizers. The increase in food production is due to use of proper inputs like fertilizers, quality seeds and pesticides. The fertilizer consumption in India increased from 65.6 thousand metric tons in 1950-51 to 26,593.4 MT in 2017-18. However, the fertilizer use in India has many problems. Firstly, it is imbalanced in terms of NPK. Secondly, there is a wide variation in the amount of fertilizer in different state. 
 
Methods: Primary data were collected from two districts namely Thiruvannamalai and Thanjavur of Tamil Nadu. In each of the two districts, two representative blocks namely, Cheyyar, Kalasapakkam in Thiruvannamalai district and Thanjavur and Orrathanadu in Thanjavur district were taken for the study. In each district, 120 farmers (60 in each block) from the list of soil tested farmers were drawn at purposive farmers from households with different land sizes. In addition, 60 control (non-soil tested) farmers (30 in each block) were selected in each purposive farmer from households amongst general rice and groundnut growing cultivators. 
 
Result: Nearly three-fourths (72 per cent) of the farmers getting their soils tested in the present study belonged to the small (47 per cent) and medium (25 per cent) categories of landholdings. All farmers have to travel long distance for soil test incurring sizable transportation cost. Generally, in Thanjavur district, soil test farmers have been travelling long distance from their farm to Aduthurai, where the soil test laboratory is located at a distance of 50-60 kms. There is no soil test laboratory in Thiruvannamalai district, hence, the farmers have to travel to the neighbouring district of Trichirapalli. The soil tested farmers travel from Vembakkam and Mamandur to Thiruvannamalai where the laboratory is located and the average distance is about 80-100 km. Nearly half of the paddy farmers and nearly, two-thirds of the groundnut growers expressed the view that the soil test has an important role in increasing crop yield. Almost half of the paddy farmers and one-third of the groundnut farmers did not how to take a soil sample from their farm land, whereas, another half of paddy farmers and one-third of groundnut growers reported that they did not know whom to approach in this regard. These are the major reasons cited for non-participation in the soil test process.</div>

Status of Soil Testing and Fertilizer Recommendations by the Farmers of Tamil Nadu

Background: Boron plays a crucial role in cell wall construction in plants and also facilitates the transfer of carbohydrates, which are essential for various physiological processes. The objective was to measure element concentrations in soil, water extracts and plant tissues (Zea mays) using Azomethine-H and ICP-MS within a controlled microplate assay.&nbsp; 
 
Methods: A microscopic plate repeat test was used to analyze the concentration of boron in soil extracts and plant tissue ash from local Zea mays leaves, considering the global trend in environmental sustainability. Tests aimed to modify the azomethine-H microscopic approach to eliminate pH and chemical interferences in soil samples and plant tissues. Due to their ability to ensure sample repeatability and quality control, micro spectrophotometers are ideal for high-throughput analysis.&nbsp; 
 
Result: The microplate test has enhanced boron measurement in soil and plant tissue samples. Our improvements to the microplate B assay have resulted in more accurate boron measurements in these samples. Microplate B testing is effective and suitable analysis in modern research and laboratories, using 40 times less chemical reagent per sample than traditional spectrophotometry. Additionally, microplates enable simultaneous analysis and calibration of samples. The modified plate test significantly improves boron measurement in soil and plant tissue samples, using 40 times fewer reagents than traditional spectrophotometry. This method is cost-effective, ideal research, commercial analysis and making it a valuable tool for modern laboratories.

Using Microplates to Test Boron in Zea mays Leaf Plant and the Surrounding Soil

<div>Background: Ethiopia has used only DAP and urea, which supplies only N and P with a blanket application rate.&nbsp; 
 
Methods: This study recommended soil test-based fertilizer(s) for agricultural soils of three districts in the KambataTembaro zone of southern Ethiopia. Four hundred sixty geo-referenced composite soil samples were collected and analyzed. 
 
Result: The result revealed that N, P, K, S, B and Cu were deficient in the soils of the study area. Overlay analysis showed that 13 fertilizers could be recommended for the study area using possible element combinations. However, only NPSB and NPSBCu were found to be dominant by covering 89 and 11% after pooling other formulations, which span over less than 5% to more similar larger fertilizer types. Among soil samples collected,16% of soil samples were found at pH values &lt;5.5 and therefore required liming. The application of DAP and urea only can&rsquo;t afford optimum crop production in the study area. In addition to N and P, S, B and Cu were deficient in the study area. A further detailed study is recommended to determine the adequatelyblended fertilizers and liming rates.</div>

​​Soil Test based Fertilizer Recommendation for Selected Districts of Southern Ethiopia Agricultural Soils

<div>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.&nbsp; 
 
Methods: Field experiment was conducted in 2021 at the Tapioca and Castor Research station, Yethapur,&nbsp; region near Salem city, Tamil&nbsp; Nadu, India (11o35&rsquo;N, 78o29&rsquo;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.&nbsp; 
 
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).</div>

Soil test crop response based integrated plant nutrition system for hybrid castor on an Alfisol

Background: Green gram, also known as &ldquo;mungbean&rdquo; is rich in protein and vitamins. Either chemical fertilizers or organic manures alone may not suffice to meet the nutrient demand with sustenance of soil health. Hence, soil test based fertilizer prescription for green gram becomes need of the hour. 
&nbsp; 
Methods: Fertilizer prescription equations (FPEs) were developed for green gram grown under Integrated Plant Nutrition System (IPNS) on Typic Rhodustalf (Palaviduthi soil series) in Tamil Nadu. The developed FPEs were validated through four field experiments with Green gram variety CO 8 conducted during 2023 and 2024 in Dindigul district in the farmers holdings with ten treatments viz., Blanket (RDF alone), Blanket+FYM (RDF + FYM @ 12.5 t ha-1), STCR-NPK alone and STCR - IPNS for 8, 10 and 12 q ha-1, Farmer&rsquo;s Practice and Absolute control in non replicated manner. Growth, yield parameters and grain yield were recorded and soil fertility was assessed. 
&nbsp; 
Result: The highest growth and yield attributes were observed in the treatment receiving STCR-IPNS-12 q ha-1&nbsp;with an increase of 34.1 per cent over blanket recommendation and 58.08 per cent over Farmers Practice. The post-harvest soil available NPK indicated the build up and maintenance of soil fertility due to soil test based fertilizer recommendation under IPNS. Results highlighted that in all the four locations, the per cent achievement of the targeted yield was within &plusmn; 10 per cent deviation from the yield target proving the validity of the STCR-IPNS equations developed for recommending fertilizer doses for green gram.

Soil Test and Yield Target Based Balanced Fertilizer Prescription Model for Green Gram on Alfisols of Tamil Nadu

Background: Adoption of SSNM is directly affected by cost of fertilizer. Soil test crop response (STCR) concept attribute to contribution of soil and targeted yield level for fertilizer recommendation for a selected crop. This approach is also known as prescription based fertilizer recommendations. It is specific type of soil, climatic condition and specific location. Nutrient requirement is differ for different crops. The available soil nutrients efficient used and added to those available soil nutrients through fertilizers is different for different type of soil geography under a particular set of climatic conditions. 
 
Methods: A research experiment was carried out during rabi 2017-18, 2018-19 and 2019-20 at Research Farm of Agronomy, Dr. P.D.K.V, Akola (Maharashtra). Fertilizers were applied based on uptake pattern of crop, target yield levels and soil test values. The experiment was laid out in FRBD-Factorial randomized block design with two factors. Total 15 treatment combinations were formed which replication 4 times. 
 
Result: Significantly greater uptake of nitrogen (62.76, 74.67 and 81.89 kg ha-1), phosphorus (19.15, 24.32 and 29.38 kg ha-1), potassium (80.32, 92.14 and 99.18 kg ha-1), sulphur (18.46, 24.10 and 26.03 kg ha-1) and zinc (493.97, 571.01 and 620.91 g ha-1) recorded in treatment where crop supplied with farm yard manure @ 5 t ha-1 than rest of treatments during 2017-18, 2018-19 and 2019-20, respectively. A similar trend was observed in respect of soil nutrient status such as available N, P2O5, K2O, S and Zn. Application of fertilizers through soil test crop response equation with zinc sulphate @ 25 kg ha-1 and Sulphur @ 10 kg ha-1 registered maximum total uptake of nitrogen (66.89, 78.99 and 90.06 kg ha-1), phosphorus (20.78, 25.31 and 31.96 kg ha-1), potassium (86.05, 97.99 and 109.09 kg ha-1), sulphur (20.27, 26.39 and 29.80 kg ha-1) and zinc (537.78, 618.06 and 696.21 g ha-1) than rest of nutrient management treatments during three years of field experiment, respectively. The same trend was observed with respect to available N, P2O5, K2O, S and Zn under respective treatment during three years of experimentation.

Estimation of Nutrient Uptake and Available Nutrient Status of Rabi Safflower Through Soil Test Crop Response in Rainfed Ecosystem

Background: Soil test crop response (STCR) approach assists in determining the appropriate amount of fertilizer to use for particular season and location based on the initial soil fertility status and crop response in terms of nutrient uptake and yield. A field experiment was conducted during 2020-21 at Dharwad, by adopting the Inductive Cum Targeted Yield Model to develop soil test-based fertilizer prescriptions under STCR and STCR-IPNS approach to achieve desired target yields of maize in vertisols of Northern Karnataka, India.&nbsp; 
 
Methods: In the experiment&rsquo;s first phase, an exhaust crop fodder maize was grown in three different fertility strips. After the harvest of fodder maize, the soil fertility levels varied significantly among the strips, indicating the creation of fertility gradients. In the second phase of the experiment, a test crop (hybrid maize) was grown and the response of maize to four levels of N, P and K and three levels of FYM under different fertility gradients was studied. The basic parameters viz, nutrient requirement (NR), contribution of nutrients from soil (Cs), fertilizers (Cf) and FYM (Cfym) were computed using the data from test crop experiment. The basic parameters viz, nutrient requirement (NR), contribution of nutrients from soil (Cs), fertilizers (Cf) and FYM (Cfym) were computed using the data from test crop experiment.&nbsp; 
 
Result: Using the basic parameters, fertilizer prescription equations for desired yield targets of maize under NPK fertilizers alone and under STCR-IPNS (with FYM) were derived based on initial soil test values. Results of the validation experiment in kharif 2021 revealed that the grain yield was significantly higher under STCR-IPNS equation with a target yield of 100 q ha-1 as compared to other treatments. STCR-IPNS equation with the application of FYM to achieve 100 q ha-1 target yield resulted in savings of 11, 10 and 15 percent of N, P2O5 and K2O as compared to STCR-NPK alone equation.

Development of Soil Test Crop Response (Stcr) and Stcr-Integrated Plant Nutrition Supply (Ipns) Models to Achieve Targeted Yields of Maize (Zea mays L.) in Vertisols of Northern Karnataka

<div>Background: Soil test based application of plant nutrients helps to realize higher response ratio and benefit: cost ratio as the nutrients are applied in proportion to the magnitude of the deficiency of a particular nutrient and the correction of the nutrients imbalance in soil helps to harness the synergistic effects of balanced fertilization 
 
Methods: Soil test crop response correlation studies were conducted to formulate the fertilizer adjustment equations for soybean (Var. GS-3) under integrated plant nutrition system on medium black calcareous soils during year 2016 and 2017 in kharif season following Ramamoorthy&rsquo;s inductive-cum-targeted yield approach. 
 
Result: The nutrients requirement for producing one quintal of soybean was 5.65, 0.91 and 2.53 kg of N, P2O5 and K2O, respectively in presence of FYM (indicate dose). The per cent contributions from soil and fertilizer nutrients were found to be 35.03 and 74.5 for nitrogen, 55.13 and 27.6 for phosphorus and 10.36 and 51.6 per cent for potassium with FYM, Similarly, the per cent contribution of fertilizers was 65.25 for nitrogen, 22.49 for phosphorus and 43.89 for potassium without FYM. The per cent nutrient contribution of FYM was 28.27 for nitrogen, 4.97 for phosphorus and 10.48 for potassium.</div>

<div>Soil Test Based Fertilizers Application for Targeted Yield of Soybean (Glycin max L.) in Saurashtra Region of Gujarat</div>

Background: On-farm testing of fertilizer prescription equations is imperative to demonstrate the efficacy of technology implementation for the benefit of the stakeholders. The current research was conducted on a farmer&rsquo;s holding, using blackgram (Vigna mungo L. Hepper), to evaluate the fertiliser prescription equations (FPEs) in the Thondamuthur block of Coimbatore district, Western Zone of Tamil Nadu. The treatments included control, blanket, blanket + FYM, Soil Test Crop Response (STCR) based fertilizer dose for an yield target of 1.0, 1.2 and 1.4 t ha-1, STCR-IPNS based fertilizer dose for an yield target of 1.0, 1.2 and 1.4&nbsp; t ha-1 and farmer&rsquo;s practice. 
 
Methods: Using the data of yield and fertilizer doses applied, parameters viz., per cent achievement, response ratio (RR), benefit: Cost ratio (BCR) were computed.&nbsp; 
 
Result: STCR-IPNS with a targeted yield of 1.4 t ha-1 consistently displayed the most substantial growth, superior yield and yield-related characteristics, with the per cent achievement falling within &plusmn;10 per cent variation. Furthermore, it exhibited a higher response ratio (RR) and a more favourable Benefit Cost Ratio (BCR) when compared to both farmer&rsquo;s practice and blanket fertilizer recommendations. The results revealed that the target yield has been achieved within &plusmn;10 per cent variation proving the validity of the equations.

Enhancing Blackgram Yield: Validating a Soil Test-driven Fertilizer Prescription Equation for Alfisol

Background:Enhancing food security and nutrition for the expanding population is a significant concern. In this context, the application of inorganic fertilisers and organic manures and plays a pivotal role by supplying vital nutrients to plants. This practice elevates the nutrient content and overall nutritional quality of crops, thereby contributing substantially for meeting the nutritional requirements of a growing populace. Conversely, the repercussions of imbalanced nutrition are detrimental, leading to reduced agricultural productivity and soil fertility degradation. These factors, in turn, contribute to increased cultivation costs. Addressing this multifaceted issue necessitates a precise quantification of inorganic fertiliser integration with organic manures as an effective means of resolving these challenges.

Methods: The current research was conducted on a farmer&#39;s holding, using blackgram (variety: VBN 11) in Thondamuthur block of Coimbatore district, Western Zone of Tamil Nadu to study the effect of different N, P2O5, K2O and IPNS dosages in nutrient acquisition and quality parameters. The treatments included absolute control, blanket, blanket + FYM, Soil Test Crop Response (STCR) based fertiliser dose for an yield target of 1.0, 1.2 and 1.4 t ha-1, STCR-IPNS based fertiliser dose for an yield target of 1.0, 1.2 and 1.4&nbsp; t ha-1 and farmer&rsquo;s practice.

Result: The highest nutrient uptake and quality parameters were recorded when employing STCR-IPNS at a targeted yield of 1.4 t ha⁻1. This finding strongly underscores the value of incorporating these practices into our agricultural approach. Doing so not only paves the way for sustainable, nutrient-rich food production but also effectively addresses the issue of imbalanced nutrition. Moreover, it plays a vital role in enhancing soil health. In sum, this comprehensive approach is pivotal in fortifying food security and elevating nutritional standards.

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Effect of Integrated Plant Nutrient Management based on Soil Test Crop Response on Primary Plant Nutrients Uptake and Quality Parameters of Blackgram on Alfisols in Western Zone of Tamil Nadu, India