PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

This study reviews the progress and challenges in developing rapid colorimetric and turbidimetric test kits for commercial soil nutrient analyses, focusing on nitrogen, phosphorus, and potassium. Although common laboratory analytical techniques are accurate, they are often expensive and require advanced technical skills. Consequently, commercial in situ soil test kits have gained attention as potential alternatives to these tests. These kits use universal extractants that can simultaneously extract multiple nutrients and colorimetry and turbidimetry for nutrient determination. A critical aspect of these kits is the selection of suitable extractants that are effective under various soil conditions, chemically safe, compatible with analytical systems, and have a long shelf life. This review assesses the efficacy of several extractants in conjunction with colorimetric and turbidimetric reagents. Examples include H3A-4 and Kelowna extractants using the zinc–Griess reagent, salicylic method, molybdenum yellow method, and sodium tetraphenyl boron method for nitrate, ammonium, phosphorus, and potassium, respectively. These extractants and reagents have been highlighted for their adaptability, safety, rapid color formation, and minimal compatibility issues, making them promising candidates for rapid test kit development. However, rapid soil test kits are designed to provide a general understanding of soil nutrient status. They are not intended to replace detailed laboratory analyses in situations where precision is critical. Additionally, these kits should be validated against standard laboratory methods to determine their accuracy and reliability. This review highlights the importance of balancing practicality and accuracy when developing rapid soil test kits for soil nutrient analysis.

• American Public Health Association, American Water Works Association, & Water Environment Federation. (n.d.). Standard methods for the examination of water and wastewater: 4500-NH3 (ammonia). APHA Press.

• Baethgen, W. E., & Alley, M. M. (1989). A manual colorimetric procedure for measuring ammonium nitrogen in soil and plant Kjeldahl digests. Communications in Soil Science and Plant Analysis, 20(9–10), 961–969. https://doi.org/10.1080/00103628909368129

• Berthelot, M. P. E. (1859). Berthelot’s reaction mechanism. Report de Chimie Applique.

• Bibiso, M., Taddesse, A. M., & Assefa, M. (2012). Evaluation of three universal extractants for the determination of P, NO3- and K in some soils of Ethiopia. Advances in Life Science and Technology, 6, 16–24.

• Bibiso, M., Taddesse, A. M., Gebrekidan, H., & Melese, A. (2015). Evaluation of universal extractants for determination of some macronutrients from soil. Communications in Soil Science and Plant Analysis, 46(19), 2425–2448. https://doi.org/10.1080/00103624.2015.1081925

• Bowden, M., Sequiera, M., Krog, J. P., Gravesen, P., & Diamond, D. (2002). Analysis of river water samples utilising a prototype industrial sensing system for phosphorus based on micro-system technology. Journal of Environmental Monitoring, 4(5), 767–771. https://doi.org/10.1039/b200330a

• Bünemann, E. K., Bongiorno, G., Bai, Z., Creamer, R. E., Deyn, G. D., de Goede, R., Fleskens, L., Geissen, V., Kuyper, T. W., Mäder, P., Pulleman, M., Sukkel, W., van Groenigen, J. W., & Brussaard, L. (2018). Soil quality — A critical review. Soil Biology and Biochemistry, 120, 105–125. https://doi.org/10.1016/j.soilbio.2018.01.030

• Cataldo, D. A., Maroon, M., Schrader, L. E., & Youngs, V. L. (1975). Rapid colorimetric determination of nitrate in plant-tissue by nitration of salicylic-acid. Communications in Soil Science and Plant Analysis, 6(1), 71–80. https://doi.org/10.1080/00103627509366547

• Chitbankluai, K., Buranachai, C., Limbut, W., & Thavarungkul, P. (2021). Paper-based colorimetric sensor for potassium ion detection in urine by crown ether modified gold nanoparticles. Journal of Physics: Conference Series (Vol. 1719, No. 1, p. 012026). IOP Publishing. https://doi.org/10.1088/1742-6596/1719/1/012026

• Cogan, D., Cleary, J., Fay, C., Rickard, A., Jankowski, K., Phelan, T., Bowkett, M., & Diamond, D. (2014). The development of an autonomous sensing platform for the monitoring of ammonia in water using a simplified Berthelot method. Analytical Methods, 6(19), 7606–7614. https://doi.org/10.1039/C4AY01359J

• De Silva, C. S., Koralage, I. S. A., Weerasinghe, P., & Silva, N. R. N. (2015). The determination of available phosphorus in soil: A quick and simple method. OUSL Journal, 8, 1–7. https://doi.org/10.4038/ouslj.v8i0.7315

• Dimkpa, C., Bindraban, P., McLean, J. E., Gatere, L., Singh, U., & Hellums, D. (2017). Methods for rapid testing of plant and soil nutrients. In E. Lichtfouse (Ed.), Sustainable agriculture reviews (Vol. 25, pp. 1–43). Springer. https://doi.org/10.1007/978-3-319-58679-3_1

• Doane, T. A., & Horwáth, W. R. (2003). Spectrophotometric determination of nitrate with a single reagent. Analytical Letters, 36(12), 2713–2722. https://doi.org/10.1081/AL-120024647

• Faber, B. A., Downer, A. J., Holstege, D., & Mochizuki, M. J. (2007). Accuracy varies for commercially available soil test kits analyzing nitrate–nitrogen, phosphorus, potassium, and pH. HortTechnology, 17(3), 358-362. https://doi.org/10.21273/HORTTECH.17.3.358

• Food and Agriculture Organization of the United Nations. (2021a). Standard operating procedure for soil available phosphorus: Bray I and Bray II method. FAO. https://www.fao.org/3/cb3460en/cb3460en.pdf

• Food and Agriculture Organization of the United Nations. (2021b). Standard operating procedure for soil available phosphorus: Olsen method. FAO. https://www.fao.org/3/cb3644en/cb3644en.pdf

• Gelderman, R. H., & Beegle, D. (2011). Nitrate-nitrogen. In J. R. Brown (Ed.), Recommended chemical soil test procedures: For the north central region (pp. 17–20). Missouri Agricultural Experiment Station.

• Gilchrist, A., & Nobbs, J. (1999). Colorimetry, theory. In J. Lindon, J. Holmes, & G. Tranter (Eds.), Encyclopedia of spectroscopy and spectrometry (pp. 337–343). Academic Press. https://doi.org/10.1006/rwsp.2000.0044

• Gough, N. (1996). Soil and plant tissue testing method and interpretations of their results for Bristish Columbia agricultural soils. https://www2.gov.bc.ca/assets/gov/farming-natural-resources-and-industry/agriculture-and-seafood/agricultural-land-and-environment/soil-nutrients/600-series/634200-3_soil_and_plant_tissue_testing_methods.pdf

• Hachiya, T., & Sakakibara, H. (2016). Interactions between nitrate and ammonium in their uptake, allocation, assimilation, and signaling in plants. Journal of Experimental Botany, 68(10), 2501–2512. https://doi.org/10.1093/jxb/erw449

• Haney, R. L., Haney, E. B., Harmel, R. D., Smith, D. R., & White, M. J. (2016). Evaluation of H3A for determination of plant available P vs. FeAlO strips. Open Journal of Soil Science, 6(11), 175–187. https://doi.org/10.4236/ojss.2016.611017

• Haney, R. L., Haney, E. B., Hossner, L. R., & Arnold, J. G. (2006). Development of a new soil extractant for simultaneous phosphorus, ammonium, and nitrate analysis. Communications in Soil Science and Plant Analysis, 37(11–12), 1511–1523. https://doi.org/10.1080/00103620600709977

• Haney, R. L., Haney, E. B., Hossner, L. R., & Arnold, J. G. (2010). Modifications to the new soil extractant H3A-1: A multinutrient extractant. Communications in Soil Science and Plant Analysis, 41(12), 1513–1523. https://doi.org/10.1080/00103624.2010.482173

• Haney, R. L., Haney, E. B., Smith, D. R., & White, M. J. (2017). Removal of lithium citrate from H3A for determination of plant available P. Open Journal of Soil Science, 7(11), 301–314. https://doi.org/10.4236/ojss.2017.711022

• Heines, S. V. (1958). Peter Griess — Discoverer of diazo compounds. Journal of Chemical Education, 35(4), 187. https://doi.org/10.1021/ed035p187

• Horneck, D. A., Sullivan, D. M., Owen, J., & Hart, J. M. (n.d.). Soil test interpretation guide. Oregon State University Extension Service. https://extension.oregonstate.edu/sites/default/files/catalog/auto/EC1478.pdf

• International Organization for Standardization. (2020). General methods of test for pigments — Part 19: Determination of water-soluble nitrates (salicylic acid method). ISO. https://www.iso.org/obp/ui/en/#iso:std:iso:787:-19:ed-2:v1:en

• James Cook University. (2020). State of the tropics 2020 report. JCU. https://www.jcu.edu.au/__data/assets/pdf_file/0004/1271956/State-of-the-Tropics-2020-Summary.pdf

• Jeong, H., Park, J., & Kim, H. (2013). Determination of NH4+ in environmental water with interfering substances using the modified Nessler method. Journal of Chemistry, 2013, 359217. https://doi.org/10.1155/2013/359217

• Jones Jr., J. B. (1990). Universal soil extractants: Their composition and use. Communications in Soil Science and Plant Analysis, 21(13–16), 1091–1101. https://doi.org/10.1080/00103629009368292

• Kaylor, W. H. (1971). Determination of the phosphate in solid waste using the vanadomolybdophosphoric acid method. U.S. Environmental Protection Agency.

• Kim, H.-J. (2006). Ion-selective electrodes for simultaneous real-time analysis for soil macronutrients [Doctoral dissertation, University of Missouri-Columbia]. MOspace. https://mospace.umsystem.edu/xmlui/bitstream/handle/10355/4471/research.pdf?sequence=3

• Kumawat, C., Yadav, B., Verma, A. K., Meena, R. K., Pawar, R., Kharia, S. K., Yadav, R. K., Bajiya, R., Pawar, A., Sunil, B. H., & Trivedi, V. (2017). Recent Developments in multi-nutrient extractants used in soil analysis. International Journal of Current Microbiology and Applied Sciences, 6(5), 2578–2584. https://doi.org/10.20546/ijcmas.2017.605.290

• Le, P. T. T., & Boyd, C. E. (2012). Comparison of phenate and salicylate methods for determination of total ammonia nitrogen in freshwater and saline water. Journal of the World Aquaculture Society, 43(6), 885–889. https://doi.org/10.1111/j.1749-7345.2012.00616.x

• Li, L., Zhang, J., Xing, W., Chen, W., Wu, X., & Zhu, K. (2006). Development and validation of a new soil universal extractant: 0.02 molar strontium chloride. Communications in Soil Science and Plant Analysis, 37(11–12), 1627–1638. https://doi.org/10.1080/00103620600710249

• Liu, N., Wei, Z., & Wei, H. (2021). Colorimetric detection of nitrogen, phosphorus, and potassium contents and integration into field irrigation decision technology. IOP Conference Series: Earth and Environmental Science (Vol. 651, No. 4, p. 042044). IOP Publishing. https://doi.org/10.1088/1755-1315/651/4/042044

• López Pasquali, C. E., Fernández Hernando, P., & Durand Alegría, J. S. (2007). Spectrophotometric simultaneous determination of nitrite, nitrate and ammonium in soils by flow injection analysis. Analytica Chimica Acta, 600(1–2), 177–182. https://doi.org/10.1016/j.aca.2007.03.015

• López Pasquali, C. E., Gallego-Picó, A., Fernández Hernando, P., Velasco, M., & Durand Alegría, J. S. (2010). Two rapid and sensitive automated methods for the determination of nitrite and nitrate in soil samples. Microchemical Journal, 94(1), 79–82. https://doi.org/10.1016/j.microc.2009.09.005

• Ma, L., Duan, T., & Hu, J. (2020). Application of a universal soil extractant for determining the available NPK: A case study of crop planting zones in central China. Science of The Total Environment, 704, 135253. https://doi.org/10.1016/j.scitotenv.2019.135253

• Manatthammakul, W., Chittamart, N., Tawornpruek, S., & Aramrak, S. (2023). Correlation of soil available potassium rapidly analyzed by ion selective electrode and extracted by soil potassium extractants. Khon Kaen Agriculture Journal, 51(4), 634–647. https://doi.org/10.14456/kaj.2023.48

• Masjkur, M. (2009). Correlation between soil test phosphorus of kaolinitic and smectitic soils with phosphorus uptake of lowland rice. Journal of Tropical Soils, 14(3), 205–209. https://doi.org/10.5400/jts.2009.v14i3.205-209

• McIntosh, J. L. (1969). Bray and Morgan soil extractants modified for testing acid soils from different parent materials. Agronomy Journal, 61(2), 259–265. https://doi.org/10.2134/agronj1969.00021962006100020025x

• Merino, L. (2009). Development and validation of a method for determination of residual nitrite/nitrate in foodstuffs and water after zinc reduction. Food Analytical Methods, 2, 212–220. https://doi.org/10.1007/s12161-008-9052-1

• Morgan, M. P. (1941). Chemical soil diagnosis by the universal soil testing system (a revision of Bulletin 392). Connecticut Experiment Station. https://portal.ct.gov/-/media/caes/documents/publications/bulletins/b450pdf.pdf?la=en

• Morris, V. H., & Gerdel, R. W. (1933). Rapid colorimetric determination of potassium in plant tissues. Plant Physiology, 8(2), 315–319. https://doi.org/10.1104/pp.8.2.315

• Murphy, J., & Riley, J. P. (1962). A modified single solution method for the determination of phosphate in natural waters. Analytica Chimica Acta, 27, 31–36. https://doi.org/10.1016/S0003-2670(00)88444-5

• Murray, E., Nesterenko, E. P., McCaul, M., Morrin, A., Diamond, D., & Moore, B. (2017). A colorimetric method for use within portable test kits for nitrate determination in various water matrices. Analytical Methods, 9(4), 680–687. https://doi.org/10.1039/C6AY03190K

• Nagul, E. A., McKelvie, I. D., Worsfold, P., & Kolev, S. D. (2015). The molybdenum blue reaction for the determination of orthophosphate revisited: Opening the black box. Analytica Chimica Acta, 890, 60–82. https://doi.org/10.1016/j.aca.2015.07.030

• Neßler, J. (1856). Über das verhalten des jodquecksilbers und der quecksilberverbindungen überhaupt zu ammoniak und über eine neue reaction auf ammoniak [On the behaviour of iodine mercury and mercury compounds in general to ammonia and on a new reaction to ammonia]. Poppen.

• Nxumalo, N. L., Madikizela, L. M., Kruger, H. G., Onwubu, S. C., & Mdluli, P. S. (2020). Development of a paper-based microfluidic device for the quantification of ammonia in industrial wastewater. Water SA, 46(3), 506–513. https://doi.org/10.17159/wsa/2020.v46.i3.8661

• Pansu, M., & Gautheyrou, J. (2006). Handbook of soil analysis: Mineralogical, organic and inorganic methods. Springer. https://doi.org/10.1007/978-3-540-31211-6

• Paul, A. D., & Gibson Jr., J. A. (1959). Qualitative test for potassium using sodium tetraphenylboron. Journal of Chemical Education, 36(8), 380. https://doi.org/10.1021/ed036p380

• Qiu, J., Zhang, Y., Dong, C., Huang, Y., Sun, L., Ruan, H., Wang, H., Li, X., & Wu, A. (2019). Rapid colorimetric detection of potassium ions based on crown ether modified Au NPs sensor. Sensors and Actuators B: Chemical, 281, 783–788. https://doi.org/10.1016/j.snb.2018.10.139

• Ritchie, H. (2021). Excess fertilizer use: Which countries cause environmental damage by overapplying fertilizers? Our World in Data. https://ourworldindata.org/excess-fertilizer

• Roobroeck, D., Van Asten, P. J. A., Jama, B., Harawa, R., & Vanlauwe, B. (2016). Integrated soil fertility management: Contributions of framework and practices to climate-smart agriculture. https://www.researchgate.net/publication/289962704_Integrated_Soil_Fertility_Management_Contributions_of_framework_and_practices_to_Climate-Smart_Agriculture?channel=doi&linkId=5693ad8808aeab58a9a29f3d&showFulltext=true

• Sahrawat, K. L. (1979). Evaluation of some chemical extractants for determination of exchangeable ammonium in tropical rice soils. Communications in Soil Science and Plant Analysis, 10(7), 1005–1013. https://doi.org/10.1080/00103627909366957

• Sahrawat, K. L., & Prasad, R. (1975). A rapid method for determination of nitrate, nitrite, and ammoniacal nitrogen in soils. Plant and Soil, 42, 305–308. https://doi.org/10.1007/BF02186992

• Sarker, A., Kashem, M. A., Osman, K. T., Hossain, I., & Ahmed, F. (2014). Evaluation of available phosphorus by soil test methods in an acidic soil incubated with different levels of lime and phosphorus. Open Journal of Soil Science, 4(3), 103–108. https://doi.org/10.4236/ojss.2014.43014

• Schuffelen, A. C., Muller, A., & Van Schouwenburg, J. C. (1961). Quick-tests for soil and plant analysis used by small laboratories. Netherlands Journal of Agricultural Science, 9(1), 2–16. https://doi.org/10.18174/njas.v9i1.17630

• Simard, R. R., & Deschênes, M. (1992). Strontium chloride‐citric acid extraction procedure for agricultural and environmental purposes. Communications in Soil Science and Plant Analysis, 23(17–20), 2207-2223. https://doi.org/10.1080/00103629209368735

• Simard, R. R., & Zizka, J. (1994). Evaluating plant available potassium with strontium citrate. Communications in Soil Science and Plant Analysis, 25(9–10), 1779–1789. https://doi.org/10.1080/00103629409369152

• Simard, R. R., Zizka, J., & Tran, T. S. (1991). Strontium chloride-citric acid extraction evaluated as a soil-testing procedure for phosphorus. Soil Science Society of America Journal, 55(2), 414–421. https://doi.org/10.2136/sssaj1991.03615995005500020021x

• Soltanpour, P. N., & Schwab, A. P. (1977). A new soil test for simultaneous extraction of macro‐ and micro‐nutrients in alkaline soils. Communications in Soil Science and Plant Analysis, 8(3), 195–207. https://doi.org/10.1080/00103627709366714

• Ståhlberg, S. (1979). A simple turbidimetric method for determination of exchangeable soil potassium. Communications in Soil Science and Plant Analysis, 10(10), 1345–1353. https://doi.org/10.1080/00103627909366988

• Sukaton, A. R., Siswoyo, S., & Piluharto, B. (2017). Optimisation of extractant and extraction time on portable extractor potentiometric method for determining phosphate in soil. https://jurnal.unej.ac.id/index.php/prosiding/article/view/5255/4009

• van Lierop, W. (1986). Sol nitrate determination using the kelowna multiple element extractant. Communications in Soil Science and Plant Analysis, 17(12), 1311–1329. https://doi.org/10.1080/00103628609367792

• van Lierop, W. (1988). Determination of available phosphorus in acid and calcareous soils with the kelowna multiple-element extractant. Soil Science, 146(4), 284-291. https://doi.org/10.1097/00010694-198810000-00009

• van Lierop, W., & Gough, N. A. (1989). Extraction of potassium and sodium from acid and calcareous soils with the kelowna multiple element extractant. Canadian Journal of Soil Science, 69(2), 235–242. https://doi.org/10.4141/cjss89-024

• Vance, C. P., Uhde-Stone, C., & Allan, D. L. (2003). Phosphorus acquisition and use: Critical adaptations by plants for securing a nonrenewable resource. New Phytologist, 157(3), 423–447. https://doi.org/10.1046/j.1469-8137.2003.00695.x

• Vendrell, P. F., & Zupancic, J. (1990). Determination of soil nitrate by transnitration of salicylic acid. Communications in Soil Science and Plant Analysis, 21(13-16), 1705–1713. https://doi.org/10.1080/00103629009368334

• Waghwani, B., Balpande, S., & Kalambe, J. (2019). Development of microfluidic paper based analytical device for detection of phosphate in water. International Journal of Innovative Technology and Exploring Engineering, 8(6S), 592-595.

• Wang, S., Lin, K., Chen, N., Yuan, D., & Ma, J. (2016). Automated determination of nitrate plus nitrite in aqueous samples with flow injection analysis using vanadium (III) chloride as reductant. Talanta, 146, 744–748. https://doi.org/10.1016/j.talanta.2015.06.031

• Wang, Y., & Wu, W.-H. (2013). Potassium transport and signaling in higher plants. Annual Review of Plant Biology, 64, 451–476. https://doi.org/10.1146/annurev-arplant-050312-120153

• Whittles, C. L., & Little, R. C. (1950). A colorimetric method for the determination of potassium and its application to the analysis of soil extracts. Journal of the Science of Food and Agriculture, 1(11), 323–326. https://doi.org/10.1002/jsfa.2740011103