Critical Level of Magnesium for Cowpea [Vigna unguiculata (L.) Walp.] in Ultisols of Kerala

DOI: 10.18805/LR-4267    | Article Id: LR-4267 | Page : 1060-1065
Citation :- Critical Level of Magnesium for Cowpea [Vigna unguiculata (L.) Walp.] in Ultisols of Kerala.Legume Research.2021.(44):1060-1065
V.P. Soniya, P.S. Bhindhu, P. Sureshkumar soniyachandran95@gmail.com
Address : Radiotracer Laboratory, College of Horticulture, Vellanikkara, Thrissur-680 656, Kerala, India.
Submitted Date : 24-10-2019
Accepted Date : 8-01-2021


Background: Ultisols are characterized by low pH, low cation exchange capacity and low base saturation due to dominance of kaolinite and oxides and hydrous oxides of iron and aluminium. Among the basic cations, magnesium has smaller ionic size and larger hydrated radius which limits binding of Mg to soil exchange sites. As a result the deficiency of magnesium is a common nutritional disorder in these soils due to leaching of bases under humid tropical conditions. The determination of critical level of magnesium in soil and plant helps to manage the nutrient deficiency and will help to avoid crop loss.
Methods: A pot culture experiment was conducted to determine the critical level of magnesium for cowpea in Ultisols of Kerala during January 2019. Graded doses of magnesium were applied @ 5 mg kg-1 to 80 mg kg-1 of soil as magnesium carbonate along with recommended dose of fertilizers to evaluate the effect of applied magnesium on soil pH, available magnesium in soil, magnesium content in plant, crop uptake and yield.
Result: Soil pH and available magnesium in soil recorded at flowering and harvest was highest where magnesium was applied @ 80 mg kg-1 of soil. Magnesium content in stem and leaves was found to increase with the levels of magnesium added. No significant variation in the content of magnesium in pods was recorded. Crop uptake (66.62 mg g-1) of magnesium and yield per plant (79.33 g plant-1) was highest in the treatment (T5) where magnesium was applied @ 10 mg kg-1 of soil. The critical level of magnesium determined by Cate and Nelson graphical method was found to be 75 mg kg-1 of available magnesium in soil and 0.38% in leaves of cowpea during flowering.


Cowpea Critical level Magnesium Ultisols


  1. Cate, R.B. and Nelson, L.A. (1965). A rapid method for correlation of soil test analysis with plant response data. International soil testing series Technical. Bull.No.1. North Carolina State University, Agricultural Experiment Station, Releigh. 420p.
  2. Cakmak, I. and Yazici, A.M. (2010). Magnesium- a forgotten element in crop production. Better Crops. 94: 23-25.
  3. Cakmak. I and Kirby, E.A. (2008). Role of magnesium in carbon partitioning and alleviating photo oxidative damage. Physiol. Plant. 133: 692-704.
  4. Canizella, B.T., Moreira, A., Moraes, L.A.C. and Fageria, N.K. (2017). Response of common bean varieties to the magnesium application in the tropical soil. J. Plant Nutr. 40(2): 207-218.
  5. Fageria, N.K., De Souza, C.M.R. (1991). Upland rice, common bean and cowpea response to magnesium application on an Oxisol. Commun. Soil Sci. Plant Anal. 22: 17-18.
  6. Fageria, N.K. (2009). The Use of Nutrients in Crop Plants. CRC Press, Taylor and Francis Group, London, 430p.
  7. Karley, A.J. and White, P.J. (2009). Moving cationic minerals to edible tissues: potassium, magnesium, calcium. Curr. Opin. Plant Biol. 12: 291-298.
  8. Kasinath, B.L., Ganeshmurthy, N.S. and Nagegowda, N.S. (2014). Critical limit of soil and plant magnesium in tomato-growing soils of South Karnataka. J. Hortic. Sci. 9: 209-212.
  9. Mengutay, M., Ceylan, Y., Kutman, U.B. and Cakmak, I. (2013). Adequate magnesium nutrition mitigates adverse effects of heat stress on maize and wheat. Plant Soil 368: 57-72.
  10. Mayland, H.F. and Wilkinson, S.R. (1989). Soil factors affecting magnesium availability in plant-animal systems: AReview. J. Anim. Sci. 67: 3437-3444.
  11. Roy, R.N., Fink, A., Blair, G.J. and Tandon, H.L.S. (2006). Plant nutrition for food security: A guide for integrated nutrient management. FAO Fertilizer and Plant Nutrient Bulletin.16, 348p.
  12. Sureshkumar, P., Geetha, P. and Bhindhu, P.S. (2018). Chemistry and Fertility - Management of Humid Tropical Soils of Kerala as Influenced by Topography and Climate. Indian J. Fertil. 14(3): 30-44.
  13. White, P.J. and Brown, P.H. (2010). Plant nutrition for sustainable development and global health. Ann. Bot. 105(7): 1073-1080.

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