Department of Controlled Agriculture, Kangwon National University1
Department of Horticulture, University of Sahmyook2
This experiment was performed to develop a model for nutrition ion concentration and EC in regard to change in pH from 4.0 to 8.0 in nutrient solution. The pH changes according to the variation of HPO4-2 and H2PO4- in the nutrient solution while variation of EC increased from pH 4.0 to 5.0, stabilized from pH 5.0 to 7.0 and increased again from pH 7.0 to 8.0. For the variance of major elements in the nutrient solution, K, Ca, N and P increased while pH was higher, especially the variables for K and P were increased largely. On the other hand, variables of Mg and S were stable. Based on analysis of the ion balance model of nutrient solution, the cation increased than anion over rising the variation of pH while balance point of ion moved from a-side to d-side. In addition, the imbalance increased while it moved away from the EC centerline as variance of pH increased. It was larger than effect of EC variance to correction values of equivalence ratios of K and Ca about variation of HPO4-2 and H2PO4- while as variance of pH increased, K decreased but Ca increased. These showed the result that variance of pH about correction values of equivalence ratios of K and Ca gave a second-degree polynomial model rating of 0.97. Through this research, it was identified the pH variable model about variance among pH, ion and EC according to gradient of phosphate.
1. Ahn, T.I., J.W. Shin, and J.E. Son. 2010. Analysis of changes in ion concentration with time and drainage ratio under EC-based nutrient control in closed-loop soilless culture for sweet pepper plants (Capsicum annuum L. ‘Boogie’). J. Bio-Environ. Cont. 19:298-304.
2. De Rijck G. and E. Schrevens. 1997. pH Influenced by the elemental composition of nutrient solutions. J. Plant Nutr. 20:911-923.
3. De Rijck G. and E. Schrevens. 1998. Cationic speciation in nutrient solutions as a function of pH. J. Plant Nutr. 21:861-870.
4. De Rijck G. and E. Schrevens. 1999. Anion speciation in nutrient solutions as a function of pH. J. Plant Nutr. 22:269-279.
5. Dyśko, J., S. Kaniszewski, and W. Kowalczyk. 2008. The Effect of nutrient solution pH on phosphorus availability in soilless culture of tomato. J. Elementology 13:189-198.
6. Masuda, M., T. Takiguchi, and S. Matsubara. 1989. Yield and quality of tomato fruits, and changes of mineral concentration in different strengths of nutrient solution. J. Jpn. Soc. Hortic.Sci. 58:641-648.
7. Robinson, R.A. and R.H. Stokes. 1959. Electrolyte solutions. Courier Dover Publications, London.
8. Rush, J.B. 2005. Hydroponics - A practical guide for the soilless grower. CRC press. p. 63-115.
9. Soh J.W. and Y.B. Lee. 2012. Estimated EC by the total amount of equivalent ion and ion balance model. Korean J. Hortic. Sci. Technol. 30:694-699.
10. Soh, J.W., K.S. Han, S.C. Lee, J.S. Lee, O.D. Kwon, and Y.B. Lee. 2012. Design of model of ion and electric conductivity. J. Bio-Environ. Cont. (Suppl. 2):133-134. (Abstr.)
11. Steiner, A.A. 1961. A universal method for preparing nutrient solutions of certain desired compositions. Plant Soil 15:134-154.
12. Steiner, A.A. 1980. The selective capacity of plants for ions and its importance for the composition and treatment of the nutrient solution. Acta Hortic. 98:87-97.
13. Steiner, A.A. 1984. The universal nutrient solution, Proceedings of IWOSC 1984 6th International Congress on Soilless Culture. p. 633-650.
14. Tanji, K.K. 1960. Predicting specific conductance from electrolytic properties and ion association in some aqueous solution. Soil Sci. Soc. Am. Proc. 33:887-889.
15. Trejo-Téllez, L.I. and F.C. Gómez-Merino. 2012. Nutrient solutions for hydroponic systems, p. 1-22. In: Toshiki A. (ed). Hydroponics - A standard methodology for plant biological researches. InTech, Janeza Trdine 9, 51000 Rijeka, Croatia.