Abstract

In this study, experiment with four levels of nutrient solution pH control upper limit was conducted to explore the optimal nutrient solution pH management scheme under hydroponics by evaluating the nutrient solution characters i.e., pH, Electric Conductivity (EC), nitrate, soluble phosphorus (soluble-P), water spinach growth and quality. The results showed that the nutrient solution pH was 8.2 and unsuitable for water spinach growth under the treatment with no pH regulation during the experimental period. The pH could be maintained within a reasonable range for water spinach growth by adding nitric acid to nutrient solution. Meanwhile, the availability of cations and soluble-P were improved. The water/nutrition uptake was also promoted. Through nutrient solution pH control, the plant height, leaf number and fresh/dry shoot weight increased by 34.66-55.70%, 12.42-13.66%, 39.18

Keywords:

Hydroponics, nutrient solution, pH control upper limit, quality, water spinach, yield,

References

1. Bradley, P. and C. Marulanda, 2000. Simpli?ed hydroponics to reduce global hunger. Acta Hortic., 554: 289-295.
   Direct Link
2. Caruso, G., G. Villari, G. Melchionna and S. Conti, 2011. Effects of cultural cycles and nutrient solutions on plant growth, yield and fruit quality of alpine strawberry (Fragaria vesca L.) grown in hydroponics. Sci. Hortic-Amsterdam, 129(3): 479-485.
   CrossRef    Direct Link
3. Du, S., C. Jin and Y. Zhang, 2010. Current situations and research progress of nitrate pollution in vegetables and their regulating strategies. Sci. Agric. Sin., 43(17): 3580-3589. (In Chinese)
   Direct Link
4. Ko, M.T., T.I. Ahn, Y.Y. Cho and J.E. Son, 2013. Uptake of nutrients and water by paprika (Capsicum annuum L.) as affected by renewal period of recycled nutrient solution in closed soilless culture. Hortic. Environ. Biotechnol., 54(5): 412-421.
   CrossRef    Direct Link
5. Meric, M.K., I.H. Tuzel, Y. Tuzel and G.B. Oztekin, 2011. Effects of nutrition systems and irrigation programs on tomato in soilless culture. Agr. Water Manage., 99(1): 19-25.
   CrossRef    Direct Link
6. Morales, I. and M. Urrestarazu, 2013. Effect of a passive mixing device on the electrical conductivity and ph values of a nutrient solution. J. Irrig. Drain. E-ACSE, 140(4): 1-4.
   Direct Link
7. Pardossi, A., F. Malorgio, L. Incrocci, C.A. Campiotti and F. Tognoni, 2002. A comparison between two methods to control nutrient delivery to greenhouse melons grown in recirculating nutrient solution culture. Sci. Hortic-Amsterdam, 92(2): 89-95.
   CrossRef    Direct Link
8. Savvas, D. and K. Adamidis, 1999. Automated management of nutrient solutions based on target electrical conductivity, pH and nutrient concentration ratios. J. Plant Nutr., 22(9): 1415-1432.
   CrossRef    Direct Link
9. Sheikh, B.A., 2006. Hydroponics: Key to sustain agriculture in water stressed and urban environment. Pak. J. Agric. Agril. Eng. Vet. Sci., 22(2): 53-57.
   Direct Link
10. Spinu, V.C., R.W. Langhans and L.D. Albright, 1997. Electrochemical pH control in hydroponic systems. II Modell. Plant Growth Environ. Control Farm Manage. Protect. Cultivat., 456: 275-282.
    Direct Link
11. Webb, M.J., 1993. A multichannel pH controller for solution culture systems. Plant Soil, 155(1): 501-504.
    CrossRef    Direct Link
12. Yang, Q.C., L.L. Wei, W.K. Liu and R.F. Chen, 2012. Plant Factories: System and Practice. Chemical Industry Press, Beijing, pp: 18-38. (In Chinese)
    Direct Link
13. Zhao, S. and B. Li, 2001. Introduction to present status, development and new techniques of nutri-culture systems in Japan. T. CSAE, 17(4): 171-173. (In Chinese)
    

Competing interests

The authors have no competing interests.

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