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Pak. J. Bot., 44(6): 1891-1896, 2012.

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IMPACTS OF RICE PLANT ROOTS ON THE VARIATION IN ELECTRO-PHYSICO-CHEMICAL PROPERTIES OF SOIL WATERS

MUHAMMAD FARRAKH NAWAZ^1,2*, GUILHEM BOURRIɳ, SADAF GUL⁴, FABIENNE TROLARD³, IRFAN AHMAD¹, M. AYYOUB TANVIR¹ AND JEAN-CLAUDE MOURET⁵

Abstract: Lowland rice crop is cultivated under continuous flooding and anaerobic conditions but rhizospheric region of the rice plants can have different physico-chemical conditions than in the absence of roots. However, it is very difficult to measure all physico-chemical parameters instantaneously in the rhizosphere because this region, being highly dynamic, altering rapidly those parameters of surrounding soil waters. Present study has compared the evolution of electro-physico-chemical properties (pH, redox potentials (pe), Electrical Conductivity (EC) and temperature) of soil waters during a complete day at two different phenological stages in the presence of rice roots (rhizosphere) and in the absence of roots to analyse the effect of rhizosphere on soil waters. In the rhizosphere, pH of soil waters was found comparatively low (<7) as compared to absence of roots (>7). Similarly, small EC values were observed in the rhizosphere. Great fluctuations (diurnal patterns) were observed during the complete days which were directly associated to atmospheric conditions (temperature and light) and rhizospheric activity, and these fluctuations were more during vegetative phase as compared to maturation stage of rice. It was also observed that incorporation of crop residues resulted in the more reductive conditions in the rice culture.

¹Department of Forestry, Range Management and Wildlife, University of Agriculture, Faisalabad, Pakistan.

²INRA-UR 1119 Géochimie des Sols et des Eaux, 13545 Aix en Provence, France.

³INRA, UMR 1114 Emmah, F_84911 Avignon, France

⁴Department of Botany, University of Karachi. Pakistan

⁵Institut National de la Recherche Agronomique, UMR Innovation, Montpellier, France.

*Corresponding author’s E-mail address: kf_uaf@yahoo.com