Exploring the dynamics of physico-chemical properties of soil waters in the rhizosphere of rice plants

International audience; Rice cultivation under submerged conditions results in a very dynamic system and quick changes in physico-chemical properties can be observed. It is very important to examine the short term dynamics of physico-chemical properties of soil waters at different phenological stages to understand the long term changes in rice culture system. The objective of this study was to observe the possible relation between plant physiological activities and physico-chemical properties in the soil waters at various phenological stages of rice. Samples of surface water layers (LS) and soil solutions (SS) from rice field were collected with modified and improved methods to determine the non-stable parameters (pH, electrical conductivity (EC), temperature and redox potentials), concentrations of major elements, alkalinity and dissolve organic carbon (DOC). Sampling was carried out during a complete day at two different phenological stages. It was observed that rhizospheric activity under the influence of atmospheric conditions (temperatures and light intensity) produced the diurnal patterns of various physico-chemical parameters in SS due to sudden absorption of some elements during particular hours. These diurnal patterns were more visible at vegetative stage as compared to reproductive stage. Furthermore, it was noticed that continuous absorption during the vegetative stage resulted in lower concentrations of major cations and anions in SS at reproductive stage. A strong correlation (R-2 value above 90) was observed among EC and major cations and anions.