Uptake of cadmium by rice crop in sewage irrigated soil

摘要

The results of green house experiment indicated that the yield of root, shoot and total dry matter of rice increased from 0.18 to 0.23 g pot~(-1), from 1.49 to 1.87 g pot~(-1) and from 1.67 to 2.09 g pot~(-1) respectively with increasing levels of Cd-FA (fulvic acid). The dry matter yields, concentrations and uptake of Cd by rice were significantly and positively correlated with organic carbon and DTPA-extractable Cd in soil. Root density and root length of rice exhibited positive and significant correlation with organic carbon, CEC, EC and negative correlation with clay content of the soil. On the other hand, root radius and half distance between roots showed significant and negative correlation with these parameters. DTPA-extractable Cd increasedwith increasing levels of Cd-FA application in soils. A regression model developed was found to predict the uptake of Cd on the basis of root parameters (root radius, root length, root density, half distance between roots) and diffusion coefficient of Cdin soils with almost 95 % level of confidence.