the effects of sodium chloride and zn rates and sources on the growth and chemical composition of lowland rice (oryza sativa l.) were studied using calcareous soil in a greenhouse experiment. the treatments comprised 5 levels of nacl (0, 12.5, 25, 37.5 and 50 mmol kg-1 soil), three zn rates (0, 5 and 10 mg kg-1 soil) and two zn sources (znso4, 2h2o and znedta). applied salinity decreased shoot ...