the effects of salinity on extractability and chemical fractions of zinc in selected calcareous soils of iran

use of saline water for irrigation has shown considerable promise. however, its effect on the solubility and bioavailability of native soil nutrients is not well understood. this study was conducted to evaluate the effects of salinity on the behavior of zinc(zn) in calcareous soils. the soil samples with different physiochemical properties were collected from four locations in khorasan province (iran). the factorial experiment was carried out as a completely randomized design on soils with four levels of water salinity (0, 37.5, 75 and 150 mole m-3 prepared with the same equivalents of nacl and cacl2) and four reaction times (0, 10, 20, and 30 days) with three replications. dtpa-extractable zn was measured in the incubated soil samples after the given reaction times. different chemical forms of zn were characterized after 30 days using the sequential extraction procedure. dtpa-extractable zn increased by 1 to 6.3% with the increasing levels of salinity, and decreased from 8.7 to 3.9% by increasing the reaction time significantly (p