an orchard experiment was conducted at gonabad pistachio production station., khorasan, iran (1998-2003). in some pistachio trees, especially in cv. owhadi, leaf marginal chlorosis was already observed. then, gradual drying of leaves extended to the leaves' centers up to midsummer. with respect to salinity problems, some researches were done. two orchards of pistachio known as no.6 and no....