ASHS 2025 Conference

Most of the world's pistachios are grown in saline-sodic soils with soil boron (B) levels over the 2 ppm suggested for most trees. As a resulting symmetrical leaf edge necrosis produced by B accumulation, “B toxicity”, is common and regarded as damaging to leaf photosynthetic capacity. This study was carried out in a 8-year-old pistachio orchard with field-budded Pistacia vera cv. ‘Golden Hills’ on cloned P. atlantica x P. integerrima, UCBI rootstocks, spaced at 18 x 20 feet, 121 trees per acre. The soil was a silty clay loam saline-sodic Cerrini complex with salinity ranging from 3 to 15dS/m, pH 7.5 to 8.2, boron levels of 3 to 12 ppm and soil sodium levels ranging from 16 to 130 meq/l (370 to 3000 ppm). High soil and water B levels will produce increasingly higher scion leaflet B leaf symptoms ranging from a slender marginal necrosis to almost complete necrosis. We analyzed the relationships among soil B, leaf B, percentage of damaged leaf surface and marketable yield. Our results a demonstrated a strong negative correlation of yield as a function of soil B. As soil B levels increased yield decreased; r = - 0.705, p < 0.001. However, both leaf B levels and % leaf damage had had weak, insignificant relationships with soil B levels. As soil B increased leaf B levels and the percentage of damaged leaf areas did not increase. However, there was a moderately positive relationship between leaf boron levels and leaf damage; r = 0.50, P