Survey on Boron position on water, soil and pistachio in pistachio growing area in Iran

Boron (B) is an essential micro-nutrient for normal growth of plants. Toxicity of this nutrient occurs in arid and semi-arid areas because of high levels of its concentration in soil and irrigation waters. This study was conducted to determine the status of water, leaf and soil B concentration and compare its concentration in the main pistachio growing areas of Iran. Boron in three depth of soils (0-40, 40-80 and 80-120 cm) was determined using saturation and hot water extraction methods. Boron concentration was measured by a colorimetric procedure using the Azomethin-H reagent in soil, leaves extracts and irrigation water samples. The mean values for water B concentration in pistachio growing areas of Rafsanjan, Zarand, Sirjan, Kerman, Khorasan, Semnan, Ghazvin and Yazd were 4.2, 1.2, 2.5, 2, 1.8, 1.5, 2.5 and 3.1 mg L-1, respectively. A significant positive correlation was obtained between leaf B concentration and boron in two subsurface depths by saturation extraction method in Anar and Nough areas. The mean values for leaf B concentration in Rafsanjan, Zarand, Sirjan, Kerman, Khorasan, Semnan, Ghazvin and Yazd were 557, 213, 247, 212, 319, 179, 215 and 218 Mg gr-1 D.M, respectively. EC, clay and silt had a significant positive correlation with soil boron concentration (p،ـ0.01) whereas a negative significant correlation was observed for sand (p،ـ0.01). Results indicate that saturation extraction method should be used to evaluate soil B concentration in Anar and Nough areas. Water, soil and leaf boron concentration in Zarand, Sirjan, Kerman, Khorasan, Semnan, Ghazvin and Yazd areas was lower than pistachio growing areas of Rafsanjan. Relatively high leaf B concentration especially in Koshkouieh and suburbs suggest a suitable management is needed to sustainable pistachio production. Key words: Boron, Iran, Pistachio, Pistachio growing areas.