Relationship of Soil Properties with Yield and Morphological Parameters of Pistachio in Geomorphic Surfaces of Bajestan Playa, Northeastern Iran

Pistachio is one of the important and strategic crops in Iran. The objective of this study was to investigate the impact of soil properties on the yield and selected morphological properties of pistachio in Faizabad area, in northeastern Iran. For this purpose, in an area of 20,000 hectares, four geomorphic surfaces were recognized at the margin of Bajestan playa. In each geomorphic surface, three good, medium, and poor quality orchards were identified. A representative soil profile in each orchard was described and sampled. Yield, height, leaf nutrient elements, and morphological properties of three pistachio trees were measured in each orchard. The highest yield (24.5 kg tree-1) was observed in the good orchard in non-saline clay flat geomorphic surface and the lowest (5.2 kg tree-1) was observed in the poor orchard of alluvial fan-clay flat geomorphic surface. Morphological characteristics were in suitable conditions in the good orchard with non-saline clay flat geomorphic surface. The results of correlation and multivariate regression showed that soil salinity (EC), clay content, and soil boron concentration had a significant negative impact on the yield, morphological characteristics, and leaf nutrient elements.