Effects of leaf nutrient contents on photosynthetic indices in Olives tree

The development of olive cultivation needs detailed studies to achieve the maximum yield and product quality by applying management plans including nutrition. In this research, the interactions of gas exchange and photosynthetic parameters were investigated with leaf nutrients contents of olive trees (cv. ‘Arbequina’) in super high density (SHD) cultivation under saline and calcareous soils condition in Tarom Sofla, Zanjan, Iran. The nutritional disorders and their effects on photosynthetic indices were revealed using the compositional nutrient diagnosis (CND) index micronutrients and macronutrients status. Finally, principal component analysis (PCA) was used to determine, the effects of all parameters on yield. The results showed that photosynthetic parameters had a significant positive correlation with nutrients such as zinc, phosphorus, and copper. Photosynthesis, transpiration, and stomatal conductance had highly correlated with yield of olive trees, which are important factors in increasing yields. The final CNDr2 index showed nutritional disorders in most orchards in the low yielding group. The average order of nutrient requirement is Ca> Mg> N> P> K in macronutrients and Zn> B> Mn> Cu in micronutrients in the group of low yielding orchards. The principal component analysis showed that highest yield of olive trees had a higher positive correlation than other orchards with P and K in macronutrients and Zn, and Cu in micronutrients; this increased the rate of photosynthesis and yield. PCA also showed the hidden effects of Ca and Mn deficiency on the reduction of photosynthetic parameters and yield.