Vegetative growth and fruit set of olive (Olea europaea L. cv. ‘Zard’) in response to some soil and plant factors

This experiment was conducted to explore the reasons of difference between ‘Zard’ olive orchard with the poor vegetative growth rate and fruit set and orchard with suitable vegetative growth rate and fruit set in relation to some soil and plant factors during two seasons. Note that assumptions were based on the overall canopy greenness of the olive trees, so experimental orchards in which the planted trees showed optimum leaf greenness were considered good situations for optimum vegetative growth and productivity. Remote sensing technologies based on normalized difference vegetation index (NDVI) were employed on olive orchards, and two orchards meeting the criteria of highest amount of greenness and lowest amount of greenness were selected. Length of current-year shoot (LCYS) and fruit set were considered indicators of tree vegetative growth and productivity, respectively. Results clearly indicated a significant difference between the two selected orchards in terms of canopy volume (CV), leaf nitrogen content (N), leaf potassium content (K), silt, sand, Sodium adsorption rate (SAR), available phosphorous (Pavi), total neutralizing value (TNV), electrical conductivity (EC), chloride (Cl), and Fe variables. A stepwise regression method was used to evaluate the effects of soil and plant variables on fruit set and LCYS. According to the obtained results, the main reasons for differences between two orchards in fruit set and vegetative growth was N and K deficiencies, soil salinity, and a high percentage of silt in the soil.