Mineral nutrients uptake from the soil in irrigated olive trees, cv Coratina, over six years after planting

The aim of the following work was to find out about the demand of mineral elements in an olive grove over the first years after planting in order to synchronise the demand with the offer of nutrients. The trial was carried out in Lavello (in the south of Italy) on young irrigated olive plants of cv Coratina. The trial determined dry matter during and at the end of each year, mineral element concentration in the various organs, pruning material and production. A removal evaluation was carried out for each mineral element in connection to the annual requirements for the canopy and roots growth and yield. The N removals went from the 4.5 kg ha-1 of the 2nd year to the 92.9 kg ha-1 of the 6th year. The P2O5 removals were minimal, going from 0.6 kg ha-1 in the 2nd year to 15.3 kg ha-1 in the 6th year; those of K2O, CaO and MgO were respectively of 4.3, 6.4, and 0.3 kg ha-1 in the 2nd year and of 81.5, 106.3 and 12.9 kg ha-1 in the 6th year. The amounts of removed Fe, Cu and Zn consisted in few g ha-1. The nutrient demand, compared to the total annual requirement, was relatively steady during the different phases of the year. The results show that the nutrient demand is, during the first years after planting, minimal and can be fulfilled by naturally supplied soils. The low doses of N have to be supplied through localised fertilization carried out during the annual season due to the constant demand by the plant. On the strength of the results of the trial and taking into account the water requirements, fertirrigation appears to be the most appropriate technique for the water and mineral nutrition of a young olive grove.