Fertigation of Deciduous Fruit Trees: Apple and Sweet Cherry

Nutrient uptake by trees is determined by root interception, soil availability, and tree demand. Fruit trees have low rooting density, especially in the case of dwarfing rootstocks. Mobility in the soil is a key factor in determining nutrient availability, and good management of nutrients requires that supply is matched to demand, in terms of amount, timing and retention in the root-zone, and that nutrients are placed where they can be accessed by roots. Fertigation allows such flexibility in the timing and precision of nutrient supply. The efficiency of N fertigation is closely related to irrigation management. Scheduling irrigation to meet tree evaporative demand minimizes the drainage of excess water through the root zone and the consequent N leaching. Timing the N supply to coincide with the period of rapid canopy development avoids excess N application when tree growth is supported by remobilization of stored N. Fertigation gives greater P and K mobility than broadcasting, increasing the potential for timely application of these nutrients in the root zone. P fertigation is beneficial at planting and as a single application at bloom. Fertigation with K can prevent the development of K-deficiency in drip-irrigated trees on sandy soil. Fertigation with acidic fertilizers through drip systems can be detrimental in coarse-textured soils, where it can result in soil acidification and nutrient deficiencies, which can develop in as short a period as three years.