Fertigation for Apple Trees in the Pacific Northwest
Fertigation is the application of nutrients through irrigation lines, during watering. In general, it is more readily adapted for use in micro-irrigation systems such as micro-sprinkler, microjet and drip than to more extensive systems such as sprinkler or furrow. It has the advantage of allowing fl exibility in the timing of nutrient additions, and under micro-irrigation, targeting the nutrients into the tree root zone with higher precision than possible with highpressure irrigation or rain-fed watering. It is particularly well suited to high-density production systems. Injection of nutrients into the irrigation line can be either passive (Venturi-type) or through pumps, which can proportion the amount of nutrient added to the fl ow. Th is paper will emphasize nutrient management with fertigation, not the design of fertigation systems.