Controlled-release sources of N and K were compared with soluble sources on young orange trees.The effects of these fertilizers on leaf mineral concentration, soil chemical analysis, and tree growth were evaluated for 3 years. Soluble fertilizers were generally more readily available but had shorter residual effects on leaves and soil than controlled-release fertilizers.
Advances in micro-irrigation techniques, drip and under-tree sprinklers, have facilitated more widespread adoption of fertigation, especially for perennial crops, including citrus. It is well known that fertigation improves nutrient uptake efficiency.