Key questions regarding nitrogen fertilization strategies for sweet cherries include:   —When is nitrogen needed for the various demands of the cherry tree growth cycle?   —Does the nitrogen needed for these demands come from soil uptake or remobilization from storage tissues? Our research has focused on when nitrogen is needed for the earliest stages of fruit and spur leaf growth, especially on precocious and dwarfing rootstocks like Gisela. Since cherries bloom, are pollinated, and set fruit concomitantly with spur leaf bud break, this critical phase of fruit formation occurs prior to the normal spring uptake of nitrogen from the soil, which […]