“…Foliage-applied urea N reportedly increased fruit set in avocado (1) and other species, presumably when the internal pools of N were limiting (8,13,18,22). Foliar uptake, metabolism, and translocation of urea is rapid in avocado (16) and other species (7,13,15,18,22). Using isotopically labeled N, it has been possible to demonstrate that rapidly developing inflorescences and fruits are a strong N sink (15).…”