Foliar‐Applied Nitrogen for Citrus Fertilization

Abstract

Abstract Fifty‐six “experiment‐years” of citrus data are presented which show that kilogram for kilogram, foliar‐applied N was as effective as soil‐applied N for fruit production. However, while one annual soil application sufficed to supply adequate N, three to six or more foliar sprays per year were required. “N‐production efficiency” (kg fruit produced per kg applied N) varied from 97 to 484. At or near the maximum nutritionally‐attainable yield, “fruit‐N‐removal efficiency” (kg N removed in fruit per kg applied N × 100) varied from 11 to 75%. The kg of N per 1,000 kg of fresh California citrus fruit varied from 1.15 to 1.73 and increased with increasing N rates.