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MODELED SEASONAL PATTERN OF NITROGEN REQUIREMENTS OF MATURE, CROPPING PEACH TREES (PRUNUS PERSICA (L.) BATSCH)
O’Henry) trees were estimated by combining models of organ dry mass accumulation and seasonal organ N concentrations.
Data for the models were collected from trees subjected to two different N treatments.
The study estimates and compares the N demand of perennial and annual organs during the growing season for both treatments.
Although N demand was higher for N-fertilized trees, seasonal N accumulation patterns were similar for both treatments.
Annual organs exhibited greater responses to N fertilization than perennial organs.
The average daily N demand per tree remained nearly constant from 40 days after anthesis to harvest.
Fertilized trees accumulated about 1 g N·tree-1·day-1, twice that of non-fertilized trees.
For the orchard studied, a daily demand of approximately 1 kg N·ha-1 was estimated for fertilized trees while approximately 0.5 kg N·ha-1 was required for unfertilized trees.
During the first 25–30 days, all N demand could be supplied by storage organs.
The release of N from storage organs for current growth was apparently completed in about 75 days in both treatments.