Mineral Nutrition Status of Valencia Orange


 Fruit Production.-Records of fruit production for a three-
 year period (1953-54 to 1955-56) were obtained from the collabo-
 rators (Table A, Appendix). In view of the wide variations
 in planting distance observed from grove to grove, which may
 influence fruit production, the data were expressed on the basis
 of boxes per tree as well as per acre.
 Complete production records were not available on some
 groves. Consequently, fewer groves were used when the aver-
 age yield of all three years was considered.
 Fruit production from the survey groves showed a very wide
 range, whether expressed in boxes per tree or per acre. Ap-
 proximately 83 percent of the groves produced between 4.5 and
 8.5 boxes per tree. On the acre basis, 89 percent of the groves
 produced between 251 to 530 boxes.
 Fertilization Practices.-Among the different cultural prac-
 tices followed in the survey groves, fertilization showed the
 least agreement among the growers. The majority of the groves
 had been adequately, if not heavily, fertilized. Undoubtedly
 such practices were influenced to a certain extent by the favor-
 able market price of Valencia oranges during the survey period.
 Less than 20 percent of the groves were fertilized with rates
 below the adequate range.
 Most of the groves were fertilized three times a year, while
 11 groves (6.67%) received two applications and two groves
 (1.2%) were fertilized four times a year. Approximately two-
 thirds of the groves which were fertilized three times a year
 received one of the applications as a single nitrogenous com-
 pound, usually in the fall.
 Very few growers were using less than 0.5 pound of nitrogen
for every box of fruit produced. A few were using as high as 1
pound of nitrogen per box of fruit. The nitrogen application
ranged from 1.39 to 5.85 pounds per tree per year, with the
majority receiving 2.5 to 4.5 pounds. On the acre basis, nitro-
gen application ranged from 67 to 448 pounds, with the majority
between 200 to 250 pounds per acre per year. Because of the
differences in tree spacing, a grove which received large quanti-
ties of nitrogen based on pounds per tree did not necessarily fall
into the same category when the application was expressed in
pounds per acre. In general, more nitrogen was applied to each
tree in groves with wide space-setting than those in which the
trees were closely planted. However, when the data were ex-