The effects of nitrogen fertilization and time of harvest on yield of zucchini
2002
Slociak, A. | Kolota, E. (Wroclaw University of Agriculture (Poland). Dept. of Horticulture)
In a field study conducted in 2000-01 the effects of different nitrogen rates applied as a single preplant dose or supplemented with one or two top dressings, on yield of zucchini Astra were estimated. During harvest the fruits at different stages of development with a length of 7-14, 15-21, and 22-30 cm were collected for determination of marketable and early yield, as well as their number per unit area. The results of the study showed that maximum marketable and early yield of fruits was assured by the application of 120 kg N/ha as a preplant dose, supplemented by the same amount of this nutrient in two top dressing doses. However, non-significant differences were found in the marketable yield of fruit between this treatment and those supplied with 180 kg N/ha in single or split dose. Harvest conducted at later stages of development increased yield but was associated with a considerable reduction in fruit number obtained from unit area. Heavy nitrogen fertilization caused an increment of total N content and nitrate accumulation in zucchini. Fruits harvested at early stages of development contained a higher level of total N, but smaller amounts of nitrates
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