Articles
NITROGEN FERTIGATION OF VALENCIA ORANGE IRRIGATED BY DRIP OR MINISPRINKLER
Article number
365_9
Pages
105 – 120
Language
Abstract
Under the favourable climate and soil conditions of the SW coastal area of Cyprus Valencia orange trees yielded almost 100 t/ha by the time they were 12 years old.
Irrigation by minisprinkler or drip right from planting was equally good for tree development.
When the trees were five years old, an N experiment was initiated to test three levels of N. By then, the trees had received a total of 500 kg N, 110 kg P and 130 kg K/ha.
Over the first 3-year period of the experiment the N levels were 25, 50 or 75 ppm N in all the irrigation water applied, and resulted in the same yields.
For the next 3-year period these concentrations were reduced to 15, 30 and 45 ppm N, again in all the irrigation water applied.
At the end of this period yield under the lowest N level (mostly 100–120 kg N/ha/year) was 18% lower than under the two higher levels, and the trees had conspicuously less foliage.
The N levels were then increased to 25, 33.3 and 41.7 ppm N in the irrigation water, and all N is applied with the first 600 mm of irrigation so that fixed annual rates of N are given (150, 200 or 250 kg N/ha). Yield in the first year (1992) after this change, which is the last year reported here, continued to be lower under the N1 level.
Irrigation by minisprinkler or drip right from planting was equally good for tree development.
When the trees were five years old, an N experiment was initiated to test three levels of N. By then, the trees had received a total of 500 kg N, 110 kg P and 130 kg K/ha.
Over the first 3-year period of the experiment the N levels were 25, 50 or 75 ppm N in all the irrigation water applied, and resulted in the same yields.
For the next 3-year period these concentrations were reduced to 15, 30 and 45 ppm N, again in all the irrigation water applied.
At the end of this period yield under the lowest N level (mostly 100–120 kg N/ha/year) was 18% lower than under the two higher levels, and the trees had conspicuously less foliage.
The N levels were then increased to 25, 33.3 and 41.7 ppm N in the irrigation water, and all N is applied with the first 600 mm of irrigation so that fixed annual rates of N are given (150, 200 or 250 kg N/ha). Yield in the first year (1992) after this change, which is the last year reported here, continued to be lower under the N1 level.
Authors
P.I. Orphanos, G. Eliades
Keywords
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