ISHS Acta Horticulturae 365: International Symposium on Current Developments in Mediterranean Tropical and Subtropical Fruit Production and Research
NITROGEN FERTIGATION OF VALENCIA ORANGE IRRIGATED BY DRIP OR MINISPRINKLER |
| Authors: | P.I. Orphanos, G. Eliades |
| 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. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
