A COMPARATIVE STUDY ON THE EFFECT OF FAST AND SLOW-RELEASE NITROGEN FERTILIZERS ON NUTRITIONAL STATUS, YIELD AND FRUIT QUALITY OF LE-CONTE PEAR TREES UNDER RAFAH CONDITION.

This experiment was carried out for two successive seasons ( 1998 and 1999 ) on mature le – conte pear trees treated with two sources of bentonite coated urea as a slow release nitrogen fertilizer at 150 gm N/ tree/ year as
 ( BCU 1) with thin coated ( 4%) or( BCU 2)
 with thick coated ( 12%) , both added at one dose in March or at two equal doses in March and May. These treatments were compared with urea at 300gm N/tree/year
( the previously recommended dose ) as fast release N fertilizer added at one dose in  March  or at two equal doses in March and May or at   three equal doses in  March, April and May.
        Nitrogen and potassium in the leaves were significantly increased by slow  release fertilizer treatments in both seasons.
          The highest yield either as number or weight of fruits per tree, average fruit weight and volume were obtained by fertilizing trees with BCU2 at 150 gm N/ tree applied at one dose in March.
           Total soluble solids and total soluble solids / acid ratio were significantly affected by different treatments, while the other fruit characteristics were not affected in both seasons.
The use of (BCU2) at 150gm N/tree/year at one dose may be recommended for Le- conte pear trees grown in circumstances of Rafah orchard or similar to it.