FIUHT SET AND YIELD OF WASHINGTON NAVEL ORANGE TREES IN RESPONSTO SOME 'TRETMENTS IN NEWLY RECLAIMED SOILS OF .ISMAILIA GOVERNORATE

Abstract

This investigation has been canied out in two consecutive seasons (1996/97 & 1997/98) in the citrus grove ofthe H01t. Res. Sta. At El Kassasin lsmailia Govemorate. Seven year- old Washington navel orange trees budded on sour orange rootstock, grown on sandy soil and in•igated by •the drip system were devoted for this study. The selected trees were nearly unif01m in size and vigor, planted in square system offive meters apart and subjected to the same cultural practices used by the orchard management. At all events, the present investigation involved three experiments: Experiment {!} Effect of irrigation: Three levels of inigation water were used I 850,3700 and 5550 m3 per feddan yearly. Experiment {II} Effect of fe1tilization: Four doses of nitrogen 30&60&90and 120 kg N/feddan/year in the form of ammonuim nitrate devided into 14 equal ammounts from early March till the end of September. Besides three levels of K : I 00& 168and 250 kg as K2S04 per feddan/year added in three doses in March ,June and August. Experiment {III} Effect of mulching: Two soil mulchs were used i.e. 10 and 20 em thickness of straw mulch beside control treatment (unmulched). The most imp01tant results could be summarized as follows