FRUITSETAND YIELD OF WASHINGTON NAVE/, ORANGE TREES IN RESPONSE TO SOME TRETMEMTS IN NEWLY RECLAIMED SOILS OF JSMAILIA GOVERNORATE

Abstract

This investigation has been canied out in two consecutive seasons (1996/97 & 1997/98) in the citrus grove of the Hort. Res. Sta. At El Kassasinlsmailia Governorate. Seven year- old Washington navel orange trees budded on sour orange rootstock, grown on sandy soil and inigated by the drip system were devoted for this study. The selected trees were nearly uniform in size and vigor, planted in square system of five meters apart and subjected to the same cultural practices used by the orchard management.

At all events, the present investigation involved three experiments: Experiment {I} Effect ofin1gation: Three levels of inigation water were used 1850,3700 and 5550 m3 per feddan yearly. Experiment {II} Effect of fertilization: Four doses of nitrogen 3b&60&90and 120 kg N/feddan/year in the form of mmnonuim nitrate devided into 14 equal ammounts from early Mm•ch till the end of September. Besides three levels of K : 100&168and 250 kg as K2S04 per feddanlyem• 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 important results could be summarized as follows: