EFFECT OF DATES AND SOURCES OF NITROGEN FERTO,JZATION ON YIELD AND QUALITY OF SUGARBEET UNDER SURFACE AND SPRAY IRRIGATION METHODS IN NEWLY RECLAIMED AREAS

Abstract

Two field experiments were carried out on a sandy soil at both regions (West Nubariya, under surface irrigation system and Al-Bustan, • under spray irrigation system) during the two seasons of 1996/97 and

1997 /98, to study the effect of sources, levels and application time of nitrogen fertilizer under surface and spray irrigation systems on growth, yield and quality of juice of sugarbeet (Beta vulgaris, L.).

The nitrogen sources; i.e, ammonmm sulphate (20% N) and ammonium nitrate (33. 3%o N) were used at the levels of 30, 60, 90 and 120 kg N/fad. Each level of each nitrogen form was applied as follows:

1) In two equal portions at 30 and 60 days after sowing.

2) In three equal portions at 30, 45 and 60 days after sowing.

3) In four equal portions at 30, 45, 60 and 75 days after sowing.

The obtained results could be summarized as follows:

I. Surface Irrigation System

1.1. Growth parameters

1.1.1. Leaf area/plant (LA)

Beet plants received ammonium nitrate fertilizer significantly exceeded those received ammonium sulphate in LA/plant at all growth stages in both seasons. Leaf area/plant was significantly increased by increasing nitrogen level from 30 up to 120 kg N/fad. at the most growth stages in the two seasons. The interaction between nitrogen sources and