EFFECT OF ALTERNATIVE IRRIGATION WITH FRESH AND DRAINAGE WATER ON SUGAR BEET YIELD, SOIL SALINITY AND SOME WATER RELATIONS AT NORTH NILE DELTA, EGYPT

Two field experiments were conducted at Sidi Salim District, Kafr ElSheìkh Governorate. North Delta, Egypt to study the effect of the alternative use of high saline drainage water with fresh water for irrigation on sugar beet yield, yield components, soU salinity and some water relations during 2004/2005 and 200512006 seasons. The soil was saline and clayey in texture. Fresh water salinity and SAR values were 0.5 dS/m and 1.53 1respectively, while drainage water salinity and SAR values were 7.21 dS!rn and 14.4, respectively. Seven irrigation treatments were arranged in randomize complete block design with four replicates as follows: (A )1 00% fresh water.(B) 75% fresh water + 25 % drainage water. (C) 62.5% fresh water + 37.5 % drainage water.(D) 50% fresh water + 50 % drainage water.(E) 37.5% fresh water + 62.5 % drainage water. (F) 25% fresh water + 75 % drainage water.(G) 100% drainage water. The important findings could be summarized as follows :-. Using the alternative irrigation of drainage water with fresh water increased seeds emergency percentage compared to full irrigation with drainage water.- Reduction of root yield was 18.93 and 26.24 % when drainage water was used by 50% with fresh water during the two successive seasons, respectively. - Applying 25 to 50 % drainage water alternativety with fresh water resulted in a significant increase in sucrose percentage compared to control treatment in the 1st season while n the 2nd season sucrose percentage significantly was decreased with increasing the number of irrigations with drainage water. - There were no significant differences in extracted sugar yeld between the control and treatments B and C which received 25 and 37.5 % drainage water. While ¡n the second season au drainage water treatments caused high significant reduction in sugar yield. - The highest values of applied water and water consumptive use were obtained under irrigation with fresh water but decreased with increasing drainage water usage for irrigation. - Irrigation with fresh water achieved the highest values of field water use and crop water use efficiencies for root and extracted sugar yields. - Continues irrigation with drainage water increased soil salinity and alkalinity, while the cyclic irrigation by drainage and fresh water decreased them. it could be concluded that the sahne drainage water(4416 ppm) could be used at non sensitive plant growth stages ¡n percentage 50 % with fresh water for irrigating sugar beet with expected yield reduction percentage 25 %.