he center pivot system is the one of the most appropriate sprinkler systems for arid or semi-arid areas where a great deal of irrigating water. The system is used widely in Saudi Arabia, and there were more than 20,000 center pivot systems in the country. To know the reality of water application, water losses and distribution uniformity by this type of irrigation system in this country, a study was conducted in Riyadh region to evaluate 8 centers pivot systems with different ages and made of various companies and consisted of different number of towers ranged from 4 to 10. The results showed that most of the center pivot systems gave low distribution uniformity during water application at the irrigated areas. The values of coefficient of uniformity (Cu) were ranged between 69.2% and 89.2%, while the values of distribution of uniformity of low quarter (Du) were between 54.1% and 81.6%, and water losses from these systems were ranged between 7.83% and 13.57%. The study also investigated the effect of main factors on water distribution and water losses in arid areas by developing a statistical model in order to determine relationship between the losses and the factors affecting them under operating field conditions. The results of this study could assist the farmers to identify the irrigation and how to improve the system performance and the developed regression model could provide valuable information for the water application and water losses with center pivot irrigation system in region facing aridity and water scarcity.

No abstract

No abstract

A study was carried out at the Experimental Farm of the Faculty of Environmental Agricultural Sciences, Suez Canal University in El-Arish, during two successive seasons, 2004/2005 and 2005/2006. The experiment aimed to study the effect of irrigation intervals and distances between drip irrigation laterals on fodder beet (Beta vulgaris L. cv. VÖrÖshenger). The experiment was assigned for cultivating fodder beet plants. The experiment included 9 treatments for the interaction between 3, 5 and 7 days irrigation intervals and 40, 50 and 60 cm distances between drip lateral lines. Each treatment plot consisted of 3 lateral lines, each was 10 m long. The treatments plot area was either 12, 15 or 18 m 2 . Seeds of fodder beet plants were sown on the 1 st of October in 2 successive seasons, 2004/2005 and 2005/2006, at a rate of 3 kg.fed -1 . Actual evapotranspiration and fresh and dry yield of roots and top weights increased with decreasing irrigation intervals. However, they increased with increasing the distance between irrigation lines in both seasons. The water use efficiency increased with increasing irrigation intervals, while it was decreased with increasing the distance between irrigation lines. Treatment 3 days irrigation interval had the highest values of root and top content of crude protein, but it gave the lowest value of crude fiber and total ash content in both seasons. Treatment 7 days irrigation interval had the lowest root and top content of crude protein but it gave the highest crude fiber and total ash content in both seasons. The highest value of actual evapotranspiration was obtained at 3 days irrigation intervals with 60 cm distance between irrigation lines. The irrigation every 3 days with 60 cm distance between irrigation lines gave the highest yield, while the irrigation every 7 days with 40 cm distance between irrigation lines gave the highest water use efficiency.

This study was carried out at the Experimental Farm of the Faculty of Environmental Agricultural Sciences, Suez Canal University in El-Arish, during two successive seasons, 2004/2005 and 2005/2006. The experiment aimed to study the effect of irrigation intervals and distances between drip irrigation laterals on sugar beet (Beta vulgaris L. cv. PL12). The experiment was assigned for cultivating sugar beet plants. The experiment included 9 treatments for the interaction between 3, 5 and 7 days irrigation intervals and 40, 50 and 60 cm distances between drip lateral lines. Each treatment plot consisted of 3 lateral lines, each was 10 m long. The treatments plot area was either 12, 15 or 18 m 2 . Seeds of sugar beet plants were sown on the 1 st of October in 2 successive seasons, 2004/2005 and 2005/2006, at the rate of 3 kg.fed -1 . Actual evapotranspiration and fresh and dry yield of roots and top weights increased with decreasing irrigation intervals. However, they were increased with increasing the distance between irrigation lines in both seasons. The water use efficiency increased with increasing irrigation intervals, while it was decreased with increasing the distance between irrigation lines. The highest sugar yield was obtained when sugar beet was irrigated every 5 days, while the highest sugar beet was obtained for 60 cm distance between irrigation lines in both seasons. The highest value of actual evapotranspiration was obtained at 3 days irrigation intervals with 60 cm distance between irrigation lines. The irrigation every 3 days with 60 cm distance between irrigation lines gave the highest yield, while the irrigation every 7 days with 40 cm distance between irrigation lines gave the highest water use efficiency.