EFFECTS OF SALINITY AND NITROGEN ON LETTUCE UNDER ARID CONDITIONS | ||||
| Journal of Soil Sciences and Agricultural Engineering | ||||
| Article 5, Volume 25, Issue 10, October 2000, Page 6585-6598 PDF (599.46 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jssae.2000.259820 | ||||
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| Authors | ||||
| M. K. El-Haris,; K. N. Al-Redhaiman | ||||
| Soil & Water Dept. and Horticulture & Forests Dept., College of Agriculture and Veterinary Medicine, King Saud University, Al-Qassim, Saudi Arabia. | ||||
| Abstract | ||||
| Two pot experiments were conducted on a sandy soil to study the response of romaine lettuce (Lactuca sativa L.) cv. Parris Island to salinity and N fertilization rates and forms under the arid conditions. Equivalent amounts of 1:1 ratio Na:Ca in chloride forms were added to the water source of 1.4 dS m-1 to reach the desired salinity. Four salinity levels of irrigation water were obtained: 1.5, 3, 6, and 9 dS m-1 in 1997, and the latter level raised to 12 dS m-1 in 1998 winter season. The corresponding soil salinity measured on saturated soil paste extracts at harvesting were 2.6, 3.8, 6.2, and 10.1 dS m-1 in 1997 and 3.1, 4.9, 7.8, and 13.6 dS m-1 in 1998. Nitrogen fertilizers were added at 0, 150, and 300 kg N ha-1 rates in four forms: ammonium nitrate (AN), calcium nitrate (CaN), di-ammonium phosphate (DAP), and urea (UR) under each level of salinity. Data indicated significant reductions in lettuce yield and yield characteristics with increasing soil salinity. Application of 150 kg N ha-1 was adequate for romaine lettuce in sandy soils and no benefits were obtained with higher rates. Overall seasons, non of the N forms showed absolute superiority on yield or yield parameters and their significance were different between seasons of study. Romaine lettuce found to be moderately sensitive to salinity under the arid conditions. Its response function to salinity was developed. | ||||
| Keywords | ||||
| Romaine lettuce; Lactuca sativa L; salt stress; nitrogen fertilizer | ||||
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