The influence of irrigation water salinity and fertilizer management on the yield of Alfalfa (Medicago sativa L)

A field study was conducted on a loamy sand soil to study the effect of water quality on growth and yield of Alfalfa (Medicago sativa L.). Treatments were replicated three times in a randomized split-split design, with water quality as the main plots, irrigation frequency as the subplots, and six nitrogen-phosphorus combinations as the sub-sub plots. Basin and sprinkler irrigation systems were used, Alfalfa produced good growth and dry matter yield under both canal (3.2-3.4 dS m(-1)) and mixed canal and drainage (6.4-8.6 dS m(-1)) irrigation waters whereas, irrigation with drainage water (10.2-15.6 dS m(-1)) reduced the yield significantly especially at biweekly irrigation frequency and at low nitrogen and phosphorus application, The high nitrogen level enhanced the growth of alfalfa and compensated for the reduction of its yield under high saline conditions. Under the experimental conditions the basin irrigation system was more appropriate compared with the sprinkler system for high alfalfa yield and leaching of salt build up in the soil in most of the cases studied.