Four field experiments were carried out at Ras Sudr Research Station, Desert Research Center, at South Sinai Governorate, Egypt., during two successive growing seasons, i.e. 2008 and 2009 the aimed of this investigation was aimed to study the effect of three levels of salinity i.e. 3500 , 5500 and 7500 ppm, three rates of organic manure i.e. control, 10 and 20 m³ / fad. well as study the effect of three irrigation interval i.e. 15, 30 and 45 days, three rates of organic manure i.e. control, 10 and 20 m³ / fad. and their interaction on yield and chemical composition of Ochradenous baccatus and Deverra tortuos plants. Yield and chemical composition were taken at 6 (first cut), 12 (second cut), 18 (third cut) and 24 (fourth cut) months after transplanting. The results could be summarized as follows: 1- Fresh and dry yields and crude protein % of Ochradenous baccatus and Deverra tortuosa were higher when grown under salinity concentration of 3500 ppm and 20 m³/fad. while total carbohydrates and crude fiber % increased  organic fertilization at a rate by increasing salinity level up to 7500 ppm under control organic manure 20 m³ and, , at 6, 12, 18 and 24 months, respectively from transplanting.   2- Prolonging the irrigation interval from 15 to 45 days significantly depressed significantly fresh and dry yields and crude protein % and increased total carbohydrates and crude fiber % of two range plants. Increasing organic manure rates from 0 to 20 m³ / fad. increased fresh and dry yields, crude protein and total carbohydrates and decreased crude fiber % of Ochradenous baccatus and Deverra tortuosa at all growing periods. 3- Highest value of fresh and dry yields and crude protein of both range plants was obtained when organic manure was added at the rate 20 m³/fad at the low salinity level (3500 pp).  While, the highest yield of fresh and dry as well as crude protein for both range plants was obtained when organic manure was added at a rate of 20 m³/fad. at the narrow irrigation interval, (10 days) it could be summarized that to increase frash and dry yield of both two range plants by increasing the rate of organic manure up to 20m³/ fed. At different salinity levels as well as at the different irrigation intervals.