Using Different of Water Qualities to Quantify the Effect Salinity Threshold by Equation of the Straight Line, Maas and Hoffman Equation of Sorghum Bicolor Crop

The experiment was carried out during the spring season 2017-2018 in one the field theDepartment of Horticulture and Garden Engineering Collge of Agriculture, Al-Qasim GreenUniveristy, Soil used had the texture of Silty Clay loam and by using the design of the RCBD afterplacing the soil in wooden containers of dimensions (40 * 60 * 60 cm. to determine the salinitythreshold of the sorghum bicolor Moench (L.) Crop. Threshold to salinity was calculatedmathematically to soil and irrigation water to obtain a relative yield of 100%, based of the straightline equation were values were 6.8 and 2.1 dSm- 1 on the relay, and Maas and Hoffman (1977)equation values were 3.7 and 2.5 dSm-1on the relay. It was found that Sorghum Bicolor Crop. yieldachieved 100% yield when soil salinity and irrigation water was 4.5, 6.8 dSm-1on the relayaccording to the Food and Agriculture Organization of the United Nations Bulletin No. 29 (Ayersand Westcot, 1985).