Abstract :
A field experiment was conducted during the two successive summer seasons of 2012 and 2013 at the experimental farm of Sakha Agric. Res. Station, Kafr EL-Sheikh Governorate. This study was conducted to investigate the effects of gypsum, sulphur and organic fertilizer (rice straw compost) on soybean yield, its chemical composition and soil chemical properties under three levels of soil salinity5.00, 9.00and 13.00 dS/m. The experiments were laid in split plot design, where the main plots, were allocoted for soil amendments: control treatment,-Rice straw compost at rate of 4 ton fed-1, sulphur at rate of 800 kg fed and gypsum at level of 4tonfed 1 while the sub plots were allotted for soybean cultivars; Giza111, Dr 101, Giza35, Giza82, Giza83, Toano and Holyday. The treatments were replicated four times.The results can be summarized as follows:-1-The soybean yield and its components were significantly affected by salinity, soil amendments and soybean cultivars2-The highest soybean seed yield were obtained by Giza 35 and Giza83 under application of gypsum treatment at three levels of soil salinity3-The maximum values of N, P and K contents in the seeds were obtained by Giza111 .Giza 35 andGiza82 under gypsum treatment4-The highest straw yields were recorded from Toano and Holyday, cultivars5-Soilsalinity decreased as follows gypsum sulphur compost control in the soil at the end of experiments6-Availability of N, P and K of soil after harvesting of soybean plants were increased at S1and S2 especially with application of compost comparing to control7-Theseed yield as affected by cultivars which can be arranged according to tolerance for salinity as follows: Giza83 = Giza35= Giza111=Dr101= Holyday =. Toano Giza 82) at S1. (Giza83 = Giza35 Giza111. =Dr101= Holyday = Toano Giza82) at s2 and Giza83 = Giza35 Giza111. =Dr101 Holyday = Toano Giza82) at S3 under gypsum treatment respectively
