Effect of soil amendment on properties of Samut Prakan saline soil and yield of taro   Suthat Prosayakul and Prasit Tanprapas   ABSTRACT        The Effect of organic matter and gypsum on physical and chemical properties of Samut Prakan saline soil and yield of taro were carried out at Samut Sakorn Land Development Station for 2 years (October1994-September1998). The experimental design was Randomized Complete Block Design with three replications.      The results showed that organic matter as farmyard manure, rice husk and compost applied singlely or in combination to gypsum decreased pH, ECe, exchangeable Mg++, Na+ and soluble Na+, but increased organic matter percentage, exchangeable Ca++, soluble Ca++, Mg++, Cl-, CO=3, HCO-3 SO=4 and available P. It also increased absorption by taro of N, P, Ca++, Mg++ and Cl-, but decreased absorption of Na+.      Bulk density of soil decreased significantly with addition to organic matter and gypsum.      Yield of taro was increased by single application of arganie matter or in combination to gypsum, but soil moisture could maintain above field capacity throughout growing season.        Keyword : Saline soil, amendment, taro