Response of Rice Yield and Soil to Sulfur Application under Water and Salinity Stresses

Abstract

TWO FIELD experiments were conducted at El-Sirw Agricultural Research Station, Damietta Governorate, Egypt during summer seasons of 2015 and 2016 to investigate the effect of three irrigation intervals ( 3 , 6 and 9 days ) and four soil application of sulfur rates ( 0 , 200 , 400 and 600 kg S/ ha ) and their interaction on the soil properties , growth characters, yield and yield components as well as water productivity of rice under saline soil conditions. In each experiment , strip plot design with four replications was used , where the horizontal plots were devoted to the irrigation intervals and the vertical plots were allocated by the sulfur rates. Irrigation every 3 days significantly decreased the values of the soil chemical properties studied , i.e. soil acidity (pH) , electrical conductivity (EC) and bulk density but significantly increased growth characters , i.e. chlorophyll content, leaf area, dry matter production and number of tillers/ hill and plant height as well as yield and yield components, i.e. number of panicles/ hill , panicle length , panicle weight, number of filled grains/ panicle , fertility % , 1000-grain weight , grain and biological yields/ ha and harvest index as compared with irrigation every 6 and 9 days. However , irrigation every 9 days significantly increased the number of unfilled grains/ panicle. Increasing soil application of sulfur rates up to 600 kg S/ ha decreased the values of soil properties (pH , EC and bulk density) as well as significantly and gradually increased the aforementioned growth characters as well as yield and yield components but significantly decreased number of unfilled grains/ panicle. The interaction effect between irrigation intervals and sulfur application rates , indicate that grain and biological yields/ ha were increased by the application of sulfur rates up to 400 kg S/ ha under short irrigation interval (3 days) and up to 600 kg S/ ha under medium and and long irrigation intervals (6 and 9 days). The irrigation of rice plants every 3 days consumed the largest amount of irrigation water, while prolonging the irrigation intervals up to 6 and 9 days led to a gradual decrease in the amount of irrigation water consumed by 12.99 and 37.31% , respectively compared with the irrigation every 3 days. Irrigation of rice plants every 6 days with the application of sulfur at a rate of 600 kg S/ ha produced the highest values of water productivity (0.296 kg/ m3 water) as an average of both seasons, indicating to the beneficial effect of the application of sulfur for improving soil properties , growth , yield and yield components as well as water productivity especially under prolonged irrigation interval in saline soil condition.