Irrigation strategies with saline water in castor oil plant

Abstract

This experiment was conducted under field conditions to evaluate irrigation strategies with saline water on growth and production of castor oil plant (cv. BRS Energia), identify eventual stages with higher tolerance to salinity and monitor some soil chemical attributes. The treatments consisted of irrigations with water of EC 0.53; 2.09; 3.66 dS m-1 according to the development stage of the culture, totalizing five irrigation strategies with saline water and a control group. The growth evaluations were done at 20; 40; 60; 80; 100 days after sowing. The soil samples were taken at the same time of the growth evaluations, from the layers of 0 to 0.10; 0.10 to 0.30; 0.30 to 0.50 m. Continuous irrigation using water with EC of 3.66 dS m-1 reduced the plant height, length of tertiary raceme, number of fruits per area and fruit yield. This strategy increased the values of soil chemical attributes Na+ and EC at the end of cycle. From the 45th day on, irrigation with saline water did not damage the growth variables and the production components. This strategy minimized the negative impacts on the salinity/sodicity of the soil at the end of cycle. Similar behavior was observed for continuous irrigation using water with EC of 2.09 dS m-1 (mixing of water with EC of 0.53 and 3.66 dS m-1). The castor oil plant did not show different tolerance to salinity according to the development stage, although it was damaged with a longer and more intense saline stress.