Influence of Rice-cultivation on Preferential Flow of Sodic Alkaline Soil in Northeast of China

By spraying applying Brilliant Blue as tracer, the improvements of a 1 year and a 5 year rice cultivation practice were quantitatively described in fields in comparison with a control in a sodic alkaline soil in Da´an county, Jilin Province of China. Brilliant Blue FCF solution with a concentration of 0.088 mol L^-1 was applied to the treated soils. Dye image was photographed layer by layer in the field after 24 h of spraying.. Results show that rice cultivation can improve alkaline soil structure and crack blocky structure to provide preferential flow, preferential pathway exists above 30 cm in the plot of 5-year-cultivation rice soil and 20 cm in the plot of 1-year-culitivation rice soil in contrast with control which virtually no obvious preferential in exists.