Effects of treated sewage irrigation on paddy rice culture and its soil

A pilot study was performed in an experimental field at Konkuk University in Seoul, Korea, to examine the effect of treated sewage irrigation on paddy rice culture and its soil characteristics. Treated sewage irrigation did not adversely affect the growth or yield of rice; instead it resulted in about 10% (with dilution) or 50% (without dilution) greater yield than in controls. The strength of treated sewage was not a limiting factor and no lodging was observed in the rice culture even with a relatively high nitrogen concentration (up to 160 mg l−1). The paddy soil also was not generally affected, although there was an indication of salt accumulation in the field irrigated with the highest strength of treated sewage. Overall, the treated sewage irrigation to paddy rice culture was thought to be an acceptable process for final sewage disposal as long as it is adequately treated and used as a supplemental source of irrigation. Copyright © 2001 John Wiley & Sons, Ltd.