Rice Yields Assessment of Reclaimed Wastewater Irrigation by the Fertilizer Changes in Paddy Fields

The objective of this study is to monitor and assess the rice yields of reclaimed wastewater irrigation by the fertilizer changes in lysimeter tests and paddy fields. Lysimeter tests were being implemented to cultivate rice with different levels of fertilizer applications of wastewater irrigation from 2002 to 2003. The field study, which was designed three treatments and three replications on 5m X 5m plots, was conducted from 2006 to 2008. The three treatments are separated according to the irrigation water: groundwater (TR#1), wastewater (TR#2), and treated wastewater with UV treatment (TR#3). The rice yield assessments by the fertilizer changes in reuse irrigation paddy fields was estimated by EPIC (Environmental Policy Integrated Climate) model taking into considerations the quality of wastewater effluent from wastewater treatment plants and the crop stress like water, nitrogen and temperature. Fertilizers were applied 100%, 75%, 50%, and 0% (no application) of the standard fertilizer amount. As a result, the treated wastewater irrigation plots have shown that reducing the standard application of chemical fertilizer by as much as 50 80% secured the harvest yield by the traditional cultivation. These results provide the reasonable management of reducing chemical fertilizer for agricultural reuse in paddy fields.