Water management in irrigated rice - Rice Knowledge Bank ...
Water management in irrigated rice - Rice Knowledge Bank ...
Water management in irrigated rice - Rice Knowledge Bank ...
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Appendix: InstrumentationDetailed descriptions and user guides of equipmentto measure water flows and soil physical andhydrological properties of <strong>rice</strong> soils are given byIRRI (1987) and Wopereis et al (1994). Calculationand measurement procedures for evapotranspirationare given by FAO (1998). Here, we <strong>in</strong>troduce twosimple tools that are practical <strong>in</strong> characteriz<strong>in</strong>g thewater status (hydrological conditions) of <strong>rice</strong> fieldsand can help guide the implementation of watersav<strong>in</strong>gtechnologies.A.1 Field water tubeThe field water tube is used to measure the depth ofstand<strong>in</strong>g water on the field, be it on top of the surfaceor just below the surface (Fig. A.1). PerforateWith stand<strong>in</strong>g wateron top of the surface:read this20-cm-diameter PVC pipeUse a ruler tomeasure water depth15 cmSoil surfacePuddledtopsoil20 cmWith water belowthe soil surface:read thisPlow panHoles are 5 mm <strong>in</strong> diameter,and spaced 2 cm apartFig. A.1. Field water tube for monitor<strong>in</strong>g the depth of stand<strong>in</strong>g water on a <strong>rice</strong> field.45