Deep-water rice production as influenced by time and depth of flooding on the east coast of India

The saucer-shaped landform, high rainfall due to the south-west monsoon (June–September) and poor drainage conditions make certain parts of the east coast of India susceptible to waterlogging during the rainy season. There is no alternative other than to grow rice in the coastal lowlands, where surface water accumulation of 0.5–2.0 m occurs during the rainy season. In this study, the physical environments of a representative deep-water ecology were characterized and the performance of improved deep-water rice (DWR) varieties (Hangseswari, Saraswati, Ambika, Sabita) was compared with that of local varieties (Bankei, Dhalakartik) at three water depths (shallow flooded [0.6–0.8 m], medium flooded [0.8–1.2 m] and deep flooded [>1.2 m]). The rainfall–flooding depth relationship was also studied and the probability of successful crop production in relation to the time and depth of waterlogging was investigated, based on historical (34 years) flood data from the region. Among the varieties studied, ‘Hangseswari’ was found to have superior physiological traits for growth, development and production of grain yield and hence may be considered for inclusion in further DWR breeding programs. With the introduction of improved DWR varieties, productivity during the rainy season was enhanced and farmers received good yield (2.05–2.95 t ha^?1) and net return (4500 Rs ha^?1).