Assessment of the influence of water management on yield component and morphological behavior of rice at post-heading stage.

The use of water saving (WS) techniques in irrigated rice production is a key factor to increase and sustain rice production in water scarce regions. The purpose of the present study is to evaluate the influence of water management upon phenology, morphology, yield components, and the relationship with soil chemical properties. Pot experiments were carried out in greenhouse, on two different soil types “Typic Fluvaquent (GS) and Typic Paleudult (RS)”. In both soils, five treatments were conducted under continuous flooding “Control” (T1), flooding-drainage at 2, 3, and 4 weeks after heading (T2, T3, and T4) and field capacity (T5). In terms of morphological components or grain yield, GS showed better performance than RS, the high Mn availability in RS was responsible for the poor performance. However, regardless of soil type the establishment of WS period at post-heading did not affect significantly any of the evaluated parameters compared with Control. Shifting from anaerobic to aerobic condition at GS-T2 increased grain yield (8 %), biomass (12 %), and root biomass (16 %) as well as reduced grain sterility by 15 and 14 % for GS and RS, respectively. On soil properties, the WS period showed that, GS-Fe availability as well as RS-Mn availability were reduced by 54 and 22 %, respectively, to more optimal levels in response to changes in redox potential (Eh) and reduction of pH. The results indicated that establishment of WS period at post-heading stage is a suitable strategy not only for reducing water input but also to improve morphological behavior, to reduce sterility as well as to control Fe and Mn availability without negative effects on grain yield.