Effectiveness of Field Water Tube for Standardization of Alternate Wetting and Drying (AWD) Method of Water Management in Lowland Rice ( Oryza Sativa L.)

Abstract

A field study was conducted to discover the effectiveness of a field water tube as a practical indicator for water management in lowland rice ( Oryza sativa L.). The field water tube was of 40 cm length and 15 cm in diameter so that the groundwater table could be easily visible. This tube with perforations was inserted into the ground until 20 cm protruded above soil level. It enabled monitoring of the water level inside the tube as and when the ponded water level drops to a certain permissible level, i.e. 5–15 cm‐surface. Practical indicators used in the experiment to find out the effectiveness of the field water tube were water stress parameters, viz. soil penetration resistance, soil crack width, soil siltation depth and days needed for ponded water to drop to a designated level in the field water tube. Field trials revealed that with 5 cm submergence depth and a threshold of 5 or 10 cm water depth below the ground level in the field the water tube was found to be a safe alternate wetting and drying practice in view of the higher yield (7060–7210 kg ha −1 ), considerable water saving (26.6–35.0%) and higher water productivity (1.15–1.27 kg m −3 ). © 2019 John Wiley & Sons, Ltd.

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