Rice Production as Influenced by Automated Alternate Wetting and Drying Technology in Different Plant Spacing Configurations

Abstract

This study investigated optimal automated alternate wetting and drying (AWD) depths and planting spacings to enhance water conservation and rice yield under upland conditions. Using a two-factor strip-block design, AWD at 5 cm above, 10 cm below, and 15 cm below the soil surface was compared against continuous flooding, with spacings of 15×15 cm, 20×20 cm, and 25×25 cm on NSIC Rc222 variety. Results showed that 5 cm AWD depth with 15×15 cm spacing produced the highest grain yield (6.64 t/ha), water use efficiency (1.15 kg/m³), and net return (PHP 55,955/ha). The automated system maintained 98.7% sensor accuracy. Significant interactions between AWD depth and planting spacing were observed for plant height, shoot-root ratio, panicle length, harvest index, and yield. These findings confirm that automated AWD technology can achieve yields comparable to those of lowland systems using only shallow-well water, offering a sustainable alternative for upland rice farmers.