Abstract

This study was conducted to determine the effect of changing the depths of water and planting methods on soil properties and rice yields under alternate wetting and drying (AWD) in the Systems of Rice Intensification (SRI). The treatments consisted of four irrigation levels and four planting methods. The irrigation treatments included 4 water drop levels (WDL) in observation well: 6 cm, 10 cm, 14 cm water drop levels below the soil surface and continuous flooding with 5 cm layer of water above soil. Four planting methods included seed drilling, broadcasting, transplanting 12 dayold seedling and transplanting 21 day-old seedlings. Lowland rice (FARO 44) was established in randomized complete block design. Alternate wetting and drying at 6 and 14 cm WDL showed 14.27 % and 11.59 % increase in total porosity respectively, when compared with initial soil total porosity. All plots showed a decrease in bulk density compared with initial soil bulk density. Paddy yield for irrigation treatments ranged between 6.03-9.92 t ha-1, with AWD at 10 cm WDL having highest yield of 9.92 t ha-1, the lowest was observed in the continuously flooded plots (6.03t ha-1). System of rice intensification method of transplanting was observed to yield 10.08 t ha-1 of paddy and showed percentage increases in paddy yields by 26.3%, 69.9% and 33.5% over conventional transplanting (21 day seedling), broadcasting and drilling, respectively. This study showed the superiority of using younger seedlings in transplanting and 10cm water drop level in the observation well for increased food security and income.