More than 70% of the total rice cultivated areas in Thailand
are under rainfed lowland conditions, where rice is grown without
irrigation water and the grain yield is at low levels, ranging
from 1.5 to 2.2 t ha−1 (Jongdee et al., 2006). The major limiting factor of rainfed rice production is uncertain precipitation and fluctuating
soil water conditions. In this study, we focused on mild
intermittent droughts, which occur unpredictably and cannot be
avoided by shifting the transplanting date and using early maturing
varieties.