Rice straw mulch (RC) is the vegetative part of the rice plant after the grain and chaff have been removed. The shape of RC is 40e60 cm long and 0.4e0.8 cm wide. The vetiver grass mulch (VGM) is composed of the leaves of vetiver grass which are 40e60 cm long and 0.6e1.2 cm wide. Both RC and VGM were dried in the sunlight for 1 wk before being used in this study