by Inthong Somphou(Khon Kaen Univ., Khon Kaen (Thailand). Faculty of Agriculture. Dept. of Land Resources and Environment), Patma Vityakon(Khon Kaen Univ., Khon Kaen (Thailand). Faculty of Agriculture. Dept. of Land Resources and Environment), Vichai Sriboonlue(Khon Kaen Univ., Khon Kaen (Thailand). Faculty of Engineering. Dept. of Agricultural Engineering), Vidhaya Trelo-ges(Khon Kaen Univ., Khon Kaen (Thailand). Faculty of Agriculture. Dept. of Land Resources and Environment)
Published in Khon Kaen Agricultural Journal (Thailand) (01.04.2004)