Soil loss study under different grasses strip and grasses hedge spacing against soil erosion on the highland   Vasuthep Kanchanadul, Nipon Udpuang, Sawasdee Boonchee   ABSTRACT         The project of soil loss study under different grasses strips and grasses hedge spacing against soil erosion on the highland was conducted on farmer field at Bansahakorn Moo 8, Tumbol Muang Ngai, Chiangdao district, Chiangmai province, on Li soil series, Soil group number 47, during the year 1995 - 1998. The experiment was randomized complete block design 4 replications, 5 treatments. The treatments were comprised of planting upland rice as farmer practice, planting upland rice between vetiver grass hedgerow with vertical interval of 1.5 meters, planting upland rice between vetiver grass hedgerow with vertical interval of 3 meters, planting upland rice between Ruzi grass strip with vertical interval 1.5 meters and planting upland rice between Ruzi grass strip with vertical interval 3 meters respectively.       The result of the study revealed that the treatment of planting upland rice between vetiver grass hedgerow with vertical interval of 3 meters and planting upland rice between Ruzi grass strip with vertical interval 3 meters were considered to be the most suitable conservation measure inorder to maximize the use of land for sustainable agriculture on the steep slope land of the northern Thailand.         Keywords : Soil conservation, highland.