... importantly in maintaining the fertility of soil; preventing the increase of diseases, pests, weeds; and controlling and limiting erosion. Since 1980 in the Southern region in China, there ... plants on hilly land in Dong Hy district, Thai Nguyen province The model was conducted in 2007 - 2009 in Ao Son village, Minh Lap commune, Dong Hy district, Thai Nguyen province. Tea variety ... of sustainable intensive tea farming models in Dong Hy district, Thai Nguyen province Incomes Treatment Yield (tons of dry tea buds/ha/crop) Incomes (1.000 ñ) Cost (1.000ñ) Interest...