Until now, there are no ways for sustainable water use and water resource protection from pollution applicable to all of the countries, but water conservation and sustainable use of water should be a supreme work for each country if we think of a life for descendants and a good environment for human beings. Assuming that these are the latest goals for sustainable agriculture, researchers in Korea having farms of small size and complex topography are attempting to introduce various systems for water and soil conservation. Water retaining capacity per ha of paddy fields in Korea was 5 times larger than that of upland, 3.5 times over forest area and 2 times over grassland. The total water retaining capacity on paddy fields was estimated at 23.8 billion tons for 1146 thousand ha in total, considering the present topographical condition. This quantity of water storage was equal to 47.6 times the amount of water kept in Youngweol Dam, which can store 0.5 billion ton year-1and for whose construction one billion dollars was taken. Therefore, the most appropriate type of farming in Korea, located in the Asia monsoon belt with heavy rain, was paddy rice farming. Although water use in paddy fields was larger than in uplands, putting water into paddy land played an important role for energy equilibrium through circulation between air heated in cities and that of surrounding rural areas. In the case of water quality, a new approach and concept considering land use, including paddy fields that are covering 61% of arable lands, is required to improve water quality contaminated by agricultural pollutants in Korea. This could be possible through a pollution load evaluation system, classification of watersheds by topographical characteristics & mother rocks, sub-classification of arable lands, assessment of erosion potential and a possibility of site-specific BMP (Best Management Practice) application in the field.