Water and Soil Management for Water Conservation in a Watershed - Water and Agriculture: Sustainability, Markets and Policies - page 289

Chapter 19.
Water and Soil Management for Water Conservation
in a Watershed

S.O. Hur, K.H. Jung, Y.K. Sonn, S.Y. Hong and S.K. Ha 1

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 tonyear -1 and 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.

1.

Soil Management Division, National Institute of Agricultural Science and Technology Rural
Development Administration, Suwon, Korea.