Predicting and mapping soil available water capacity in Korea

Area of Science:

• Soil Science
• Environmental Science
• Hydrology

Background:

• Soil available water capacity is vital for terrestrial ecosystem water and energy balances, influencing evapotranspiration and climate.
• Accurate spatial data on soil water capacity is essential for regional and national environmental assessments.
• Understanding soil water dynamics is key to managing water resources and predicting climate impacts.

Purpose of the Study:

• To develop a protocol for fine-scale mapping of soil available water capacity in South Korea.
• To integrate digital soil mapping techniques with existing soil survey data for enhanced accuracy.
• To provide a valuable resource for assessing soil physical quality and water management strategies.

Main Methods:

• Utilized digital soil mapping technology combined with a 1:25,000 scale soil map of South Korea.
• Employed modal profile data from the Taxonomical Classification of Korean Soils, including physical and chemical analyses.
• Applied pedotransfer functions to predict missing bulk density and water content data, with a correction factor for water content at -10 kPa.

Main Results:

• Andisols exhibited the highest mean water storage capacity, followed by loamy Entisols and Inceptisols.
• Sandy Entisols showed the lowest water retention capacity.
• The western regions of South Korea displayed higher available water capacity compared to the mountainous eastern regions with shallower soils. Ultisols and Alfisols showed the highest water storage capacity (mean of 206 and 205 mm).

Conclusions:

• The developed protocol successfully generated a fine-scale map of soil available water capacity for South Korea.
• The resulting map provides crucial insights into the spatial distribution of soil physical properties and water storage potential.
• The map serves as a valuable tool for indicating the soil physical quality of Korean soils and informing land and water management decisions.