手法を比較

	陽イオン交換容量	土壌水分特性曲線
分野	農学	農学
系統	Process / pipeline	Process / pipeline
提唱年	1920-1982	1956-1980
提唱者	Georg Wiegner, Heinrich Rotter, Melvin E. Sumner	Willard Robert Gardner, Rollin H. Brooks, Arthur T. Corey
種類	Analytical soil characterization method	Empirical soil water retention model
原典	Thomas, G. W. (1982). Exchangeable cations. In A. L. Page, R. H. Miller, & D. R. Keeney (Eds.), Methods of soil analysis. Part 2: Chemical and microbiological properties (2nd ed., pp. 159-165). American Society of Agronomy.	Gardner, W. R. (1956). Representation of soil aggregate-size distribution by a logarithmic-normal distribution. Soil Science Society of America Journal, 20(2), 151-153.
別名	CEC, Soil nutrient retention, Base saturation	Water Retention Curve, pF Curve, Characteristic Curve, SWRC
関連	3	3
概要	Cation exchange capacity (CEC) is a fundamental soil property that measures the soil's ability to hold and release positively charged nutrient ions (cations: K⁺, Ca²⁺, Mg²⁺, Na⁺, H⁺, Al³⁺) in forms available to plant roots. CEC reflects the amount and type of clay minerals and organic matter in the soil—compounds with negatively charged surface sites that attract and temporarily bind cations. High CEC soils retain nutrients longer and require less frequent fertilization; low CEC soils lose nutrients rapidly through leaching.	The soil moisture curve (or soil water retention curve, SWRC) describes the relationship between soil water content and soil matric potential (water tension). It characterizes how tightly water is bound in pores of different sizes: large pores drain at low tensions (wet soils), while smaller pores retain water at high tensions (dry soils). Quantifying this relationship is essential for water balance modeling, unsaturated flow prediction, and assessing plant-available water.