Contribution of Parker and Product indexes to evaluate weathering condition of Yellow Brown Forest soils in Japan

Additionally, the indexes relations with soil color were studied after exposing the samples at a high temperature. Remarkable relationships between a* / b* ratio-parameters of psychometric chromaticness of color in CIE color standard system-and these two weathering indexes demonstrated that a* / b* ratio can be applied reliably to estimate the quantities of Parker and Product indexes in Yellow Brown Forest soils.