Color, Organic Carbon, and Texture Relationships for A Horizons in Selected MLRA in Iowa, Illinois, Indiana, and Ohio.

The purpose of this study is to quantify the extent of the relationships between soil color, organic carbon, and texture. A total of 239 surface samples across five different MLRA thus far have been quantitatively analyzed for C content and color. C content was determined using a vario MAX CN machine. Munsell color both air-dry and moist was determined using a Konica Minolta CM-2500d spectrophotometer. C content of the samples ranged from .55% to 35.51%. Significant relationships were found between C content and Munsell value (r²=.40 dry, r²=.33 wet), Munsell chroma (r²=.35 dry, r²=.31 wet).The strongest relationship (r²=.63) was found between C content and wet Munsell chroma for samples from Ohio.  Upon initial analysis of C content and texture the only statistically significant relationship was with sand (r²=.14). This is expected to change when further particle size analysis is completed and they are separated by MLRA.