1Diffuse reflectance spectroscopy (DRS) is increasingly being used to predict nu-2 merous soil physical, chemical and biochemical properties. However, soil properties and 3 processes vary at different scales and, as a result, relationships between soil properties 4 often depend on scale. In this paper we report on how the relationship between one 5 such property (CEC) and the DRS of the soil depends on spatial scale. We show this 6 by means of a nested analysis of covariance of soils sampled on a balanced nested design 7 in a 16 km × 16 km area in eastern England. We used principal components analysis 8 on the DRS to obtain a reduced number of variables while retaining key variation. The 9 first principal component accounted for 99.8 % of the total variance, the second for 10 0.14 %. Nested analysis of the variation in the CEC and the two principal components 11 showed that the substantial variance components are at the > 2000-m scale. This is 12 probably the result of differences in soil composition due to parent material. 13We then developed a model to predict CEC from the DRS and used partial least