Soil-Landscape Modeling and Remote Sensing to Provide Spatial Representation of Soil Attributes for an Ethiopian Watershed

Table 3

Regression models to predict clay percent of the surface layer using terrain attributes and satellite images.

Class no.	Constant	Slope (%)	As	CTI	Aspect	Curvature	ASTER March	SPOT October	𝑅^2
1	17.69	0.07	0.00002	0.12	0.25	0.54	−0.004	−0.006	0.12
2	42.93	−0.33^∗∗	0.0001^∗	−0.75	0.31	1.08	−0.08^∗∗	0.04	0.50
3	39.16	−0.53^∗	0.0001	1.34	3.93^∗∗	−2.63^∗∗	0.04	−0.20	0.80
4	22.12	−1.37^∗	−0.0001	3.68	2.79	0.76	−0.02	−0.13	0.54
5	−2.82	−0.06	−0.0001	2.74	1.94	0.15	−0.01	−0.04	0.38
6	53.77	−0.25^∗∗	0.0001^∗∗	−1.20	−1.72^∗	−0.20	−0.05^∗∗	0.007	0.52
7	12.29	−0.18^∗	−0.00003	1.75	1.40	1.62	−0.01^∗	−0.04^∗	0.33

∗Significant at the 0.05 probability level; **significant at the 0.01 probability level.
As: upslope contributing area; CTI: compound topographic index.