Estimating topsoil texture fractions by digital soil mapping - a response to the long outdated soil map in the Philippines

Table 4 The variogram parameters of soil texture fractions applying exponential, Gaussian and exponential models

Soil Texture fraction	Semivariogram model	Nugget effect, C₀	Sill [C₀ + C]	Nugget-to-sill ratio (C₀/[C₀ + C])	Structured part-to-sill ratio (C/[C₀ + C])	Effective range
Clay
	exponential	0.04	0.28	0.15	0.85	1560
	Gaussian	0.06	0.28	0.22	0.78	1900
	spherical	0.03	0.28	0.11	0.89	3800
Sand
	exponential	0.03	0.21	0.14	0.86	2360
	Gaussian	0.05	0.21	0.24	0.76	2920
	spherical	0.03	0.21	0.14	0.86	5600
Silt
	exponential	0.04	0.48	0.08	0.92	1250
	Gaussian	0.08	0.48	0.17	0.83	1570
	spherical	0.04	0.48	0.08	0.92	3490

ISSN: 2468-2039