County-Scale Spatial Distribution of Soil Enzyme Activities and Enzyme Activity Indices in Agricultural Land: Implications for Soil Quality Assessment

Table 3

Parameters for variogram models of soil physicochemical properties, enzyme activities, and TEI in surface horizon (0–20 cm) of Changwu County ().

Parameters	Model			[/()]100	Range/km	RMSS
OM	Gaussian	3.03	4.36	69.53	9.3	1.09
Total N	Gaussian	0.02	0.04	57.05	7.49	1.05
Total P	Gaussian	0.04	0.05	77.74	6.26	1.05
Total K	Spherical	0.89	3.07	28.83	3.31	1.01
Alkali-hydrolyzable N	Gaussian	100.93	243.7	41.41	11.33	1.06
Available P	Gaussian	0.26	0.32	81.78	15.63	1.08
Available K	Exponential	0.19	0.21	89.89	10.27	1.01
CEC	Exponential	0.01	0.04	31.06	10.46	1.01
Clay	Exponential	7.18	24.64	29.14	5.23	0.97
pH	Gaussian	0.02	0.05	37.78	9.36	1.03
Invertase	Gaussian	16.89	27.93	60.45	3.89	1.00
Urease	Gaussian	8.87	10.4	85.34	9.36	1.02
Phosphatase	Gaussian	1.59	2.6	61.31	12.99	1.01
Catalase	Gaussian	1.32	2.44	54.27	5.33	0.98
Dehydrogenase	Exponential	0.19	0.27	71.26	1.99	0.96
TEI	Gaussian	0.65	1.30	50.15	0.84	1.07

, nugget variance; , structural variance; , sill; RMSS, root-mean-square standardized; OM, organic matter; N, nitrogen; P, phosphorous; K, potassium; and CEC, cation exchange capacity.