Land Use Changes Affecting Soil Organic Matter Accumulation in Topsoil and Subsoil in Northeast Thailand

Table 5

Mean squares for soil organic matter in different soil depths from four land use types and six locations.

Source of variation	Degree of freedom	Mean square	F-ratio
(a) One soil depth (0–100 cm)
Location	5	30493.50	195.14
Land use type	3	10480.40	28.16
Location × land use type	15	6533.70	17.56
Error	36	372.10
(b) Two soil depths (0–20 and 20–100 cm)
Location	5	15246.60	195.17
Land use type	3	5240.10	47.37
Soil depth^/1	1	31368.50	283.56
Land use type × soil depth^/1	3	1232.30	11.14
Location × soil depth^/1	5	2737.90	29.53
Location × land use type	15	3266.90	24.75
Location × land use type × soil depth^/1	15	1627.40	14.71
Error	84	110.60
(c) Five soil depths (0–20, 20–40, 40–60, 60–80, 80–100 cm)
Location	5	6098.70	194.99
Land use type	3	2096.30	77.28
Soil depth^/2	4	28746.70	1059.78
Land use type × soil depth^/2	12	653.30	24.08
Location × soil depth^/2	20	1224.90	48.17
Location × land use type	15	1306.80	45.15
Location × land use type × soil depth^/2	60	292.00	10.77
Error	228	27.10

Significant difference by LSD ().