Table 3. Statistical characteristic values of soil nutrients.

Indexes	Sample sites	Min.	Max.	Mean	SD	C.V./%
pH	300	3.69	8.35	5.56	1.03	18.57
SOM/g kg−1	300	0.53	74.11	30.33	15.10	49.77
AN/mg kg−1	300	34.80	306.43	140.70	55.15	39.19
AP/mg kg−1	300	5.47	288.69	92.63	65.23	70.42
AK /mg kg−1	300	10.96	634.85	217.08	139.02	64.04

Notes.

SOM, soil organic matter; AN, alkali-hydrolyzable N; AP, available P; AK, available K; C.V., coefficient of valiation.