Table 1. Major soil physicochemical characteristics of the experimental site.

Years	Soil depth (cm)	Bulk density (g cm−3)	Organic matter (g kg−1)	Total C (g kg−1)	Total N (g kg−1)	NH4+−N (mg kg−1)	NO3-−N (mg kg−1)	Avail. P (mg kg−1)	Avail. K (mg kg−1)
2012	0―30	1.23	12.20	15.80	0.67	3.80	10.56	36.5	130.4
	30―60	1.32	10.10	14.70	0.48	2.70	4.78	24.5	141.7
	60―100	1.38	8.70	13.90	0.17	1.90	1.53	15.6	117.8
2013	0―30	1.25	11.70	17.20	0.59	4.20	8.68	42.3	148.4
	30―60	1.37	9.40	15.50	0.37	3.10	4.02	22.8	135.7
	60―100	1.35	7.80	12.50	0.11	2.10	1.44	13.2	105.6