Table 1.

Basic physicochemical properties of the field experiment sites at a soil depth of 0–40 cm.

Items∗	Shangshui			Kaifeng			Wenxian
	2013–2014	2014–2015	2015–2016	2013–2014	2014–2015	2015–2016	2013–2014	2014–2015	2015–2016
pH	7.81	8.07	7.92	8.13	8.39	8.15	8.27	8.40	8.29
TN	0.95	1.25	1.33	0.80	0.96	1.01	0.89	0.93	0.95
AEN	90.35	110.00	118.33	74.70	85.43	99.25	93.90	100.54	102.95
OM	16.68	18.47	18.78	12.96	14.86	15.12	12.57	13.93	14.02
APP	12.94	27.28	15.70	12.72	13.13	11.56	12.56	16.36	15.13
APS	116.88	124.67	119.30	136.26	164.25	157.75	190.59	191.50	176.59
Texture	LCBS	LCBS	LCBS	Clay	Clay	Clay	FACS	FACS	FACS

^∗TN, total N (g kg^-1); AEN, alkaline extractable N (mg kg^-1); OM, organic matter (g kg^-1); APP, available phosphorus (mg kg^-1); APS, available potassium (mg kg^-1); LCBS, lime concretion black soil; FACS, fluvo-aquic clay soil.