Nitrogen and Phosphorus Changes in Soil and Soil Water after Cultivation

Table 1

Initial soil properties two weeks prior to ploughing (November 2 and 5, 2009).

	Total N (mg/kg)	Olsen P (mg/kg)	Colwell P (mg/kg)	Organic P (mg/kg)	CaCl2 P (mg/kg)	NH4^+ (mg/kg N)	NO3^− (mg/kg N)
0–20 mm depth (November 2, 2009)
Mean	5200	54	182	272	1.3	30	5.4
Minimum	4400	34	100	160	0.2	11	0.5
Maximum	6300	66	250	380	2.8	79	19
0–100 mm depth (November 5, 2009)
Mean	4400	41	132	208	0.7	20	7.3
Minimum	3800	30	96	140	0.2	8.3	0.37
Maximum	5600	54	180	290	1.5	60	27
Relative percentage difference of means comparing the 0–20 mm and 0–100 mm depths
	18.8	32.4	38.3	30.8	78.2	48.4	−26.0