Nitrogen and Phosphorus Changes in Soil and Soil Water after Cultivation

Table 3

Mean values of soil fertility tests for both the 0–20 mm and 0–100 mm soil depths after fertiliser treatments were applied. Values in brackets represent significance at 5% level. Values before the comma compare ploughed versus unploughed within a fertiliser treatment, while values after the comma compare fertiliser treatments with identical sod preparation. Within a row, items with the same letter are not significantly different when comparing 0–20 mm together or comparing 0–100 mm together (significant tests have not been applied between different depths).

Depth	Treatments		Concentration (mg/kg)
			Olsen P	Colwell P	Organic P	Total P	CaCl2 P	TN
Top 2 cm	10 kg/ha P	Unploughed	58.6 (a, a)	177 (a, a)	281 (a, a)	719 (a, a)	1.5 (a, a)	4600 (a, a)
		Ploughed	24.3 (b, a)	67.4 (b, a)	106 (b, a)	297 (b, a)	0.3 (b, a)	2320 (b, a)
	35 kg/ha P	Unploughed	60.2 (a, a)	187 (a, a)	297 (a, a)	737 (a, a)	1.5 (a, a)	4930 (a, a)
		Ploughed	32.2 (b, a)	86.8 (b, a)	137 (b, a)	330 (b, a)	0.5 (b, b)	2280 (b, a)
	100 kg/ha P	Unploughed	80.3 (a, b)	252 (a, b)	365 (a, a)	799 (a, a)	2.9 (a, b)	4600 (a, a)
		Ploughed	50.9 (b, c)	144 (b, b)	209 (b, b)	441 (b, b)	0.9 (b, c)	2440 (b, a)
Top 10 cm	10 kg/ha P	Unploughed	42.9 (a, a)	126 (a, a)	217 (a, ac)	580 (a, a)	0.6 (a, a)	4000 (a, ac)
		Ploughed	28.9 (b, a)	83.3 (b, a)	145 (b, a)	360 (b, b)	0.5 (a, a)	2700 (b, a)
	35 kg/ha P	Unploughed	43.0 (a, a)	131 (a, a)	218 (a, bc)	593 (a, a)	0.6 (a, a)	4200 (a, a)
		Ploughed	28.4 (b, a)	78.2 (b, a)	140 (b, a)	365 (b, a)	0.4 (a, a)	2900 (b, a)
	100 kg/ha P	Unploughed	49.3 (a, b)	132 (a, a)	225 (a, a)	468 (a, a)	0.7 (a, a)	3400 (a, bc)
		Ploughed	40.4 (b, b)	115 (a, b)	177 (a, a)	463 (a, a)	0.5 (a, a)	3200 (a, b)