Table 3.

Overall mean average annual soil carbon, nitrogen and phosphorus balance^a (for the whole profile) for arable and grass lands estimated based on simulation results for different time periods for whole of the UK.

Components	1800–1950		1950–1970		1970–2010
	Arable	Grass	Arable	Grass	Arable	Grass
Soil organic carbon (Mg ha−1 y−1)
Plant C input	1.01	2.88	0.99	3.40	1.05	3.86
Animal C input	0.01	0.70	0.02	0.65	0.03	0.75
Dissolved organic carbon loss	0.00	−0.04	0.00	−0.04	0.00	−0.04
Particulate organic carbon loss	0.00	−0.01	0.00	−0.01	0.00	−0.02
Carbon loss (by decomposition as CO2)	−1.2	−3.33	−1.25	−3.53	−1.16	−4.30
Net carbon change	−0.18	0.20	−0.25	0.47	−0.08	0.25
Mineral nitrogen (kg ha−1 y−1)
Atmospheric N deposition	3.9	4.03	8.8	9.09	11.5	11.91
Fertilizer N input	8.1	2.03	64.0	35.0	127.9	134.8
N input by mineralisation	38.7	67.3	41.0	65.92	41.4	81.73
Animal N input	0.9	43.2	2.1	41.44	2.9	48.53
N input by biological N fixation	0.0	47.4	0.0	54.30	0	43.4
N loss by leaching, runoff and soil erosion	−14.9	−17.7	−29.0	−21.47	−52.3	−36.02
N loss by denitrification	−0.3	−0.28	−0.78	−0.38	−1.49	−0.61
Plant N uptake	−35.9	−144.9	−79.3	−173.9	−128.9	−283.6
Net N change	0.50	0.98	6.8	10.0	1.0	0.14
Mineral phosphorus (kg ha−1 y−1)
Fertilizer P input	8.7	2.34	26.4	16.67	34.6	14.54
P input by mineralisation	5.6	10.2	6.6	9.19	5.41	11.62
Animal P input	0.10	8.0	0.2	7.75	0.32	7.93
P loss by leaching, runoff and soil erosion	−0.03	−0.03	−0.14	−0.05	−0.28	−0.14
Plant P uptake	−11.8	−17.8	−22.3	−22.25	−22.0	−30.34
Net P change	2.57	2.8	10.8	11.3	18.05	3.61

^aA Positive sign indicates input or gain and negative sign indicates loss from the soil system.