N, P, and K Budgets and Changes in Selected Topsoil Nutrients over 10 Years in a Long-Term Experiment with Conventional and Organic Crop Rotations

Table 2

Characteristics of the cropping systems at Apelsvoll, 2001–2010.

Crop rotation	Fertilizer, kg ha^−1			Slurry, kg ha^−1			Plant protection	Soil tillage
	N	P	K	N	P	K
Conventional arable (CA1)^1
Potatoes	119	51	183				Chemical, mechanical	Autumn ploughing and spring harrowing
Spring wheat	141	25	66				Chemical
Spring oats	120	22	57				Chemical
Spring barley	120	22	57				Chemical
Conventional arable (CA2)
Potatoes	108^2	47	164				Chemical, mech.	Spring harrowing only^7
Wheat + catch crop^3	134^2, 4	29	80				Chemical, mech.^5
Oats + catch crop^6	116^2	21	55				Chemical, mech.^5
Barley + catch crop^3	116^2	21	55				Chemical, mech.^5
Organic arable (OA)
Barley^8							Manual weeding	Spring ploughing and harrowing
Grass clover^9							Manual w.
S. wheat + catch crop							Manual w., mech.^5, 10
Oats + peas							Manual w., mech.^10
Conventional mixed dairy farming (CM)
Barley^11	50^2	9	24	70	10	90	Chemical	Spring ploughing and harrowing
1st ley year	99^2	16	75	57	8	73	—
2nd ley year	114^2	19	86	80	11	104	—
S. wheat + catch crop	86^2, 4	16	43	69	10	90	Chemical, mech.^5
Organic mixed dairy farming (OM1)
Barley^11				75	11	98	Manual w.	Spring ploughing and harrowing
1st ley year				24	2	31	Manual w.
2nd ley year				48	6	63	Manual w.
S. wheat + catch crop				83	12	107	Manual w., mech.^5, 10
Organic mixed dairy farming (OM2)
Barley^11				93	13	112	Manual w.	Spring ploughing and harrowing
1st ley year				63	8	80	Manual w.
2nd ley year				98	13	122	Manual w.
3rd ley year				75	10	93	Manual w.

¹Managed as was common for the region in 1985 (tillage and fertilization as in 1985, but for practical reasons, present-day inputs of seeds and chemical plant protection).
²Fertilizer level in spring adjusted according to regional recommendations, based on measurements of mineral N in topsoil in early spring. Average values are shown.
³Perennial ryegrass (Lolium perenne L), sown about one week after the cereals.
⁴Split application of fertilizer with about 75% given at sowing, and 0–60 kg N ha⁻¹ applied at growth stage (GS) 49, according to measurements with the N tester [6].
⁵Weed harrowing performed when the cereals are at GS 11-12.
⁶Italian ryegrass (Lolium multiflorum Lam), sown about one week after the oats.
⁷Performed twice with a horizontally rotating harrow.
⁸With undersown grass-clover mixture. Seed mix: 80% Timothy (Phleum pratense L.), 10% red clover (Trifolium pratense L.), and 10% white clover (Trifolium repens L).
⁹Green manure, not harvested but mulched 3-4 times per season.
¹⁰Harrowed in autumn after harvest some years to reduce the weed pressure.
¹¹With undersown grass-clover ley. Seed mix: 60% Timothy (Phleum pratense L.), 30% Meadow fescue (Festuca pratensis L.), and 10% red clover (Trifolium pratense L.).