Table 6: Measured and estimated phosphorus flows (kg P ha−1 year−1) and selected quotients (kg P kg P−1) in the cropping systems at Apelsvoll, mean 2001–20101.

P flow Cropping system2 CA1 CA2 OA CM OM1 OM2 Fertilizer 29.8 29.5 0.0 15.0 0.0 0.0 Cattle slurry applied 0.0 0.0 0.0 9.6 7.9 10.9 P in seeds 2.6 2.7 0.7 0.5 0.5 0.2 Sum field P input 32.5 32.1 0.7 25.1 8.4 11.1 Harvested P3 24.1 20.5 8.8 21.0 18.2 20.7 Drainage and runoff P 0.2 0.1 0.2 0.3 0.2 0.2 Sum field P output 24.3 20.7 8.9 21.2 18.4 20.9 Field P budget 8.2 11.5 −8.2 3.9 −10.0 −9.8 Harvested P4/applied P 0.72 0.70   0.82 2.17 1.82

1Timestep used is the agrohydrological year (May–April), thus, covering the period May 2001–April 2011. 2Each system covers 0.18 ha, and consists of four rotation plots á 0.045 ha. 3Including the P removed with straw. Harvested grass-clover P was reduced by 10% to account for likely harvest-related losses under practical conditions (see Section  2). 4Not including P removed with straw.