Table 7: Measured and estimated potassium flows (kg K ha−1 year−1) and selected quotients (kg K kg K−1) in the cropping systems at Apelsvoll, mean 2001–20101.

K flowCropping system2

Cattle slurry applied0.
Wet atmospheric depositions2.
K in seeds11.411.
Sum field K input104.2101.93.0148.877.4104.2

Harvested K370.446.89.3101.482.2112.0
Drainage and runoff K6.
Sum field K output77.050.912.6105.185.4114.3

Field K budget27.251.0−9.743.7−8.0−10.1

Harvested K4/applied K0.530.530.661.041.05
Drainage + runoff K/applied K0.
Drainage + runoff K/harvested K40.140.090.360.040.040.02

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 á0.045 ha.
3Including the K removed with straw. Harvested grass-clover K was reduced by 10% to account for likely harvest-related losses under practical conditions (see Section 2).
4Not including K removed with straw.