2.2.11. Nitrogen fixation
Nitrogen fixation by growing legumes is a widely used practice
in arable farming world wide. Clovers are common features in
Canterbury arable rotations because of this nitrogen fixation.
These are used as a restorative phase between phases of crop
cultivations. The economic value of nitrogen fixed by different crops was estimated by the amount of nitrogen fixed per
hectare which was then valued at the unit price of urea (US
$0.84 kg−1) in New Zealand.