Published online by Cambridge University Press: 27 March 2009
Eighteen trials were carried out to test factorial combinations of N, P, K and Na fertilizers on sugar beet over 3 years on deep light peat soils in the area surrounding the Wash. The average yield responses to all fertilizers were very small, and only rarely profitable, except to sodium. Nitrogen increased yield on a few sites, but there was no obvious way of distinguishing these, and on average there was no justification for using this fertilizer, which depressed sugar percentage. The difference from earlier work, which showed good responses to P and K, is ascribed to repeated heavy dressing of fertilizer given to these soils during the last two decades.