SAARELA, I., HUHTA, H. and VIRKAJÄRVI, P. 2006. Effects of repeated phosphorus fertilisation on field crops in Finland 2.Sufficient phosphorus application rates on silty and sandy soils. Agricultural and Food Science. 15, 4 (Jan. 2006), 423–443. DOI:https://doi.org/10.2137/145960606780061489.