Canadian Forest Service Publications
Mobilisation et transformation physico-chimiques de la matière organique drainée sous l'influence d'un apport d'urée dans un humus brut. 1970. Hubert, G.; Gonzalez, A. s.n., S.l. Rapport d'information Q-F-X-10. 11 p.
Issued by: Laurentian Forestry Centre
Catalog ID: 15377
Series: Information Report (LFC - Québec)
Availability: PDF (download)
Urea applied in vitro on raw humus regularly watered (4 mm water/day) triggered a considerable mobilization of organic matter (about 3,000 lbs. per acre in 12 weeks for an application of 400 lbs. of N-urea). Losses in Fe are ten-fold while those in Ca, Mg, and K are slightly modified. An additional application of 400 lbs. of calcium carbonate reduces the losses of organic matter by half.
This additional amount of eluated organic matter, with respect to conditions prevailing before fertilization, is essentially made up of humic acids. The gel filtration curves (Sephadex) showed the presence of compounds of high molecular weight signifying, perhaps, a polymerization of fulvic acids under the influence of urea.