S. Sulce et al., STUDY OF IMMOBILIZATION AND REMOBILIZATION OF NITROGEN-FERTILIZER IN CULTIVATED SOILS BY HYDROLYTIC FRACTIONATION, European journal of soil science, 47(2), 1996, pp. 249-255
Nitrogen immobilization and remobilization from a fertilizer were dete
rmined by hydrolytic fractionation of organic nitrogen with 6 M HCl in
to acid-soluble distillable nitrogen (NSAD), acid-soluble nondistillab
le nitrogen (NSAnD) and nonhydrolysable nitrogen (NnH) on the Ap horiz
ons of eight different soils from Myzeqe (Albania), eastern France, an
d tropical Mexico. The soils were fertilized with (KNO3)-N-15 and then
incubated at 28 degrees C and 80% of the water holding capacity for 1
month. Mineral N was removed by extraction with a solution of CaCl2 a
fter which rye grass was sown. The nitrogen taken up by rye grass was
thus derived from soil organic matter. The three NSAD, NSAnD and NnH f
ractions participate in both immobilization and remobilization. The NS
AnD fraction was shown to be the most active fraction. Remobilization
of the biomass was greater in the sandy brown soils than in the clayey
soils, in which intra-aggregate immobilization would predominate. Evi
dently, the physical and chemical properties of the soils have a real
bearing on immobilization and remineralization of nitrogen fertilizer
in cultivated soils.