200

150

100





-00

-50
 -10


cnO
ID ~
-e
oo
lulu


-200


Figure 5-3. Monthly variation of total nitrogen mineralization, ammonification and nitriaication
 rates (mg-l kg-l month- ) obtained from field incubation of soils (untreated) during 14
 months before and after the 2002 treatments.


0 I I I I 1 ********
O Control o Oust a Velpar a Oust-Velpar m Arsenal


Treatments


Figure 5-4. Net nitrogen mineralization means mg (NH4+ + NO3-) / kg-l soil / month for the
 control, Oust: sulfometuron methyl, Velpar: hexazinone, sulfometuron methyl-
 hexazinone mix and Arsenal: imazapyr. Results are from soil samples collected
 during 14 months before and after the 2002 treatments.


 107


Nitrification


 a r
 'D"US~ In
 ~77 o
 ooooo, o
) IU IU IU IU N R)


 Ammonification