Abstract:
In this study, glyphosate was used to determine the effect of increasing rate of application on soil Nitrogen mineralization. The experiment comprised three glyphosate treatments (i.e. 0.3546, 3.456,and 35.46 jug/g soil) with a control (without glyphosate). A Completely Randomized Design (CRD)was used with four replicates. Determination of NHf -N and N 0 3'-N were carried out at 1, 3, 5, 7, 10, 14, 21,35 and 56 days after herbicide application. Result showed that NHf -N content was not significantly (P < 0.05) reduced at the recommended
fie ld rate after one-day incubation. After 7 days and thereafter, no significant (P <0.05) changes were observed among treatments. Results also revealed that NO3-N content of the treatment 35.46 pg/g soil was significantly (P d ” 0.05) increased from the control after one and three days of Incubation period. Thereafter, significant (Pd n 0.05) changes were not observed fo r any treatment throughout the incubation period. Glyphosate had a positive effect on ammonification at all
Application rates, in spite of slight inhibition at the beginning of the experiment. In contrast, glyphosate showed no significant (P <0.05) stimulatory or inhibitory effects on nitrification. It could be concluded that nitrification was less affected by glyphosate even at higher rates (35.46 pg/g soil) and thus, application of glyphosate in red yellow podzolic soils would not be harmful to of N mineralization.
