EFFECTS OF PESTICIDES UPON NITROGEN-FIXATION AND NODULATION BY DRY BEAN

The effects of seven fungicides, seven herbicides and six insecticides on nitrogen fixation and nodulation by the dry bean (Phaseolus vulgaris L. cv “Bonus”) were investigated. All pesticides examined were found innocuous to nitrogen fixation (acetylene reduction) except bentazone, a post‐emergence herbicide. Bentazone at 3 × label rate (6.7 kg ha−1) consistently depressed nitrogen fixation rates within 48 h after application. However, rates recovered and were comparable to those of control plants after 6 days. No effects were observed on nodulation from any of the pesticides (3 × or label rate) applied. Copyright © 1990 John Wiley & Sons, Ltd