The Effect of Soil Treatment on the Response of the Soil Microflora to the Herbicide Dalapon

Responses of the soil microflora to the herbicide dalapon have been examined using three different soil treatments. The parameters examined were bacterial numbers and dehydrogenase activity. The effects of dalapon were less marked in soil cores sprayed with dalapon than in disturbed soil samples with herbicide incorporated throughout. Air‐drying of soil reduced the rate of disappearance of dalapon. The implications of these results are discussed in relation to the problems of designing sensitive tests which avoid exaggerated or abnormal effects of the agricultural chemical under test.