Persistence of 2, 4-dichlorophenoxyacetic acid in some local soils

Abstract

2, 4-D is a commonly used herbicide applied over large areas of forest and agricultural land. Its persistence in the soil depends partly on the properties of that soil. The persistence of 2, 4-D in five soils, local to Durham and with differing soil properties, was studied. Although differences were found, problems were encountered with the method of assay of 2, 4-D concentration, and it was thought that more time was required to use this method satisfactorily. 2,4-D sprayed on peat was much less available to seeds than it was when sprayed on the magnesium limestone soil, and was apparently either degraded very quickly, or locked up in the peat, with possibly a slow release later. However, it was possible to leach most of the 2, 4-D out of the peat, as easily as out of the magnesium limestone. 2, 4-D appeared to leach straight through a very dry soil, whereas much of it was held in the top soil when this was maintained at field capacity. Persistence of 2, 4-D'on the magnesium limestone in the field did not appear to be very different from that in the containers in the greenhouse. Nitrogen content of the soil appeared to be unaffected by spraying with 2,4-D.