TEMPERATURE, MOISTURE AND COMPACTION AND THEIR EFFECTS ON THE DIFFUSION OF ETHYLENE DIBROMIDE IN THREE ONTARIO SOILS

Abstract

Three southwestern Ontario soils differing in texture were studied for penetration of the nematicide ethylene dibromide. A 3 × 2 × 2 factorial experiment was used that permitted evaluation of the effects of temperature, bulk density and moisture level in all combinations on response to the fumigant. The coursest soil (Fox loamy sand) showed the most rapid penetration, with moisture level, temperature and their interactions having the greatest effect on fumigant movement. On a medium-textured soil (Vineland silt loam) the degree of penetration was dependent on moisture, temperature and bulk density, with relatively small interaction effects, suggesting that effective fumigation depends upon careful soil management and timeliness of application. On the fine-textured soil (Lincoln clay) the fumigant did not move in the soil, regardless of edaphic factors, thereby explaining the difficulty of using fumigation to control nematodes on clay. The development of factorial methods and statistical techniques to study several variables concurrently should lead to more specific and effective methods of soil fumigation.