The objective of soil treatment is to reduce the numbers of weeds, insects, and disease-causing organisms in the soil and thereby promote plant vigor, increase yield and quality and decrease the need to use pesticides later in the production cycle. Soil treatments complement good disease control but do not replace the use of disease-free seed, cuttings, and transplants nor lessen the need for proper sanitation practices. Cold, wet soil reduces the effectiveness of fumigants and greatly increases the time required for the chemical to escape.
Dry soils allow the fumigant to escape too rapidly.
Pests in dry, cold soil are usually in a resting state which increases resistance to fumigants. See Crop Sensitivity to Soil Fumigants. Each material has recommended uses printed on its label and warns of possible damage to certain crops. Always read the label completely, particularly if herbicides or fertilizers are to be used on the same soil. Treatments must be carried out by applicators licensed in category.