Abstract |
A unique opportunity to study insecticide usage and residues was provided as the Cedar Bluff Irrigation District in Central Kansas developed from dry land farming practices with little insecticide usage to intensified crop production and heavy insecticide usage. A survey of pesticide usage in the District area was made, both before and after irrigation practices were initiated, to determine trends in both types and quantities of pesticides applied. Insecticide residue studies were made on an experimental, irrigated field. Annual applications of persistent and nonpersistent insecticides most likely to be used on crops in the District were applied at approximate, maximum recommended rates to both soil and crop foliage. Insecticide residues were determined in ground and surface water, soil, corn foliage and grain, at intervals throughout the growing season for several consecutive years. In addition, river and reservoir sampled at stations in the District were analyzed for insecticide residues. The findings indicate that insecticides at recommended maximum rates for 5 years on a 20-acre field, and use on adjacent dry land and in the newly developed irrigation district, did not contaminate ground water. (Author) |