Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Agricultural Engineering


Pesticides are applied to agricultural crops to maximize returns on the investment by the farmer. Granular pesticides are replacing liquid sprays in many applications. Granules are composed of a sorptive, inert carrier material impregnated with a toxicant which is released when the granules contact water. Application of pesticides by granular carrier has numerous advantages over liquid application: 1. Ease of handling and of application as no mixing or addition of water is necessary in the field. 2. Less drift because of particle weight, and thus reduced operator exposure to toxic chemicals. 3. Less total weight applied (10 to 20% of liquid weight usually applied). 4. Better residual effects and retention of strength during a continued drought. 5. More effective for pre-emergence applications. 6. Increased reliability due to soil incorporation. 7. Less expensive application since no tanks, pumps, nozzles or related accessory equipment are needed. Some disadvantages of granules are: 1. A uniform distribution requirement for proper protection at low application rates. 2. Higher chemical cost than sprays in most cases. 3. Soil moisture affects activation of chemical and its distribution. 4. Difficult calibration of applicator equipment. 5. 'Uniform application difficult because of: a. Low application rates. b. Variation in granule size, shape and density within and between pesticides. c. Field vibrations of the meter. (see more in text)

Library of Congress Subject Headings





South Dakota State University