Advantages of Reduced Application Volumes
By
Alan McCracken
Contact: Alan McCracken E-mail: AlanMcCracken@bdmagro.com
Summary:
This paper deals with basic steps for an applicator to follow to improve the performance of agrochemicals with practical recommendations on the importance of the spray equipment in obtaining consistently good performance of the products. The recommendations are based on numerous trials and commercial application of various products under a broad range of conditions that have proven that the selection of the correct droplet spectrum is dramatically more important than the total volume of spray solution.
In seeking to obtain increased spray coverage, it is far more important and more economical to decrease the droplet size than to increase the spray volume. Data will be presented on the utilization of various methods of analysis of spray deposits.
Many entomologists/agriculturalists have always thought that higher volumes mean better coverage; this is erroneous and has led to the following:
• Poorer coverage of crop and pests as large droplets fail to penetrate dense foliage often due to mechanical limitation in atomization since higher volumes normally mean larger nozzles that result in larger droplets. Equally so with rotary atomizers when "flooded" with high volumes lose control of the droplet spectrum. Data on various systems will be presented.
• A slower rate of work by the equipment often resulting in spraying being conducted under adverse weather conditions in order to cover the area.
• Major problems with soil contamination, especially so when farmers apply very high volumes of 10 gals/acre or even more as in the case of the citrus crop.
• Increased application costs.
What are the advantages of lower spray volumes?
• Lower volumes are more effective for several reasons, however the most important is probably that the chemical ingredient is more concentrated enabling higher efficacy, such that one spray droplet may be adequate to kill a particular insect.
• Higher productivity of the aircraft in terms of acres/hour, as less time is wasted refilling with water enabling spraying to be finished before mid-day when the weather is usually less favorable.
• Lower application costs, especially so with the increased cost of fuel.
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