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Factors influencing boom sprayer deposit variability - PA1725


The aim of the work is to identify the effect of application variables on the evenness of distribution of spray deposits under a boom, and to propose recommended operating conditions that will minimise the magnitude of variation in deposit of plant protection products. Experiments examining the variation in spray deposition at ground level will be conducted in field conditions and within a controlled environment (SRI wind tunnel), and will consider nozzle types, nozzle orientation, application rate, forward speed and cross wind velocity. The results from the field and wind tunnel deposition experiments will be interpreted using mathematical relationships relating to variables influencing droplet behaviour. The need to identify the variation in deposition and the principle components in that variation relates directly to the performance of plant protection products particularly in regions close to the field boundary where steps to control the risk of drift may lead to a less uniform spray distribution pattern. An improved uniformity of deposit on target surfaces below a boom has implications for crop residues, the dose rate of product required to achieve a given biological response and the contamination of non-target organisms. Results of the work are relevant to the development of codes of practice relating to the use of pesticides, risk assessments and evaluations of environmental contamination.

Overall To establish the degree to which various operational factors influence deposit variability associated with the operation of boom sprayers. This will involve:

1. The field measurement of surface deposits from a 24.0 m boom associated with at least six different application strategies including a range of forward speeds and nozzles at volume rates in the range 100 to 200 l/ha.

2. The measurement of spray deposition in a controlled environment, using the SRI wind tunnel facility. Examining the effect of nozzle type, nozzle orientation, wind speed and forward speed across the working width of a boom fitted with multiple nozzles.

3. A range of experiments measuring dynamic and static patternation to assess variation in application rate across the boom system for the various application system arrangements.

4. The interpretation of results from wind tunnel and field experiments, and comparison with predictions from existing mathematical models.

5. Establishing boom sprayer operational factors that deliver a relatively low drift risk and uniform spray distribution at ground level.

Project Documents
• Final Report : Factors influencing boom sprayer deposit variability   (148k)
Time-Scale and Cost
From: 2000

To: 2002

Cost: £88,817
Contractor / Funded Organisations
Silsoe Research Institute (BBSRC)
Pest and Weed Control              
Pesticide use              
Plants and Animals              
Fields of Study
Pesticide Safety