Predicting off-site deposition of spray drift from horticultural spraying through porous barriers on soil and plant surfaces

Roberts, Tony and Mercer, Geoff and Oughton, Sean and Harper, Sharleen (2005) Predicting off-site deposition of spray drift from horticultural spraying through porous barriers on soil and plant surfaces. Australian and New Zealand Mathematics in Industry Study Group > 22nd MISG [Auckland 24/1/2005 - 28/1/2005].

Full text available as:

	PDF (Equation free summary) - Requires Adobe Acrobat Reader or other PDF viewer.
	PDF (Problem report) - Requires Adobe Acrobat Reader or other PDF viewer.

Abstract/Summary

New Zealand is a recognised leader in horticultural practices which include the use of boundary shelterbelts around orchards. These shelterbelts were primarily established to provide protection to the crop but are also an effective means of ameliorating agrichemical spray drift that may arise from the crop production area. Shelterbelt structure ranges from large trees (ranging from broad leaf to needle in structure) to hedgerows and artificial netting. The efficiency of the shelterbelt in capturing spray drift is known to depend on factors such as spray drift droplet size, wind velocity and the vegetation structure. However more specific information and models are required to define the capture efficiency to form part of a comprehensive spray drift management system.

Problem Statement

The task set the MISG team was to develop and investigate a mathematical model of shelterbelt efficiency. Factors such as wind profiles through and above the shelterbelts, release height of the spray drift, capture efficiency of different droplet sizes and evaporation rates all need to be considered. The object is to either produce a better working model or to clearly define the deficiencies in the existing models. Any model that is developed would need to be usable at the farm level. That is, any inputs to the model need to be easily measured or estimated quantities such as free stream wind velocity, optical porosity of the shelterbelt and typical vegetation element size of the shelterbelt. In practice barriers effective at trapping spray drift must have some airflow through them, solid barriers will direct airflow with spray droplets upward and over the barrier.

Archive Staff Only: edit this record