Project Partners: Micron Sprayers Limited, AGCO, HGCA.
With funding support from the Defra Sustainable Arable LINK Programme, and industrial input from Micron Sprayers Ltd, AGCO and the Home Grown Cereals Authority, joint research between SRI’s Aerosols Group and weed scientists at Rothamsted resulted in the development of a precise and cost-effective method of weed spray control.
Driven by the environmental requirement to reduce pesticide use, and the need to reduce the cost of arable production, the development of this unique spray controller has been greatly welcomed by the agricultural industry.
One of the environmental indicators is the level of pesticides in water, for which the EC has set a limit of 1µg per litre. Since 1990 the water industry has had to spend over £1 billion removing pesticides from water to meet this EC Directive.
As weed and disease control can take up to 40% of the costs of production, a more targeted application of chemicals that had the potential to deliver cost savings of around 50%, provided a very strong economic driver!
What the scientists developed was the PatchSpray System, which uses spatial location technology to accurately map the weedy areas of fields, and then uses this to generate a so called ‘treatment map’ that is used to control the selective application of herbicide.
The position of the sprayer in the field is determined from a satellite-based navigation system i.e. the Global Positioning System - GPS. The spray boom is fitted with two or more sets of nozzles with different orifice sizes and split into different sections (usually four).
Under the control of pneumatic and solenoid valves, the PatchSpray system then selects the appropriate combination of nozzles, and line pressure to achieve the required dose for that area of the field, as determined from the treatment map. In this way the optimum spray quality, based on the droplet size distribution is maintained. This is critical to the achievement of biological efficacy, and to the avoidance of unnecessary drift.
“The PatchSpray controller is mounted on the sprayer itself. In the tractor cab there is a separate control unit to allow the operator to select different nozzle combinations for fertiliser, herbicide or fungicide applications, or operate the sprayer entirely in manual mode. The characteristics of the spray nozzles are pre-programmed into the PatchSpray controller. It is the first variable rate controller to be commercialised in Europe, that can offer a wide range of control over spray volume output (up to 5:1 ratio).” Professor Paul Miller, Director of Technology.
The whole spraying system not only gives precise control over the spray volume applied, but it can also record operations. This can therefore form an integral part of the record keeping and management procedures required as part of farm quality assurance schemes and allow operators to comply with all regulatory requirements to protect waterways and the general environment as well as avoiding mis-application. The technology, which is relatively low cost, can be produced as a retrofit kit for existing sprayers or built in as an integral part of new sprayers. _ Director of Technology, Professor Paul Miller.
“As a company we were very pleased to work with Silsoe Research Institute to develop a commercial Patch Spraying System. It has the right environmental profile and we believe there is a real place for it in today’s market place. The user of our first prototype, Mr Paul Steer, has been delighted with the system and considers that his cost savings over less than two years would more than pay for the unit.” John Clayton,Technical Director, Micron Sprayers Limited.
This article appeared in the March 2004 issue (no. 12) of the Silsoe Research Institute Newsletter, written by Professor Paul Miller.
