DELEGATES at a precision farming (PF) conference in York (27 February) learned about the latest technological advances, with farmer and Nuffield scholar, Andrew Willamson, reporting on his findings from a study tour.

Mr Williamson described his visit to a farm in the US, which grows continuous maize and uses PF technology for sowing. The equipment uses a down force control mechanism, to achieve an even seed depth in fields with a range of soils and conditions.

“When the machine sensors detect softer ground, the seed is planted using a lower rate of pressure,” explained Mr Williamson, who runs a 900-acres arable farm in Shropshire. “Conversely, it exerts greater pressure in areas where the ground is harder. This technique ensures that all seeds are planted to a pre-set level.”

Another recent development he observed in the USA gives growers the option of sowing two separate maize varieties concurrently. A field is first divided into two management zones; one which retains moisture, for example, with a second area prone to drought.

The system will switch automatically between the two seed zones. This type of targeted drilling has been shown to improve profitability, by maximising the field potential. A four-year trial using this method produced an average yield increase of 0.53 tonnes/ha.

For weed control, the ultimate goal of any PF system is to correctly identify a species and target-spray the plant, said Mr Williamson. While visiting Germany, he witnessed a demonstration of the H Sensor, a machine which can distinguish between crops, grass and broad-leaved weeds.

The H Sensor is mounted 75cms in front of the nozzles on each section of the sprayer boom. The camera collects 10 images each second and switches the boom on or off, in response to the detection of weeds. When used in cereal trials, it has accurately identified blackgrass plants, with a success rate of 80%-90%.

Further studies have shown the potential of the H Sensor to reduce herbicide usage by 35%. This has been achieved by withholding chemicals on blackgrass-free areas of the field.

“Some large-scale PF systems might not be appropriate for the UK, with its high level of urbanisation,” said Mr Williamson. “However, there are potential savings to be made and producers could also use it to demonstrate the role that targeted chemicals can play, in protecting the environment.”

The conference was organised jointly by Gleadell Agriculture and Hutchinsons.