Use of Information Technologies for Precision Crop Protection

Yield may be reduced significantly when weeds compete with crop plants for light, water, and minerals. Weeds may also inhibit growth through release of allelopathic chemicals. Although several effective herbicides are available to control broad leaf weeds and grasses, they should be used only as an additional tool, not as a remedy. Herbicides continuously applied often lead to a shift in the weed population toward a difficult-to-control species. Most commonly, herbicide resistant species can replace sensitive ones. More alternatives to control weeds with less damage to environment are sought to offset this problem. An integration of control measures such as mechanical weed control is a good option; that is applicable not only to Organic Farming but also Conventional.
In order to be successful, the physical weed control should be performed under the parameter of selectivity. This is defined as the relationship between weed control and crop burial in soil as a result of post-emergence harrowing; crop yield response and weed recovery should be included as well. But selectivity depends on many factors, including some aspects: plant uprooting, tearing them into pieces and soil covering mechanism. They are fully related to the effectiveness of weed harrowing.
Concerning physical weed control in this project the main emphasis is on information technology, that means sensors for crop and weed detection, positioning and measuring of soil compactness combined with instruments for mechanical weeding. An automatic sensor for positioning (RTK-Differential GPS), a high-resolution bi-spectral camera for online green coverage detection (i.e. crop and weeds), and a sensor for quantifiying physical properties of the soil surface will be mounted on the front of a field vehicle. A tiny flexible harrow will be attached rearward of the field vehicle and an on-board control unit will analyse the sensor data and settle a decision of harrowing intensity.
The applied objective is to determine the best algorithm of selectivity in weed harrowing with the lowest damage to the cereals crops. The specific objectives are: to determine the efficacy of weed harrowing, to study the ability of the crop to resist and tolerate soil covering, to assess the soil resistance to harrowing, to assess the weed recovery post-treatment, to determine the crop yield response, and to perform real-time adjustments of the harrow tine. Field experiments on selective mechanical weed control and on real-time regulation of the system are underway.