Economics of site-specific weed control

The most important factors influencing the economics of weed control are the prices of herbicides and products, the competition through weeds and the seed production affecting weed infestation in following years. Treating weeds site-specifically leads to additional costs for weed detection and spatially differentiated herbicide application. With increasing accuracy these costs will rise, but on the other hand, weed control could be done more precisely. All the influencing factors: herbicide costs, the effects of competition, the effects of seed rain on future weed infestation, the costs for gathering information of the spatial distribution of weeds and the cost of applying chemicals in a spatially differentiated manner have a strong impact on whether site-specific weed control is economically viable or not. Simulation studies based on the assumption that reliable detectors of weeds in grain crops and sprayers with a direct injection system are available, show that savings of 15.- to 25.- Euro/ha can be expected. Taking into account the additional costs of generating digital weed maps, the additional cost for sprayers with direct injection systems and the costs of unavoidable application mistakes, these results show, that additional research has to be done to improve the economics of site-specific weed control.