Toetsing emissiemodel substraatteelt : experimenten op praktijkschaal en in laboratoriumopstelling

An “emission model” has been developed for use in the assessment of plant protection products (PPP’s) for admission. The “ emission model “ should predict the size of the emissions of PPP’s and provide tools for the effective use. A comparison was made of model calculations with field measurements after dosing two pesticides. In two experiments, data were collected over the course of the concentrations of two dosed pesticides with the active substance pymetrozine and propamocarb. Practical measurements have been carried out on a pepper holding company and a gerbera holding. After dosing the two agents the concentration gradients in the water were measured during 4 weeks. In a laboratory set-up , the agents have been added to three treatments , namely, gerbera mature plants , cut-off gerbera plants and new rockwool blocks. Subsequently, the leaching of PPP’s in the drainage water was measured over three days. Model calculations and practical measurements were too far apart to indicate that the model is generically applicable. There is insufficient understanding of the processes, such as dosing, adsorption, degradation and adsorption to explain the results. In a small follow-up study in a cucumber crop at Wageningen UR Greenhouse Horticulture in Bleiswijk the behaviour of three via dripirrigation dosed chemical agents (dimethomorph, fluopyram, imidacloprid) was followed in detail.