We determined the dermal exposure of plant protection products containing prothioconazole (PTZ) after spraying a standard crop using a tractor‐operated boom sprayer. Dermal exposure of adult and child bystanders to PTZ and its metabolite, PTZ‐desthio was quantified in bystander drift studies. Exposure was greater on mannequins placed 2 m from the zero line, compared with 5 m or 8 m. When the overall boom height above the ground was the same, the relative boom and canopy heights had no impact on the spray drift, allowing pooling of data from different studies. Wind tunnel experiments were used to compare two flat fan nozzle types, which allowed dermal exposure measured in early bystander field studies using the flat fan TeeJet XR 110 03 nozzle to be adjusted using a conversion factor to reflect exposure from Hypro F110‐03 nozzles. Values from studies using both flat fan nozzle types were pooled and compared with exposure using drift reduction nozzles. For the first time, 3D life‐size mannequins used in field studies have shown that drift reduction nozzles exceed the EFSA‐recommended 50% reduction in drift (potential exposure was reduced by 58–67%). The BREAM2 (Bystander and Resident Exposure Assessment Model) model resulted in better predictions of measured dermal exposure of PTZ equivalents than BREAM, albeit producing more conservative values for the 75th and 95th percentiles of potential dermal exposure compared to field studies (2.6‐fold higher than measured values). Our results using measured potential and actual exposures indicate that the EFSA calculation of 18% protection by light clothing was too conservative.
Analysis of the yield and weed distribution in arable fields in a Geo Information System (GIS)
The variation in yield was assessed and mapped in cereals, maize, sunflower and faba beans at Dikopshof Research Station of the University of Bonn from 1998 to 2000 using a CERES 2 yield sensor (RDS® Company, Minchin‐hampton, UK). The calculated yields differed on average by 4–12 % from weighed grain yields depending on the crop and the grain moisture. The yield maps were georeferenced with a Geo Information System and compared to soil and aerial maps, field data and maps of the weed, nutrient and organic matter distributions to identify reasons for the yield variation. In two of the three fields studied, a strong correlation amongst grain yield, soil quality and relief map was found. In another field that was originally separated into two sections with different crop rotations, the distributions of grain yield, phosphorus, potassium and organic matter were still influenced by the former cropping system. On the basis of the results of this study, recommendations were made for site‐specific crop management. In addition, the results of this study contribute to elucidation of the complex influences of soil and management on the grain yield.
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