A pneumatic system of an agricultural implement includes a radial fan coupledwith aplenum. The plenum contains outlets which distribute the airflow into aplurality of productdistribution lines for application to a field. An airflow deflector plate hasa back face fixed on asidewall of a region interconnecting the fan outlet and plenum inlet to modifythe airflow patternand obtain an airflow that is at a uniform pressure and flow rate for eachproduct distributionline. The deflector plate is tapered with a narrow edge pointed upstream andincludes front facehaving at least one generally rectangular groove with a bottom surfaceextending generallyparallel to the deflector back face.
