chicago u.s. agriculture group push continue talk presumptive democratic republican presidential nominees effort influence farm policy position slump crop price squeeze sector profit representatives dozen trade associations include american farm bureau federation national farmers union meet staffers democratic candidate hillary clinton friday new york campaign headquarter farm coalition first meet clinton staff include discussions issue range agricultural trade labor mandatory label foods contain genetically modify ingredients attendees say wednesday meet start push sector detail clinton republican rival donald trump stances issue affect farmers agribusiness group seek meet trump campaign us agree side table successful meet first number exchange say jay vroom chief executive pesticide association croplife america attend session candidates agriculture policies crucial group say net u.s. farm income forecast drop low since 2002 largely due decline grain price happen incomes 56 percent recent high 123.3 billion 2013 kind climate definitely concern farm policy look like build next congressional farm bill say tom bryant national farmers union membership director elect clinton increase agricultural production profitability family farm spokesman tyrone gayle say trump spokeswoman immediately respond request comment matt paul former u.s. department agriculture spokesman work clinton campaign participate meet gather come day britain surprise vote exit european union draw support regions low population densities chandler goule incoming ceo national association wheat growers say farm group draw parallel britain referendum go rural america go turn election actually go determine outcome presidential election clinton trump presume nominees time start make detail in-the-weeds-type commitments say u.s. farm group discuss policy clinton staff pursue trump