A mower deck (100) has a pair of adjacent cylindrical cutting chambers (101, 102) with rotary cutting blades (104, 105). Each cutting chamber (101, 102) has a skirt (107, 108) with an air inlet (121, 122) next to a rear discharge chute (115) centrally positioned between the two cutting chambers (101, 102). A horizontal shield (127, 128) is over each air inlet (121, 122).