In a sickle cutting system, it has been found that a significant increase in ground speed while maintaining an acceptable level of cutting efficiency as measured by the average stubble length can be obtained by a combination of one or more of the features where the cutting stroke is reduced from the conventional length of 3.0 inches to a value of the order of 2.0 inches; the length of the cutting edge of each knife blade is increased to a length greater than 2.2 inches; the width at the rear of the ledger surface of each guard is increased to greater than 1.0 inches; and the front edge of the blade is formed with an apex to shed crop material to one or other side of the apex.