<P> Originally, the grass on the putting greens was the wide - bladed Bermuda . The greens lost speed, especially during the late 1970s, after the introduction of a healthier strain of narrow - bladed Bermuda, which thrived and grew thicker . In 1978, the greens on the par 3 course were reconstructed with bentgrass, a narrow - bladed species that could be mowed shorter, eliminating grain . After this test run, the greens on the main course were replaced with bentgrass in time for the 1981 Masters . The bentgrass resulted in significantly faster putting surfaces, which has required a reduction in some of the contours of the greens over time . </P> <P> Just before the 1975 tournament, the common beige sand in the bunkers was replaced with the now - signature white feldspar . It is a quartz derivative of the mining of feldspar and is shipped in from North Carolina . </P> <P> The Masters has the smallest field of the major championships, with 90--100 players . Unlike other majors, there are no alternates or qualifying tournaments . It is an invitational event, with invitations largely issued on an automatic basis to players who meet published criteria . The top 50 players in the Official World Golf Ranking are all invited . </P> <P> Past champions are always eligible, but since 2002 the Augusta National Golf Club has discouraged them from continuing to participate at an advanced age . Some will later become honorary starters . </P>

Number of players in the masters golf tournament