Experiments were conducted in 1955-1957 to determine the merits of the use of gravel as a soil mulch material instead of a mixture of sand and gravel widely used in Kansu. The results showed that(1) the effect of the gravel mulch on the soil temperature was as favorable as that of the sand-gravel mulch, (2) the gravel mulch was more effective in retaining soil moisture and(3) the growth and yield of the wheat grown on gravel mulched soil were slightly higher than those on sand-gravel mulched soil. The possibility of lengthening the effective period of the gravel mulch and of operating of farm machineries in gravel mulched fields is discussed.