Large scale rice production in the state of Arkansas became a significant industry in the late 19th/early 20th century with its wide scale propagation within the state by entrepreneur W.H. Fuller around 1896.
A cubic yard of sand approximately weighs 1.3 tons, 2,600 pounds ,or (for non imperial people) 1,179.34 kilograms.
Depending on the relative proportions of water, sand, stone, and cement, the weight per cubic yard can vary from less than 2000 lbs to nearly 3500 lbs; I would estimate most commercially (truck) delivered concrete would run close to 3300 lbs per cubic yard - remember there are 27 cubic feet in a cubic yard!