Irrigated farms and tenure of farm operators, 1940 and 1930; irrigated area, 1939, 1929, and 1919; irrigable area and capital invested, 1940, 1930, and 1920; maintenance and operation, charges, and indebtedness, 1939 and 1929; and in irrigated farms, 1940; water delivered to irrigators and drainage of irrigated land, 1939
Drainage basin - area irrigated, 1939, 1929, 1919; capital invested and irrigable area, 1940, 1930, 1920; and irrigated units, maintenance and operation, charges, indebtedness, water delivered to irrigators, and drainage or irrigated land, 1939
Enterprises, area irrigated, capital invested, maintenance and operation, charges, indebtedness, and arrearage, type of enterprise, pay roll, number of employees, and source of water supply; by specified groups of irrigated units, areas irrigated, and cost of works: Census of 1940
The Census of Agriculture, taken every five years, is a complete count of U.S. farms and ranches and the people who operate them. The Census looks at land use and ownership, operator characteristics, production practices, income and expenditures, and many other areas.