There were no significant differences between the average yields secured on the fall-irrigated plats and those on the check plats. Soil-moisture determinations were made in the spring and early summer each year. In 1914 they disclosed no significant differences in the moisture content of the soil resulting from fall irrigation except that in the first two of the three samplings more moisture was found in the first 3 feet of the fall-irrigated plats than in the corresponding depths of the check plats. No effect was noted beyond the third foot. The difference found in the upper 3 feet existed at a time when all the plats contained' abundant moisture, and it disappeared before the end of June. No significant differences were found in 1915 or 1916. The failure of fall irrigation to increase crop yields in these experiments seems to be attributable to the character of the soil at Belle Fourche. This soil is a heavy clay, which will absorb water only when dry and which expands rapidly when moisture is added to it. This expansion so compacts the soil as to make it impervious, so that the storage of water in the lower depths for the use of crops is not practicable. PUBLICATIONS OF THE U. S. DEPARTMENT OF AGRICULTURE ON RELATED SUBJECTS. AVAILABLE FOR FREE DISTRIBUTION BY THE DEPARTMENT. Experiments With Crops Under Fall Irrigation at the Scottsbluff Reclamation Project Experiment Farm. (Department Bulletin 133.) Sugar-beet Growing Under Irrigation. (Farmers' Bulletin 567.) Irrigated Pastures for Northern Reclamation Projects. (Bureau of Plant Industry, D. R. P.-2.) FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, GOVERNMENT PRINTING OFFICE, WASHINGTON, D. C. Progress Report of Cooperative Irrigation Experiments at California University Farm, Davis, Cal., 1909-1912. (Department Bulletin 10.) Price, 5 cents. The Flow of Water in Irrigation Channels. (Department Bulletin 194.) Price, 25 cents. The Drainage of Irrigated Land. (Department Bulletin 190.) Price, 10 cents. Potato Culture on Irrigated Farms of the West. (Farmers' Bulletin 386.) Price, 5 cents. Irrigation of Sugar Beets. (Farmers' Bulletin 392.) Price, 5 cents. The Use of Windmills in Irrigation in the Semiarid West. (Farmers' Bulletin 394.) Price, 5 cents. Irrigation of Grain. (Farmers' Bulletin 399.) Price, 5 cents. Irrigation of Orchards. (Farmers' Bulletin 404.) Price, 5 cents. Timothy Production on Irrigated Land in the Northwestern States. (Farmers' Bulletin 502.) Price, 5 cents. Suggestions to Potato Growers on Irrigated Lands. (Bureau of Plant Industry Circular 90.) Price, 5 cents. Irrigation in South Dakota. (Office of Experiment Stations Bulletin 210.) Price, 10 cents. Storage of Water for Irrigation Purposes: Part I. Earth-fill Dams and Hydraulic-fill Dams. (Office of Experiment Stations Bulletin 249, Part I.) Price, 30 cents. 15 ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM AT 5 CENTS PER COPY Δ WASHINGTON GOVERNMENT PRINTING OFFICE: 1917 |