CEREALS ON THE BELLE FOUECHE EXPERIMENT FARM. 45 



the yield data. In 1913 and 1917 the earliest dates of seeding gave 

 the highest yields; in 1912, 1915, and 1916 the latest dates gave the 

 highest yields, while in 1918 the medium dates were most favorable. 

 The flax in the last sowing in 1915 did not emerge and that from 

 the earliest sowing of 1916 was blown out. Late summer rains in 

 1912 favored late sowing of flax, but in general the yields from flax 

 sown after May 20 were comparatively low. The best date of seed- 

 ing for flax on dry land at Newell, although undetermined, prob- 

 ably occurs between April 15 and May 15. The data are shown in 

 Table XXXII. 



EXPERIMENTS ON IRRIGATED LAND. 



In 1912 a large part of the Belle Fourche Experiment Farm was 

 placed under irrigation, and experiments with cereals on the irrigated 

 land were begun at that time. A few varieties of spring Avheat, oats, 

 barley, and flax were sown on irrigated land in 1912, 1913, and 1914. 

 In 1915 the number of plats was increased to include experiments 

 with winter wheat and grain mixtures, and in 1916 and thereafter a 

 number of additional experiments were in progress. The irrigated 

 plats were one twenty-fifth of an acre each in 1912 and 1913, but in 

 1914 and thereafter nearly all experiments were conducted in tripli- 

 cated fiftieth-acre plats. 



Most of the cereals grown under irrigation were sown on land 

 which had produced an intertilled crop, such as corn, potatoes, roots, 

 or sunflowers, the previous year. The land was double disked and 

 harrowed or " floated " before seeding. The cereal crops received two 

 and sometimes three irrigations during the season. The time of irri- 

 gation was gauged by the condition of the soil rather than bj^ the 

 stage of growth of the grain, because it was practically useless to 

 irrigate until the surface soil was sufficiently dry and cracked to take 

 up water. The quantity of water applied was not measured, but was 

 approximately 4 or 5 acre-inches at each application. Water was ap- 

 plied by flooding from field ditches, which usually were constructed 

 along the ends of the plats. 



The average yields from the irrigated land are not greatly in excess 

 of those from the same crops grown on the d^y land. In 1915 the 

 yields on dry land were much higher than on irrigated land. 



From 1912 to 1915, inclusive, the irrigation experiments were con- 

 ducted on rather unfavorable soil, while in 1916 most of the crops 

 were damaged by soil blowing and rust. The irrigated grains were 

 sown on previously cropped land following either small grain or an 

 intertilled crop, while many of the dry-land experiments were con- 

 ducted on summer fallow. In most seasons the grains were sown on 

 the dry land earlier than on the irrigated land, chiefly because the 



