In Iowa there are two sweet-clover regions, one in the eastern part of the state, and the other in the western part extending northward from Sioux City. There is also much white clover in eastern Iowa. Fair results may be obtained in almost every county in this state. The majority of successful beekeepers in Missouri are located near the Missouri and Mississippi rivers or their tributaries. When white clover fails on the uplands, a crop may usually be obtained from the fall flowers on the river-bottom lands. The southern part of the state is a much poorer section for the production of honey than the northern.
In the 17 arid and semi-arid western states, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Texas, Montana, Wyoming, Colorado, New Mexico, Idaho, Utah, Nevada, Arizona, Washington, Oregon, and California, there were, in 1920, about 19,000,000 acres under irrigation, and there were included in enterprises about 16,000,000 additional acres. In that portion of the United States lying east of these states the normal annual precipitation exceeds 26 inches, and is so distributed through the year as to provide sufficient water for the growing of general farm crops. In the Great Plains the normal annual precipitation ranges from 25 inches in the eastern portion to 15 inches in the western portion. In the Rocky Mountains there is a heavy snowfall on the summits, but in the valleys the precipitation is light and irrigation is necessary for growing crops. In the arid or desert region west of the Rocky Mountains and east of the Sierra Nevada Range the precipitation ranges from 8 inches in southern Idaho to 2 inches in southwestern Arizona. West of the Cascade Range and the Sierra Nevada there is a great variation in the rainfall. In western Washington and Oregon it is the heaviest of any part of the United States, but in late summer there is a dry period when irrigation is desirable. In California there is a well-defined dry period in summer and an equally well-defined wet period in winter. In the northern portion of the state the climate is nearly similar to that of Oregon, but in the southern portion irrigation is often necessary.
The streams in the western states have the common characteristics that they are subject to heavy floods in the spring and become very low in late summer. It is thus necessary to store the flood waters for use later in the season. The low water flow of the streams is exhausted, but there is a very large supply of flood water available for storage. The future extension of irrigation depends on whether the value of the crops will justify the storing of the flood waters, or the use of ground water by pumping. In 1919, water for about 85 per cent, of the acreage irrigated was supplied by streams and for 7 per cent, by wells. The other sources were chiefly lakes and springs.
In eastern North Dakota and eastern South Dakota there has been a very rapid increase of the area of sweet clover. The climate stimulates a very heavy flow of nectar. At present there are not many commercial beekeepers in this region, but there are hundreds of small ones. This region gives promise of being one of the best for bees in the whole of the United States. In the irrigated areas of the Black Hills there are thousands of acres of irrigated alfalfa. Excellent results are obtained in the Belle Fourche Valley.
In Nebraska, Kansas, and Oklahoma the future of beekeeping will depend largely upon the sweet clover acreage, which is steadily increasing. There are more than two million acres of alfalfa in these three states, but in the eastern portions it yields very little nectar, while in the central and western portions, where irrigation is practiced, it is a good honey plant. Beekeeping in Nebraska is most successful in the eastern part of the state along the Missouri River, where the honey plants are white clover, alsike clover, and sweet clover, and in the valley of the Platte River. Honey production in Kansas is most successful along the Arkansas River in the