12 BULLETIN 995, U. S. DEPARTMENT OF AGRICULTURE. 
Moisture. — Moisture is necessary for the production of profitable 
crops of sugar beets. This reaches the soil in the form of rain or 
snow, or it may be applied artificially. Our present sugar-beet area 
extends over a portion of the humid and the irrigated sections of 
the country, as shown in figure 1. 
In the humid sections the moisture falls largely during the winter ( 
months, although rains usually are frequent during the spring and 
summer. Occasionally some parts of the humid portion of our sugar- 
beet area are visited by heavy rains in the early spring, which greatly 
delay the planting of the beets as well as of other crops. This is 
sometimes followed about midsummer by a severe drought, which 
greatly retards crop growth. If these conditions were of frequent 
occurrence over wide areas, they would constitute a limiting factor 
in sugar-beet growing in the humid sections ; but they have occurred 
in this country only in limited areas and at long intervals. Occa- 
sionally rainfall is large at harvesting time, and sometimes injures 
the sugar-beet crop by producing a second growth of the plants, 
which greatly reduces the sugar content. The extent of this injury 
depends upon the condition of the beets and the duration of the rainy 
period. If this is followed by a period of favorable weather, the 
sugar content will be restored wholly or in part, depending upon 
the duration and nature of the weather. It sometimes happens that 
the beets must be harvested before the lost sugar is fully restored, 
either to prevent the roots from freezing in the ground or to avoid a 
temporary shutdown of the mill. Consequently a second growth due 
to late rains may cause serious losses to the grower and to the sugar 
company. A season in the humid region in which the rainfall is just 
sufficient to maintain a steady growth until near harvesting time, 
followed by continuous fair weather accompanied by cool nights and / 
warm days, makes conditions most favorable for the production of 
sugar beets so far as the humid area is concerned. These conditions 
prevail generally in the humid sections where sugar beets are grown. 
In the irrigated sugar-beet areas usually less than 20 inches of 
moisture falls during the entire year, and frequently many of the 
showers are so light that the} 7 are of no practical benefit in crop 
production. Sugar-beet growers in those sections depend largely 
upon irrigation. Frequently the showers that fall in irrigated areas 
are detrimental rather than helpful in the production of sugar beets, 
since they frequently cause the soil to crust. If this crusting occurs 
shortly after the seed is sown the young plants have great difficulty 
in breaking through to the light, with the result that the stands are 
very seriously injured and replantings are necessary. If the showers 
occur soon after the beets are up and the ground crusts around the 
young plants the air is cut off from the roots and growth is inter- 
