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 Avide 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 

 temporal^ 7 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 

 Avarm days, makes conditions most faA T orabk- for the production of 

 sugar beets so far as the humid area is concerned. These conditions 

 preA T ail 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 they 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 haA T e great difficulty 

 in breaking through to the light. AA T ith the result that the stands are 

 very seriously injured and replantings are necessary. If the shoAvers 

 occur soon after the beets are up and the ground crusts around the 

 young plants the air is cut off from the roots and groAvth is inter- 



