220 



PLANTS AND MAN 



until fifty years later when Napoleon encouraged its growth in 

 Germany and France as a part of his economic warfare on Great 

 Britain. With his fall from power, interest in beet sugar waned for 



almost thirty years, only to be 

 revived again in the two countries 

 mentioned where it has been in- 

 creasing in importance ever since. 

 The sugar beet industry has been 

 carried on successfully in the 

 United States since about 1880. 

 The plant (fig. 159) is a white- 

 rooted variety of the common 

 garden beet which develops best 

 in regions of warm summer tem- 

 peratures and cool fall weather, 

 such as exists in the northern parts 

 of the Great Plains region and in 

 the western mountain states. 

 Semi-arid regions that can be 

 irrigated, as well as naturally 

 moist, fertile soils are suited for its 

 growth. Sugar beets are grown in 

 rows, from seed planted in April, 

 and the final stand is thinned to 

 a spacing of eight to ten inches apart. Weeding, and deep culti- 

 vation by machine, are necessary during the growth of the crop. 

 The plants are harvested in October, the tops removed to 

 prevent any utilization of the sugar, and stored until ready for 

 transportation to the mill. Here the roots are cleaned, cut into 

 thin strips and exposed to hot running water in a series of tanks. 

 In this way 97 % of the sugar is extracted from the pulp which is 

 then used, wet or dried, as a cattle or sheep food. The non- 

 soluble and soluble impurities in the raw juice are removed by 

 being precipitated and coagulated after which the juice is 

 filtered free of them. This process may be repeated several times, 

 until a clear liquid is obtained which is then concentrated. The 

 sugar is crystallized and separated by centrifuging as in the 

 processing of cane sugar. The raw beet sugar obtained in this 



Fig. 159. — The sugar beet 

 plant is a white-rooted variety of 

 the common garden beet. 



