144 ELEMENTARY AGRICULTURAL CHEMISTRY 



the root entirely underground, and should be, compared with 

 ordinary mangolds, small in size. The best probably weigh 

 about 2 lb. each. They thrive in a warm and moderately 

 damp summer and dry, hot autumn. A deep, medium loam 

 with a fair proportion of lime is the soil best suited for their 

 growth. Late nitrogenous manuring should be only sparingly 

 done. The seed is usually sown in rows 14 or 15 inches 

 apart, and the plants are afterwards singled so as to stand 6 

 or 8 inches apart in the rows. The usual yield is from 12 to 

 16 tons per acre. 



Turnips and mangolds are very watery, and in nearly all 

 cases the large roots are much more watery, and therefore less 

 valuable, weight for weight, than the small ones of the same 

 variety. 



The sugar-beet is now a most important crop, especially 

 in Germany, Russia, France, Austria, and the United States. 

 Beet sugar is gradually replacing cane sugar. In 1903-4, for 

 example, it was estimated that the European production of 

 beet sugar amounted to 5,910,000 tons, while the world's 

 production of cane sugar was estimated at 3,535,000 tons. 



Average Composition of Turnips, Swedes, Mangolds, 

 AND Beets. 



The Potato {Solanum tuherosum). — The valued product of 

 this plant is the underground stem, known as a tuber. Usually 

 the crop is grown from the tubers or " sets," 



