The mechanical condition of the soil is another important factor in the cultivation of the sugar-beet. From the closeness of its texture, a stiff clay retains water, and does not readily admit heat or air among its particles; it also opposes much resistance to the fibrous roots making their way through it. By preventing the free growth of the roots downward, clay is especially unfavorable to the sugar-beet crop; for the beet, instead of producing the long, slim root which is necessary for the proper secretion of saccharine material in the sugar-cells, grows round, turnip-like roots, which are of no value for sugar-making. Sand is the opposite of clay, and, from the looseness of its texture, admits heat too freely, and is not capable of retaining a sufficient amount of moisture for the needs of vegetation. In sand, also, the particles of plant food are washed down by the rains below the reach of the roots, or are vaporized by heat and escape into the air. Plants grow best in loam, which is a mixture of these soils of opposite character, in such proportion that the faults of both are corrected. The depth of the soil and the nature of the underlying stratum are also important; for if the richest soil is only seven or eight inches deep, and lies on a cold, wet clay or on rock, it will not be as fruitful as a leaner soil that lies on gravel, for instance, which is perhaps the best subsoil. The best soil for the cultivation of the sugar-beet root is a mellow, sandy loam, with a free and permeable subsoil, such as would be called by the German agriculturist a first-class barley soil. It should be ten to sixteen inches deep—the deeper the better—rich in well decomposed organic matter and minerals.
Ordinary land can not be planted with the same crop year after year without a gradual diminution of product. This is owing to the fact that the specific food of the particular plant is exhausted from the soil by the constant drafts upon it. But if the land is planted one or more years with a vegetable which takes a different kind of nourishment from the soil, time is allowed for the chemical changes constantly going on in the ground to produce a supply of the food required by the first kind of crop. In the cultivation of the beet-root for sugar-producing, it must follow the cereals, such as wheat, rye, and barley, but, to be profitable, not oftener than every third year.
The advantages of correct fertilization in the cultivation of the beet-root are shown by the experiments of Lawes and Gilbert. On one acre of ground, cultivated without manure, 302 bushels of beets were grown. On another acre adjoining and possessing the same characteristics of soil, enriched with 550 pounds of nitrate of soda or Chilian saltpeter, 886 bushels of roots were obtained. The beets grown without manure contained 2,1151 pounds of sugar per acre; the beets grown with the mineral nitrogen con-