FERTILIZERS 117 



in dissolved South Carolina and Florida rock and 

 in various bone preparations. These materials 

 are applied at the rate of two hundred to four 

 hundred pounds to the acre. Commercial nitro- 

 gen is chiefly obtained in the form of animal ref- 

 use, as blood and tankage, and in nitrate of soda. 

 It is more likely to be lost by leaching through 

 the land than the mineral substances are, espe- 

 cially if the land lacks humus. Nitrate of soda is 

 very soluble, and should be applied in small quan- 

 tities at intervals. Nitrogen, being the element 

 which is mostly conducive to vegetative growth, 

 tends to delay the season of maturity if applied 

 late in the season. One hundred to three hundred 

 pounds of nitrate of soda may be applied to the 

 acre, but it is ordinarily better to make two or 

 three applications at intervals of three to six 

 weeks. Fertilizing materials may be applied either 

 in fall or spring; but in the case of nitrate of 

 soda, it is usually better not to apply in the fall 

 unless the land has plenty of humus to prevent 

 leaching, or on plants which start very early in 

 the spring. The material is sown broadcast, or it 

 may be scattered lightly in furrows underneath the 

 seeds, and then covered with dirt. If sown broad- 

 cast, it may be applied either after the seeds are 

 sown or before. It is usually better to apply it 

 before, for although the rains carry it down, never- 

 theless the upward movement of water during the 

 dry weather of the summer tends to bring it 



