No. 4.] 



TOBACCO GROWING. 



23 



Next, What have we learned of the food of the crop? 

 What does it take out of the soil ? 



Of course the larger part of the weight of the plant, 

 either in the field or after curing, has been taken out of the 

 air. All the solid matter of the woody tissue, the starch, 

 sugar, gum, fat, wax, green coloring matter and the larger 

 part of the nicotine and protein, too, come, not from the 

 mineral matters of the soil or the fertilizers, but from the 

 air, and, we believe, are always there in sufficient quantity 

 to meet all the demands of any crop. Mineral matters and 

 nitrogen make up only 25 or 30 per cent even of the air- 

 dry cured leaves, and, of course, in the green plant the 

 proportion is very much smaller. But these mineral ele- 

 ments are as essential to life and growth as those other 

 things which make up most of the weight of the crop. 



A tobacco plant can no more live without potash, for in- 

 stance, than without sunlight or water. 



What, then, are these mineral elements, and how much 

 of them does an average crop take out of the soil. 



At our usual distance of planting (rows 3 1-2 feet apart, 

 18 inches in the row) we get something more than 8,000 

 plants on an acre. A good crop is 1,875 pounds of pole- 

 cured leaves. The stalks, at stripping time, will weigh 

 about 3,200 pounds. 



If the soil has been for years well dressed with fertilizers, 

 we may figure on the following quantities of nitrogen and 

 mineral matters in this crop : — 



Qucuitities of Nitrogen and Mineral Matters in a Crop of Tobacco. 



