PROFITABLE MANURING. IJ 



izer chemicals, should contain such quantities of potash, 

 phosphoric acid and nitrogen, that, as nearly as may be, 

 all of each is taken up by the crop. A manure or fertilizer 

 thus proportioned is said to be well balanced. 



In the figures referred to in the earlier part of this 

 chapter, an illustration is given of an attempt to grow plants 

 without nitrogen, and, through the use of pictures taken 

 from actual photographs, it was shown that, except in the 

 case of the class of plants called legumes, plants cannot 

 make any useful growth without nitrogen. Had Prof. 

 Wagner withheld either potash or phosphoric acid, no con- 

 siderable growth would have been made in the case of either 

 the barley or the legumes. The illustration was made, 

 however, not to show that any crop or crops can do without 

 one or another of the elements of plant food, but to show 

 that a certain class of plants can supply their own nitrogen. 

 Legumes must have nitrogen as well as other plants, but do 

 not need much nitrogen manuring. This one point is the 

 basis of the most important detail of profitable manuring. 



Manuring, as already stated, means the use of potash, 

 phosphoric acid and nitrogen in growing a crop. Profitable 

 manuring includes the selling of the crop for an increase 

 over the cost of the manure, cost of seeding, tillage, and 

 other necessary expenses Thus plant food may be 

 regarded as something which is bought to grow crops and 

 sold as crops to repay for the investment. Therefore* the 

 potash, phosphoric acid and nitrogen converted into crops 

 should always be sold at a much higher price than they cost 



