44 



THE CANADIAN HORTICULTURIST. 



fixed by thousands of scientific experiments, 

 that plant food is not merely manure, or fer- 

 tilizer, or fertilizer chemicals even, but the 

 nitrogen, potash, and phosphoric acid con- 

 tained in these substances. This is the first 

 idea to fix thoroug-hly in the mind, and a 

 g^reat deal has been gained when so much is 

 accomplished. Next should be considered 

 the feeding- habits of plants, and these are 

 shown largely by the chemical analysis of 

 the whole plant substance of any crop, grain 

 or forage, including in every case the roots, 

 stubble and straw — all such parts as are 

 commonly considered useless as having no 

 sale value. It is well to look into these re- 

 fuse portions of crops still more closely. 

 While straw, roots and stubble have little 

 crop value in the market, they take up their 

 proportionate amount of the plant food 

 needed for the crop ; but, without these 

 comparatively useless proportions the val- 

 uable grain or forage as the case may be, 

 cannot be realized. Hence, the plant food 

 required for a certain crop must always in- 

 clude an allowance for the elements contain- 

 ed in the comparatively useless stubble, roots 

 and straw. 



The feeding habits of the chief grain crops 

 are shown roughly by the following table, 

 giving the actual plant food required for 

 crops as indicated : 



Bu. per acre Nitrogen Potash Phos. Acid 



Wheat 35 60 lbs. 35 lbs. 25 lbs. 



Rye 30 52 " 47 " 27 " 



Barley 40 47 " 39 " 22 " 



Oats 60 56 " 65 " 23 '• 



It is imperative, in order to realize the 

 yields as above, that the crops should have 

 in available form the quantities of nitrogen, 

 potash and phosphoric acid given in the 



table. It is also well known that crops can- 

 not sweep a soil clean of food, and that all 

 plant food elements must be present in ex- 

 cess of the actual requirement of the crop. 

 Knowing this, the farmer can easily balance 

 his plant food to fit the crop. 



Unfortunately, there is a tendency among 

 farmers to use incomplete fertilizers (fertil- 

 izers not containing all three of the essential 

 elements of plant food), and to these we 

 must say that the laws of plant growth are 

 inflexible ; no one element of plant food can 

 replace another. If any two are present in 

 ample quantities, or even in excess, and one 

 element deficient, the crop is limited by the 

 deficient element, the excess of the other 

 two elements goes largely to waste. In this 

 connection, farmers will do well to scan the 

 composition of the fertilizers offered by deal- 

 ers, to see if they are not practically incom- 

 plete in the sense that one or more elements 

 are present only in very small precentages. 

 Where incomplete fertilizers are used to 

 grow a legume (plants of the clover type), 

 the procedure is rational, as the object is to 

 favor a heavy growth of the legume, which 

 type of plant not only takes up atmospheric 

 nitrogen for its own uses, but also stores up 

 large quantities in roots and stubble which 

 may be used as plant food for succeeding 

 crops. In this case, potash and phosphates 

 must be used liberally, as the nitrogen can- 

 not be assimilated unless certain quantities 

 of potash and phosphates are present to 

 accompany same in the vegetable substance 

 of the crop. It must be kept in mind, how- 

 ever, that fertilizers for this purpose may be 

 deficient in nitrogen only. 



S. P. Cox. 





