FOOD OF PLANTS. 121 



relation which ought to exist between the surface cultivated in 

 forage, and that devoted to the cultivation of merchantable pro- 

 duce. Each year they will export grain, cheese, and some ani- 

 mals. Thus there will be a constant export of azotic products, 

 without any importation of similar matter, and during all this 

 time the fertility of the soil is not impaired. The organic ma- 

 terial constantly exported will be replaced by the culture of 

 ameliorating plants or by fallowing ; and the art of agriculture 

 consists in adopting the rotation which best favors the most 

 prompt transition of the elements of the atmosphere into the 

 soil. 



221 • The above is a true representation of the course pur- 

 sued on numerous farms, where there is a constant exportation 

 of products, but no importation of manure, and yet the farms 

 are increasing in richness ; but it is a lamentable fact that the 

 soil of many other farms which export no more, by carelessness 

 and mismanagement, is becoming exhausted. The latter class 

 of farmers are inflicting serious injury on posterity, as it will re- 

 quire a long series of years to bring back an exhausted planta- 

 tion to a state of fertility, although it requires but little proper 

 management to keep a good plantation good for ages. 



222. Raspaii remarks that, "for the reason that a plant 

 would die in a vacuum, for the same reason would it die in a 

 soil destitute of the bases which were necessary for its organic 

 constitution. This would be asphyxia for want of soil, as the 

 other is asphyxia for want of air ; for to live is to combine, and 

 without elements no combination would be possible." But in 

 most soils all the necessary elements are found in a greater or 

 less degree. To these facts the eye of the agriculturist should 

 be open, and the constitution of his soil should be known, that 

 be may be enabled, as much as is in his power, to supply the 

 deficient element necessary for the crop he wishes to produce. 

 It is a common complaint in almost every section of country 

 that some plants uniformly degenerate. In some places it will 

 be one kind, in others another. Raspaii has shown that al- 

 though a soil might be rich in every other respect, but not con- 

 taining the necessary salt for the particular species, the plant 

 uniformly degenerates, and finally ceases to produce seed. The 

 gardener, being aware of this fact, should make such application 

 as the general nature of his soil seems to indicate. 



221. What is a lamentable fact ?— 222. What does Eafepail say 1 How is 

 it in most soils? What should the agriculturist know What is said in 

 rogard to some plants and their seed ? 



6 



