140 EXPERIMENTAL FARMS. 



The reaction between the magnesium sulphate and the lime would naturally 

 proceed with time, and succeeding seasons would no doubt show better and bettor 

 results on this treated soil. It would appear, therefore, that soils barren from the 

 presence of this salt, may by the simple method of treatment with lime here sug- 

 gested, be brought into a state of fertility. 



Where a lai'ge portion of the saline matter is sodium sulphate, the treatment 

 with lime would first result in the formation of corrosive soda and then of sodium 

 carbonate. This would finally be converted into sodium sulphate. Although much 

 slower in its action, carbonate of lime would here prove beneficial, since it would 

 render the magnesium salt insoluble without reacting upon the sodium compound. 

 An application of a mixture of gj^psum and lime in such a case might also be of 

 benefit — the former having the tendency to keep the sodium salt as sulphate — the 

 latter converting the magnesium salt into an insoluble form. This treatment should 

 be carried out in conjunction with drainage, which must always be resorted to 

 wherever practicable. For soils impregnated with alkali in which sodium sulphate 

 largely predominates, drainage, deep ploughing, thorough cultivation and high 

 manuring are the only remedies that can now be recommended with confidence. 



MUCK, LEAF-MOULD, PEAT. 



Of all the constituents of plant food taken from the soil by growing crops, there 

 are but three that it is generally necessary to return, viz., nitrogen, phosphoric acid 

 and potash, and repeated experiments the world over have proved that the fertility 

 of the farm soil can only be maintained by such a return. Without it the land 

 becomes, by successive croppings, less and less productive. 



Where mixed farming is in vogue, ordinary well preserved barnyard manure is 

 no doubt the most economical form in which to supply these elements, since by this 

 means nearly 80 per cent of the plant food taken from the soil is replaced. From 

 various causes, however, it often occurs that the supply is inadequate and must be 

 supplemented from outside sources. Leaving out of consideration for the present 

 the question of phosphoric acid and potash, we may discuss briefly the sources from 

 which available nitrogen may be obtained, other than that already mentioned. 

 These fall into three classes : 



1. Artificial Fertilizers, such as nitrate of soda and sulphate of ammonia. 

 These present nitrogen to the rootlets of plants in an exceedingly soluble form. 

 They are, moreover, concentrated fertilizers, since weight for weight they possess a 

 much larger proportion of this element than other nitrogenous manures. Their cost, 

 however, mitigates against their general use and necessitates, for their economical 

 application, a considerable amount of skill and experimenting on the part of the 

 farmer. 



2. Green Manures. — This method consists in ploughing under a growing crop, 

 preferably of clover, pease or some other of the leguminous plants. These plants are 

 known as nitrogen-collectors in contradistinction to others which are nitrogen-con- 

 sumers. They are able to appropriate and assimilate nitrogen from the atmosphere, 

 which when the plants are turned in is preserved in the soil for the growth of 

 succeeding crops. For light sandy soils, poor in organic matter and nitrogen, this 

 method of manuring can be highly recommended. It is economical, since it is both 

 cheap and eftective, improving the tilth and adding to the store of fertility. 



3. Muck, Leaf-mould and Peat. These consist largely of semi-decomposed 

 vegetable matter and contain a considerable, though variable, amount of nitrogen. 

 This nitrogen is not so readily available as in the two classes of nitrogenous manures 

 we have just considered, but by fermentation of the material it may be converted into 

 assimilable forms. The value of a muck or similar material depends chiefly there- 

 fore on its percentage of nitrogen. By a suitable treatment of the air-dried muck 

 or peat, many farmers of Canada may obtain at little cost a manure not only rich in 

 the valuable element nitrogen, but also containing notable quantities of other plant 

 food constituents. All fertile soils possess high percentages of organic matter. This, 



