156 DR. SCHLEIDEN'S THEORY OF AGRICULTUKE. 



an inspection of its physical condition and general chemical con- 

 stituents, such as may be made by simple mechanical processes 

 and a slight degree of chemical manipulation, which will give 

 not only a notion of its present worth, but of its future capa- 

 bilities, is almost indispensable. 



C. The object of ploughing, and other allied processes, is the 

 deepening of the soil, the alteration of its texture, either by 

 the mere mechanical action or admixture of organic and inor- 

 ganic manure, and the destruction of noxious weeds, to which 

 may be added the necessity of placing the seed in a fit position 

 for vegetation, and protecting it from birds and other noxious 

 animals. It nmst be borne in mind that, Avhile the opening of 

 the soil subjects it to the influence of the atmosphere more com- 

 pletely and to a greater depth than would be otherwise possible, 

 the humus is rendered liable to rapid decomposition, such as may 

 more than overbalance any good which might arise from the 

 exposure of the surface ; and this destruction takes place at 

 the very time when it is not available for the demands of vege- 

 tation, added to which the most valuable portions are often 

 carried off by an overflow of water. Ploughing, then, must be 

 considered rather as a necessary evil, and one to be employed 

 only so far as necessity requires. Because frequent ploughing is 

 useful in some cases, it is not to be assumed hastily that the rule 

 is generally applicable. 



D. The doctrine of fallows will require a rather more copious 

 abstract. The word was originally applied simply to land wliich 

 was left uncropped, and may be considered exactly opposite to 

 tlie employment of manure. Afterwards the system was some- 

 what complicated by the introduction during the last century of 

 leguminous plants, such as clover, especially from Italy, where 

 the system had long been practised, and fallows, in tlie old sense 

 of the word, have in great measure become obsolete, though 

 it was long retained for matters with which it was originally 

 entirely unconnected. 



We may define it as follows : Fallow is that condition of the 

 land in which, during one or more years, notiiing is taken away 

 in the shape of harvest, or added in that of manure. In this 

 strict sense the grazing of cattle on the fallow-field would be 

 excluded, but, inasmuch as through grazing there is so little in- 

 frino-ement on the proper purport of fallow, it is included under 

 our notion of the word. 



Fallows may be divided into green and naked fallows : in the 

 first the land is suffered to clothe itself with a thick coat of 

 weeds ; in the second it is kept bare by one or more ploughings, so 

 as to be constantly exposed to the influence of the atmosphere. 



1. The thick covering of soil with vegetation hinders in many 

 ways the action of the atmosphere upon it. The shading of the 



