NORFOLK SOCIETY. 4G3 



The chief object of ploughing may be deemed to be the 

 formation of a seed-bed ; but the particular manner of attain- 

 ing this object must depend on the nature of the soil, and the 

 crop to be cultivated. Hence, to facilitate an understanding 

 of the dili'erent branches of the subject, it will be expedient to 

 consider it under separate heads. 



1. Stiff, or Clay Soils. A general principle applicable to 

 cultivation, is contained in the maxi«i, " Make heavy land 

 lighter, and light land heavier." This may, in fact, be called 

 one of the cardinal rules of farming, because either of the 

 extremes of heaviness, or lightness of soil, is unfavorable to 

 the production of crops. The principal aim then, in the tillage 

 of stiff or heavy soil, should be to make it lighter and more 

 friable. 



But the question is naturally suggested in the outset: — 

 "Why should heavy soil be made lighter ? For several reasons. 

 In the first place, the mechanical relations of such soil are 

 naturally ufavorable to the growth of most crops ; the heavi- 

 ness and compactness prevent the proper extension of the roots 

 of plants, compress them within narrow limits, and of course 

 restrict them to a small supply of food. In the next place, 

 there is a tendency in clay soils to render inert the vegetable 

 nutrition which they contain. It is a common expression, 

 that such soils " hold " manures. They do hold them, — hold 

 them in some instances too closely, — that is, the manures are 

 locked up by some principle which prevents their being fed on 

 by plants. It has been proved by experiments, that clay, or 

 earth in which it is a prominent ingredient, has a strong af- 

 finity for certain properties of manures, as ammonia, potash, 

 soda, &c. The experiments alluded to, consisted in mixing 

 liquid manures, as urine, with various parcels of sand, ordinary 

 loam, and clay. The coloring matter and the odor were ab- 

 stracted from the manures in proportion to the amount of clay 

 contained in the earth. Similar experiments have been tried 

 with night-soil, and with other substances, which in several 

 instances emitted pungent ammoniacal odors. After a thor- 

 ough mixture with aluminous or clayey soil, no smell could 

 be detected. The sandy soil, or that destitute of clay, on the 

 other hand, permitted the free escape of the gases, as proved 



