36 ON THE USE OF LTME, MARL, AND SHELL-SAND. 



It thus appears that in these counties 8 to 10 bushels a year 

 are pretty uniformly applied. On very stiff soils or on peaty 

 land a larger dose no doubt can be used with advantage, but on 

 light soils it is advisable to use it in smaller doses. 



Some farmers prefer using large doses at once, whilst others 

 maintain that repeated dressings with smaller doses are attended 

 with the greatest amount of practical benefit. 



There can be little doubt that, on soils abounding in vegetable 

 matters or wholly destitute of lime, a large quantity will be re- 

 quired at once to change their mechanical and chemical con- 

 stitution ; and the propriety of liming the land heavily at first 

 is thereby indicated. 



But, when land has been brought by cultivation into good 

 condition, the safest plan to maintain it in fertility will be to 

 supply lime at shorter intervals with smaller doses, at the rate 

 of about 8 bushels a year. 



Repeated liming with small doses at larger or shorter intervals, 

 indeed, is necessary to keep the land in its maximum state of 

 productiveness. The reasons for the practice are obvious. 



In the first place, the well-known tendency of lime to sink 

 deeper and deeper into the soil, from year to year, removes the 

 lime from the surface into the subsoil, and thus takes it out of 

 the reach of the roots of plants. This tendency to sink is greater 

 in light and porous soils than in heavy ; but even in very stiff 

 land lime gradually sinks and passes into the subsoil. Hence 

 thejiecessity of applying it as near as possible to the surface. 



Secondly, heavy rains wash it down into the lower strata, and 

 dissolve also considerable portions of it. It is on account of 

 this dissolving action that badly drained soils require to be more 

 frequently limed than those which are well drained. 



In the third place, it will be remembered that all our cultivated 

 crops remove a certain proportion of lime from the soil ; and as 

 some crops take up a much larger quantity than others, the 

 course of cropping must necessarily influence the period at which 

 liming ought to be repeated. 



On the Application of Lime to different kinds of Soils, and the 

 Composition of Soils benefited by Liming. 



It has been noticed already that the efficacy of lime as a 

 fertilizer is influenced greatly by the character of the soil to 

 which it is added ; and as soils vary greatly in their chemical 

 characters, it appeared to me a useful inquiry to ascertain the 

 composition of some soils occurring in the West, upon which 

 lime is usually employed. Mr. Cotterell at Bath very kindly 

 assisted me in this inquiry by procuring for me a good many soils 

 from various parts of Somersetshire and Devonshire. These and 



