266 CAUSES OF FERTILITY AND STERILITY [chap. 



hanging round the word lime. However, as will have 

 been gathered from a consideration of the effects of 

 sulphate of ammonia in depleting the Woburn soil of 

 carbonate of lime, the use of artificial manures generally 

 demands an increased rather than a lessened attention 

 to the periodical liming of the land. 



The method of liming which was formerly in vogue 

 consisted in applying very large quantities of quicklime 

 at comparatively long intervals, ioo to 150 bushels 

 per acre ( = 2 to 4 tons) every eight or ten years, or 

 an initial dressing of 100 bushels, with a further dressing 

 of 50 bushels per acre every third year. The reason 

 for this interval lies in the fact that the best effects 

 of lime are to be seen after the lapse of a year or 

 two; the material becomes carbonate, which, being 

 insoluble, is incorporated with the soil and passes into 

 solution as bicarbonate but slowly. The immediate 

 effect of lime may even be a diminution of the crop 

 if it be used on very rich land, or in actual contact with 

 fresh dung ; under these conditions there appears to be 

 some loss of ammonia by volatilisation. Of course the 

 effect of lime is not very persistent, and the dressing 

 must be repeated ; as the farmers say, the " lime sinks in 

 the land," i.e. y carbonate of lime is removed from the 

 surface soil by solution as bicarbonate. 



In carrying out the operation of " liming," the aim 

 should be to ensure as fine a division as possible, so as 

 to incorporate the material intimately with the soil. In 

 some cases the lime is thrown out in heaps on the 

 stubbles in autumn, and slaked by pouring on water, 

 the hot slaked powder into which the quicklime falls 

 being immediately spread over the land. This method 

 only answers with "fat" limes, which slake and fall 

 readily to a dry powder ; a better method is to lay up 

 the quicklime in heaps and cover the heaps with soil ? 



