60 AGRICULTURE. [cH. 



produce of the land leads to an increase in the quan- 

 tity of manure, and this finds its way back to the land. 

 If, however, the lime be allowed to work out the 

 organic matter in the soil, and no proper return be 

 made to the land, then the land suffers very seriously. 

 Hence it may be taken as a rule, to which there are 

 very few exceptions, that the larger the quantity of 

 lime that is used, the more farm-yard manure should 

 also be supplied. The successful cultivation of the 

 land is throughout a well-balanced system, and any 

 departure from an equal-handed course of procedure 

 will soon show itself by the decreasing produce of 

 the land. 



1 1 6. It was at one time the general practice for 

 lime and farm-yard manure to be used at or about 

 the same time. The practice was, however, loudly 

 condemned in the early days of agricultural chemistry, 

 for it was shown that if lime were added to farm-yard 

 manure, its ammonia would be scattered into the 

 atmosphere, and it was thereby practically lost. Here 

 was an instance of the misapplication of a truth, from 

 overlooking the controlling influence consequent upon 

 this action taking place in the soil. We have 

 already seen (107) that the action of caustic lime 

 upon a mixture of farm-yard manure and soil produces 

 a most valuable fertilizer, instead of causing a loss of 

 ammonia. To avoid all possibility of danger, these 

 manures should be added to the soil at different times. 

 The farm-yard manure should be ploughed into the 

 soil in the first instance, and the lime may then be 

 spread on the surface and harrowed into the land. 



117. The land in many cases receives its supplies 

 of lime in a less powerful form, viz., in the various 

 forms of carbonate of lime. Chalk, marl, and 

 shell sand, are instances of this kind. The practice 

 of applying chalk to the land has very generally a 

 two-fold object in view. It adds to the land a supply 

 of lime, and if it be freely applied it also alters the 



