268 FERTILIZERS. 



which the crop is to be grown. Shell fish, as clams, scollops and muscles, though not equal to 

 alewives and herring for manures, are still very valuable. 



12. Fertilizers from the Farm-Yard. 



These are not so purely animal as the preceding ; they consist of animal matters, intermixed 

 more or less with fine fodder, changed in various degrees by the organs of digestion. The 

 value of all these products is variable ; it depends entirely upon the food : rich food gives an 

 active fertilizer. The excrements of geese fed upon grass is less valuable than if they are fed 

 upon corn. Cattle receiving a quantity of corn meal or oil cake, will furnish a manure far 

 more active than when fed on hay. Those fertilizers are all bulky and heavy, and their use 

 is commonly confined to the premises upon which they are produced ; their bulk, however, 

 serves an important end, it operates mechanically, and promotes a loose, friable condition of 

 the soil and the pentration of air. 



The application of farm-yard manures is well understood : they have been, and always will 

 be, the great sources from whence the farmer will derive his fertilizers ; they have few contin- 

 gencies in their application. If the season is dry their presence in the soil becomes a source 

 of moisture, and a well manured field is more independent of rain than when manured with 

 richer kinds, as guano. The proper preservation of manures of this description is well un- 

 derstood, though it is not always acted upon. The crops to which they may be directly ap- 

 plied are well determined, and the most profitable quantity, though there are fewer restrictions 

 than in the case of the active and energetic manures. There is one point necessary to be at- 

 tended to ; the manure heap should be under cover, and it should never stand through the 

 summer to ferment and burn out. Much of these matters, in cities, where they accumulate in 

 close boxes, are injured, especially the excrements of horses. Another practice should be 

 avoided here ; quicklime should not be put into the heaps, but gypsum ; with the former am- 

 monia will be lost. The improved system of building barns and out-houses, together with the 

 enclosures, is doing much to save the valuable parts of fertilizers. The more common and free 

 use of gypsum in stables, yards and all places where volatile substances are escaping, seems 

 very desirable, and even necessary, in order to save the nitrogenous matters, so essential to the 

 perfection of seeds and grain. Plaster is preferable to sulphuric acid, which is often recom- 

 mended, being less expensive and less liable to create accidents by spilling. 



The ash of the excrements of the horse has the following composition : 



Silica, 3-20 



Phosphate of lime, 0-40 



Carbonate of lime 1 • 50 



Phosphate of magnesia and soda, 2-90 



8 - 00 Jackson. 



