MANURES AND FERTILIZERS. 



145 



It is the grand work done for the farmer by agricultural 

 chemistry during the past half century which has ex- 

 plained the causes of the decreased fertility of land due 

 to continuous cropping, and has given the remedies for 

 maintaining the fertility. The latter are as follows: 



First, by selling only such products from the farm as will 

 deprive the soil of the smallest quantities of fertilizing in- 

 gredients, i.e., manufactured products, like milk, cream, 

 butter, meat, eggs, rather than grain crops, hay, etc. The 

 tables given on pp. 148-151 show the amounts of fertilizing 

 ingredients removed in farm products of various kinds and 

 deserve a close study by all farmers. 



Secondly, by carefully saving the manure produced by 

 stock — both liquid and solid (the former by the use of ab- 

 sorbents, peat, land plaster, kainit, superphosphate, shav- 

 ings, etc., or by building special cisterns for storing it; the 

 latter by placing it under shelter, guarding against leakage) 

 — and returning it to the land; as the products sold off the land 

 also contain certain quantities of fertilizing constituents, 

 the loss must be repaired by purchase of concentrated food 

 stuffs, at least three fourths of whose valuable ash ingredi- 

 ents will go into the manure and thus be saved for crops. 



Thirdly, by following a rational system of rotation of 

 crops, and by frequent culture of leguminous crops, — 

 clovers, peas, beans, etc., — since these are able to so fix 

 the free nitrogen of the air as to render it of value to ani- 

 mals and plants. 



APPROXIMATE LOSSES OF FERTILIZING MATE- 

 RIALS IN DIFFERENT SYSTEMS OF FARMING. 



(Snyder.) 



System of Farming. 



All grain-farming 



Mixed grain- and general farming... 

 Mixed potato- and general farming.. 



Stock-farming 



Dairy-farming 



Nitrogen. 



lbs. 

 5600 

 2600 

 2300 



900 

 800 



• Gain. 



Phosphoric 

 Acid. 



lbs. 

 2500 

 1000 

 1000 

 50* 

 75' 



Potash. 



lbs. 

 4200 

 1000 

 2400 

 60 

 85 



