178 



As already explained, fr)m 50 to 95 per cent of the fertilising con- 

 stituents of food is recovered in the manure, depending upon the kind 

 of animal fed (see p. 176.) 



In order to find from this table the amount of nitrogen, phosphoric 

 acid, and potash which may t>3 expected in manure, it is necessary 

 simply to subtract from the amount of these constituents contained in 

 the food the amount retained in the arfimal body. It can be readily 

 seen that as regards the value of the manure produced the concentrated 

 feeding stuffs, such as meat scrap, cotton-seed meal, linseed meal, and 

 wheat bran stand first ; the leguminous plants, such as red and crimson 

 clover, etc., second; the cereals (wheat, oats, corn, etc.), third, and root 

 crops last. Thus with full-grown aniimls neither gaining nor losing 

 •weight practically all of the fertilising constituents of the food are ob- 

 tained in the manure and each ton of wheat bran, for example, fed would 

 yield manure having a fertilising value of $12.30, each ton of clover hay 

 $7.50, each ton of oats #6.70, and each ton of turnips 96 cents. With 

 growing animals, milch cows, etc., only about 75 per cent of these 

 amounts, or $9.20, §5.60, §5, and 72 cents, respectively, would be obtained 

 in the manure. Finally, with working and fattening animals, which ex- 

 crete about 90 per cent of the fertilising constituents of their food, the 

 corresponding amounts would be $11, $6.75, $6, and 86 cents, respec- 

 tively. 



As the table shows, the amount of nitrogen present in foods is the 

 most important element in determining the value of the manure, since 

 it is the most costly fertilising constituent and is present in much 

 larger proportion, as a rule, than phosphoric acid and potash. The 

 inorganic substances of foods (potash, phosphoric acid, lime, etc.) pass 

 very largely into the manure ; consequently the manure is proportion- 

 ately richer in these constituents than the food. The case is some- 

 what different with the nitrogenous substances, which are partly used 

 in the production of meat, tendon, wool, milk, etc., thus leaving 

 the manure in many cases poorer in nitrogen than the food consumed. 

 Those, however, which are not so used undergo modifications in the 

 process of digestion which render their nitrogen more available to 

 plants. 



As the New York Cornell Station has shown, increasing the amount 

 of nitrogenous matter in the food increases the secretion of urine, thus 

 necessitating the use of more litter and by this means increasing the 

 bulk of the manure produced. The use of nitrogenous foods thus brings 

 about the same result as the use of watery foods. 



INFLUENCE OF THE NATURE AND PROPORTION" OF LITTER. 



Litter is used to furnish a clean and healthful bed for animals, to 

 absorb and retain liquid excrement, to extend manure and render it 

 easier to handle, to increase the physical and in some cases the chemical 

 action of manure, and to check and control decomposition. The 

 materials generally used are not, as a rule, rich in fertilising consti- 

 tuents, as the following table of composition given by Warington will 

 show : 



