MANURIAL VALUES OF FEEDING STUFFS 



87 



highest manurial values. Where there is a choice between different 

 feeding stuffs, the contents of valuable fertilizer ingredients in the 

 feeds should receive careful consideration. By way of illustration 

 we may bring together in a table some of the common feeding stuffs : 



Fertilizer Ingredients of Some Common Feeds Contained in One Ton 



We note that among the coarse feeds the legumes are richer than 

 the grasses, not only in nitrogen, but also in potash, and slightly 

 so in phosphoric acid. Cotton-seed meal, oil meal, and gluten meal, 

 among the concentrates, are all high in nitrogen, but, unlike the 

 first two, gluten meal is greatly deficient in both phosphoric acid 

 and potash. Corn is very low in all three fertilizer ingredients, 

 and brewers' grains are low in phosphoric acid and potash, especially 

 the latter. Feeds of high fertilizer values should, under otherwise 

 similar conditions, be preferred to those of relatively low fertilizer 

 value if they serve equally well the purpose in view. Corn is, there- 

 fore, other things being equal, worth less to the farmer than is 

 wheat bran, and linseed meal and cotton-seed meal are worth more 

 than either. 



Fertility Retained by Farm Animals. The amounts of the 

 fertilizer ingredients of feeding stuffs retained by farm animals in 

 their bodies or made use of in their products will vary with different 

 animals, and with the same animals at different periods of growth. 

 The following table 2 shows the proportions of nitrogen and ash 

 constituents voided by animals or obtained in animal products, 

 according to the English agricultural scientists, Lawes and Gilbert, 

 of the Rothamsted Experiment Station : 



2 Warington, "Chemistry of the Farm," 21st edition, 1913, p. 214. 



