176 Agricultural Chemistry. 



method of analysis, this will be far from true in the case of hays 

 and straws. Considerable amounts of chlorophyll will contam- 

 inate the "crude fats" determined for the hay crops. The high 

 yield of ether extract in alfalfa hay, as in the case of other con- 

 stituents of this crop, is incident to a large total yield of dry 

 matter obtained from the several successive cuttings per season. 

 In this respect, this crop possesses a marked advantage in com- 

 parison with the others. 



A large proportion of the ash of cereal straws, some of the 

 cereal grains, and the common hays, consists of non-essential 

 silica. The legumes and root-crops in general, however, are very 

 low in this constituent. The excessive ash content of alfalfa, the 

 mangel, the cabbage and other crops is notable ; being composed 

 chiefly of such essential constituents as lime, potash, and phos- 

 phoric acid, it has a significant bearing upon the well-known ex- 

 haustive effects of these crops upon the soil, f A knowledge of the 

 amount and composition of the ash of crops gives a basis for the 

 selection of animal rations, well-balanced in ash constituents. ) 



The relative drain of some crops upon the soil is shown by tne 

 table in the appendix quoted from Warington. The figures 

 i'l-i- sulphur trioxide have been corrected in most cases on 

 the basis of determinations made at the Wisconsin Experiment 

 Station. The older determinations of sulphur by analysis of 

 the ash have been shown to be low. Other data have been com- 

 piled from various sources and added to Warington 's table. 



The food requirements of cereal grains, as shown by a general 

 survey of the table, are not widely variant. It will be observed 

 that the ash constituents are uniformly much higher in the straw 

 than in the grain. Nitrogen, on the other hand, accumulates 

 chiefly in the grain, about two-thirds of the total nitrogen re- 

 moved being found in this part of the crop. The separate con- 

 stituents of the ash show great differences in their relative dis- 

 tribution between grain and straw. Thus, while potash, soda, 

 lime, chlorine and silica are located chiefly in the straw, the 

 greater part of the phosphoric acid occurs without exception in 



