Crops. 175 



yields and the yields of proximate constituents of such compara- 

 ble amounts of crops. 



The differences between weights of fresh material and of dry 

 matter in the above table are due almost entirely to water lost 

 in the process of complete curing or drying. For example, corn 

 in the green state consists of nearly 80 per cent of water, potatoes 

 have about the same amount, sugar beets contain about 86 per 

 cent, and mangels consist of over 90 per cent of this constituent. 

 The several hay crops of the preceding table are rather lower in 

 water, containing from 60 to a little over 70 per cent. This 

 amount is greatly reduced by the curing process so that the hays 

 contain only from 10 to 20 per cent. 



The field cured grain crops carry from 7 to 9 per cent of 

 moisture in the straw and about 11 per cent in the seed. The 

 high water content of some of these crops, aside from its detri- 

 mental effect upon keeping qualities, is sometimes of importance 

 with reference to economy of transportation. For example, 

 since the root crops retain most of their original water content 

 during proper storage, it is evident that a given amount of dry 

 food material is handled far less economically in them than in 

 grains and hays. It will be observed that the enormous acre- 

 yields of these crops, particularly of the mangel, are reduced to 

 moderate figures when considered in terms of dry matter. 



The high protein content of the legume hays (clover and al- 

 ifalfa) is in marked contrast to the amount of this group of con- 

 istituents in the common hays and the cereal crops. This differ- 

 ! ence will be discussed in detail in the consideration of individual 

 crops. Mangels also contain a high percentage of " crude pro- 

 tein ;" but it has been shown that more than one-half of the 

 nitrogen upon which this figure is based is not in the form of 

 protein but is contained in amide compounds. This is probably 

 true for other root crops, and greatly diminishes their apparent 

 protein value. 



With reference to the production of fat, it should be stated 

 that while the grains may yield quite pure fats to the chemist's 



