CROP CHEMISTRY 



121 



nitrogen-free extract is the largest in amount, although 

 compared to the grain seeds this constituent is smaller; 

 ash, protein, fiber, and fat all being larger in amount. It is 

 the bases in the ash which make the vegetables an important 

 class of foods. 



(b) Leaf Vegetables (Fig. 28).- These do not differ much 

 in composition from the stem vegetables. Stems and leaves 

 have been classed together in the other crops. 



Fig. 28. — Leaf vegetable crop: Cabbages. Horticultural Department, 



Pennsylvania Station. 



(c) Root Vegetables (Fig. 29). — Of these the beets are 

 noted for their sugar content, especially the sugar beet which 

 runs about 15 per cent, sucrose. Potatoes are much the 

 highest in nitrogen-free extract of any of the vegetables, and 

 this is mostlv starch. 



(d) Fruit Vegetables. — As would be expected these run 

 lower in ash than the other vegetables, although on a dry 

 basis this constituent is higher than it is in grain seeds. 

 The ash is largely potash. Crude fiber is less, fat is higher. 



103. Hay. — Stem and leaf crops, or fodder crops as they 

 are customarily called, do not keep well unless cured or 

 preserved in some way. One of the common methods is to 

 make hay out of them. The usual hay crops are timothy and 

 clover, although many other grasses and legumes, par- 



