THE COMPOSITION OF FEEDING STUFFS 7 



cent; root crops, beet pulp, and wet brewers' grains, 80 to 90 per 

 cent; in case of turnips and some vegetables, as pumpkins, the 

 water content may reach even 93 to 95 per cent (Fig. 1). 



A knowledge of the amount of water in a feeding stuff is im- 

 portant, both because its value for the nutrition of farm animals 

 is largely dependent thereon and because its keeping quality is af- 

 fected thereby. A high water content renders plant materials liable 

 to decomposition through the growth of bacteria and molds. 



Water is the vehicle by which nutrients in both plants and ani- 

 mals are transported from one part to another. Plants absorb it 

 from the soil through their roots, and with it take up mineral 

 matter held in solution in the soil water. The quantity of water 



10 20 30 40 50 60 10 80 90 



100 



Fig. 1. — Water in common feeding stuffs, in per cent. 



thus taken up by plants is very large, and this is partly retained 

 in the cells and the sap of the plants, and partly again evaporated 

 through the leaves. For every pound of dry substance in the plant 

 it has been found that about 400 pounds of water are required, on 

 the average, the exact figure varying from below 300 to over 1000 

 pounds, according to the character of the soil and the crop. 



Dry Substance. — The components of the dry substance of 

 plants considered in the following pages are : Mineral matter or ash, 

 protein, fat, nitrogen-free extract, and fiber. 



Mineral matter in plants is derived from the soil through the 

 root system. This is the portion of the plant which remains as 

 ashes after combustion. It is composed of the elements already 

 given and, in addition, of many elements that happen to be present 



