HAY. 245 



about 16 %. One hundred tons of grass will yield from 30 to 

 40 tons of hay, while the same weight of freshly cut clover 

 will yield on an average about 33 tons of hay. 



Of great importance is the time of cutting. Since fodder 

 crops are essentially straw, the proper time is before the 

 nutrient ingredients are moved from the foliage into the seed. 

 Hence hay should be cut when the grasses are flowering. If 

 grass is left until too ripe, the resulting hay is found to be 

 poorer in albuminoids and ash, though richer in carbohydrates 

 and indigestible fibre. 



The changes in Timothy grass during ripening are well seen 

 from the following tabled 



It will be seen that the nitrogenous matters are practically 

 not increased by the latter growth, but that carbohydrates and 

 fibre are largely added to after blossoming. On June 26th the 

 grass was in full bloom ; on July 23rd its seeds were almost 

 ripe. 



Grass and clover are always abundantly supplied with micro- 

 organisms, including bacteria, moulds, yeasts, &c. ; these act 

 upon the sap and woody fibre of the grass when cut, producing 

 oxidation and evolving carbon dioxide and small quantities of 

 other gases. The act of oxidation is attended with the evolu- 

 tion of heat. These changes take place in the open air with 

 little rise of temperature, because the heat is carried away by 

 conduction and convection almost as fast as it is evolved. 

 Moreover the activity of the micro-organisms soon diminishes 

 if the materials dry. 



An investigation into the changes produced in grass by fer- 

 mentation was made in 1897 by Emmerling. f Freshly cut 

 grass of the following composition calculated on the dry 

 matter 



* Hunt, Bulletin 5, U.S. Dept. of Agriculture, 

 t Ber. 1897, 1801*; J.C.S. 1897, abst. ii. 579. 



