480 



IOWA ACADEMY OF SCIENCE Vol. XXV, 1918 



of hays, due to a considerable extent to the lack of uniformity 

 in the conditions under which curing takes place, so in Table II 

 the various constituents are expressed as percentages of the to- 

 tal dry matter present in the samples of hay analyzed. 



TABLE II. 

 COMPOSITION OF DRY MATTER OF SUDAN GRASS HAY. 



The analysas of Sudan grass hay that have been reported are 

 fairly uniform in all their constituents except protein and ash, 

 which show rather wide variations due perhaps to the conditions 

 under which the crops were grown, and the stage of growth a\ 

 the time of cutting. 



It is generally understood that the majority of crops alter ma- 

 terially in composition as ripening progresses. This change is 

 due not only to the increase in the amount of dry matter and 

 the decrease in the amount of water but also to a variation in the 

 relative proportions of the individual constituents of the dry 

 matter. These changes usually go on until the crop is practically 

 ripe but that this is not so in the later stages of ripening in the 

 case of Sudan grass has been shown by Piper. 



TABLE III. 



COMPOSITION OP DRY MATTER OP SUDAN GRASS HAYSs MADE 



AT VARIOUS STAGES OP RIPENESS. 



*Bul. 194 : Md. Sta. 



^Circ. 125 ; Bur. Plant Ind., U. S. Dept. Ag. 



»Bul. 172 ; Tex. Sta. 



^Bul. 103 ; Okla. Sta. 



»Circ. 125 ; Bur. Plant Ind., U. S. Dept. Ag. 



