552 



Bulletin 317 



This table shows a mean yield of mangels nearly twice as great as 

 that of corn fodder. No account is taken of the food value in the mangel 

 leaves. The cost of a unit of dry matter in mangels is more than twice as 

 great as that in corn. The cost of digestible dry matter in these crops is 

 not shown because only average figures are available for such calculations. 

 Assuming that dry matter in mangels is of more food value than is dry 

 matter in silage corn, there is yet a wide margin between the cost of 

 digestible nutrients in these crops. 



Relation of weather to production of dry matter 



How far the weather influences the production of corn and mangels may 

 be seen from Table 2, in which is shown the relation of rainfall and tem- 

 perature during the growing season to dry -matter production. The pro- 

 duction of dry matter in corn crops seems to conform closely to the varia- 

 tions in temperature and rainfall that occurred during the five months of 

 the com -growing season. Mangels were less dependent on rainfall and 

 temperature than on soil conditions for the production of dry matter. 

 This fact makes the latter more certain as a crop in the variable climate 

 at Ithaca. 



TABLE 2. Temperature and Rainfall Compared with Dry Matter Produced 

 BY Corn and by Mangels for Four Years 



Mean daily temperature (degrees F.). 



Total precipitation (inches) 



Dry matter, pounds per acre (Corn). . 



Mean daily temperature (degrees F.) 



Total precipitation (inches) 



Dry matter, pounds per acre (Mangels)' 



62.0 

 20.30 



May I to September 30 



63-7 

 18.53 



5.755 



Comparative composition of corn and mangels 



The composition of corn fodder and of mangels, as shown in Table 3, 

 accounts for the acknowledged difference in digestibility of the dry matter 

 contained in these two crops. The lower percentage of crude fiber in 

 mangels as compared with com fodder cannot be offset by their greater 

 moisture content, as is almost true of the protein and carbohydrates. 



