DIVISION OF CHEMISTRY 237 



SESSIONAL PAPER No. 16 



THE EELATIVE VALUE OF FIELD ROOTS. 



MANGELS. 



Farmers in making selection of the variety of field roots to sow, usually take 

 into consideration yield and keeping quality in storage, but neglect to acquaint them- 

 selves with the relative feeding properties of the different varieties offered for sale. 

 This latter is an important point, especially as regards mangels, the chief root crop 

 in many sections. Our investigation, carried on season by season for the past" eight 

 years, has shown wide differences in dry matter and sugar-content between the 

 varieties examined — differences in some cases amounting to almost 100 per cent. It 

 is not claimed that the whole value of mangels in the ration is determined by their 

 nutritive properties as measured by the percentage of their nutrients. Undoubtedly 

 their succulency, their palatability, their entire digestibility, in addition to their 

 medicinal properties, give them an enhanced value in the well-balanced ration. 

 Nevertheless, since all varieties contribute alike in these respects, we may safely con- 

 clude that those possessing high percentages of the nutrients will be more valuable as 

 food than varieties less rich. It is this consideration that leads us to direct the 

 attention of the farmer to the results of 1912, presented in the following table. 



Twenty-three varieties of mangels, grown on the Central Experimental Farm, 

 Ottawa, were submitted to analysis. The larger number of these are well-known 

 mangels and have appeared in the series for a number of years. It is not claimed 

 that these are all distinct varieties or sorts; seedsmen are apt to rename for the pur- 

 poses of advertisement, old and well-known strains, and this has led, no doubt, in 

 some cases to duplication of the same variety in the series. Unfortunately, there 

 is no way of eliminating this duplication, nor indeed of recognizing it, with certainty, 

 when it does occur. We do know that in some cases, though it is not admitted by 

 seedsmen, the same variety is put out under two or more names, and this necessarily 

 has led to confusion in a critical study of our data. It is quite possible, of course, 

 for these to be an improved strain of an old and well-known variety, and giving such 

 a distinct name has some justification. 



In the table that follows, the varieties have been placed in the order of their 

 richness in dry matter. In a general way, but not universally, the sugar-content 

 bears a relation to the dry matter. As sugar is the most important nutrient in this 

 class of foods, its percentage has been determined and recorded in the table. The 

 average weight of root, which, as a rule, bears a fairly constant ratio to the yield per 

 acre, is also given. 



