IMPROVED STEAINS OF BOOTS 43 



To estimate the amount of solids or dry matter in root pulp 

 presents some difficulties, because the sugar is very easily 

 decomposed when heated. It is, therefore, necessary to dry 

 the sample at a lower temperature than usual in chemical 

 analysis. Experiments by Prof. V. Storch, 1 E. K. Kristensen, 

 and others have proved that all the water can be evaporated 

 by drying at 85 C. (185 F.), that even at somewhat lower 

 temperatures a true estimation of the dry matter can be made 

 when drying a sufficiently long time or drying in vacuum, but 

 that heating to temperatures above 85 C. causes a decomposi- 

 tion of the sugars, and more so in swedes than in mangels, 

 noticeable by a brown colouration and a loss of weight beyond 

 that due to the evaporation of the water. 



After this description of the technique of these Comparative 

 Cultivations as now practised we will revert to a consideration 

 of the result of the work during the years from 1889 to 1899 

 inclusive. 2 The comparison was between the best strains only 

 of each variety. At that time it was found that Barres (a 

 yellow intermediate) was the best of the varieties of mangels 

 grown in Denmark from Danish seed, Yellow Tankard the best 

 of turnips, while Bronze Top or Bangholm were as good as any 

 of the swedes, and Champion the best of carrots. These were 

 also the kinds of roots most generally grown, and it is probable 

 that this fact had a bearing on the result. 



A comparison of varieties is, however, of limited value, in- 

 asmuch as the differences between various strains within a 

 variety are often greater than the differences between the 

 varieties. The chief and the most important result of these years' 

 competitions was indeed to prove that the question : Which 

 variety of roots shall be grown ? is of very little importance 

 compared to the question : Which strain shall I grow ? 

 Measured in price of corn, and taking 1 Ib. of total solids of roots 

 to be equal to 1 Ib. of com, as demonstrated by Fjord's feeding 

 experiments with cows, it had been found that there could be 

 a difference of 2 to 4 per acre in the values of the root crops 

 when growing various strains of the same variety. This 



1 V. Storch, 58th Report from the Laboratory for Agricultural Research, 

 1905. 



2 Helweg's Report in Tidsskrift for Landbrugets Planteavl, 7 vol., 

 K0bennavn, 1901, p. 191. 



