vi FOKEWOKD 



his rotation, but how and to what extent the turnips and 

 mangels could be substituted for the more expensive materials 

 then used for milk and pork production. 



A remarkable series of experiments carried out at the 

 Laboratory for Agricultural Besearch, Copenhagen, showed 

 that the despised roots not only increased the production of 

 milk, but that, in general, the dry matter in the roots had the 

 same food value as the same amount of grain. In other words, 

 one pound of grain in the ration of a milk cow could be replaced 

 by such a quantity of roots as contained one pound of dry 

 matter. One of the striking effects of these experiments was 

 to increase the area of root-crops in Denmark from 6000 acres 

 in 1861 to 678,000 acres in 1919. Whereas in former days the 

 root-crop area in Denmark was almost negligible, the percentage 

 of mangels, swedes, and turnips to the total acreage under crops 

 and grass is now 9-7 in Denmark as compared with 5-4 in Great 

 Britain. 



The Danish farmer having learned that the dry matter in 

 the roots which he grew was as effective as the dry matter in 

 his grain crops for producing milk, naturally set himself to 

 find out if the total quantity of dry matter from his turnip 

 fields could be increased. The first movement in that direction 

 was to discover superior strains of seed which would give, in 

 the first place, larger crops. By experimenting and applying 

 the results of the experiments the average yield of mangels 

 increased from 16 tons per acre to 21 tons per acre in a few 

 years. A good cropping strain alone was not enough, however. 

 What was wanted was a strain yielding larger quantities of 

 actual feeding material. It was found, for instance, in one of 

 the experiments, that one strain of mangels producing a very 

 large crop with a low percentage of dry matter actually yielded 

 a smaller quantity of feeding material than a smaller crop grown 

 on the same field but of a superior strain. The bulky crop 

 required the farmer to cart fifty additional loads of water from 

 his field without getting any more feeding material for his stock. 



It was therefore attempted to ascertain the superior strains, 

 those yielding the largest amount of feeding malarial per acre. 

 The book must be read in order to appreciate th; Jngenious and 

 successful method by which those strains were discovered and 



