xii. CHOPS 247 



predominating. The " other N-free extractives " include pectins, pento- 

 sans and cellulose. 



Turnips are not so hardy as swedes, have rougher leaves of 

 greener colour, which are attached directly to the root and generally 

 have roots with white, sometimes yellow flesh. They contain more water 

 than swedes. 



The Swede resembles the turnip in general characters but has 

 bluer leaves, attached to a distinct "neck ". 



There are many varieties, differing in colour, appearance, size and 

 composition. 



Konig gives as the average composition 



Water. Protein. Fat. Sugar. Other N-free extract. Fibre. Ash. 



88-88 1-39 0-18 3-02 4-35 1-44 0-74 



In Scotland and the north of England, swedes (and turnips) are 

 richer in solid matter, especially sugar, than the same varieties grown 

 in the south. 



The upper half of a root is richer in solid matter than the lower. 



In 1904, 1 five varieties of swedes were grown simultaneously in 

 Cambridgeshire (1 centre), Norfolk (2 centres) and Eoss-shire (4 

 centres), and the resulting crops were examined for sugar content. 



The mean values were : Cambridgeshire (5 crops) 6-2 per cent, Nor- 

 folk (10 crops) 6-7 per cent, Eoss-shire (20 crops) 7'2 per cent of sugar 

 in the roots. 



The effect of season is very gi-eat. Thus in 1900, Collins found an 

 average of 6 '26 per cent of sugar in twelve varieties of swedes, while in 

 1901, the same varieties yielded an average of only 4*05 per cent sugar. 

 The effect of manuring is great so far as the yield is concerned but 

 only small in its influence on the composition of the crop (unless 

 through altering the average size of the roots). In all cases, large 

 roots, produced by liberal manuring, are more watery, poorer in 

 sugar, less nutritious, keep worse, and contain a larger proportion of 

 their nitrogen in the non-proteid form, than small ones. Turnips and 

 swedes depend chiefly upon the surface soil and have only limited 

 powers of attacking the insoluble phosphates, though they are gener- 

 ally able to supply themselves with potash. Phosphatic manures, 

 especially superphosphates, and nitrogenous manures, nitrate of soda, 

 or sulphate of ammonia, are usually most effective. 



Mangolds and Beets are deeper rooted and better equipped for 

 supplying themselves with food. The supply of nitrogen is often the 

 limiting factor in determining the crop. Being rich in ash constituents 

 and heavy croppers often yielding twenty-five to thirty tons per 

 acre they are probably the most exhausting crop grown. They do 

 best in warm, fairly dry climates and in deep, somewhat tenacious 

 soils. Many varieties have been obtained by careful selection. 

 Mangolds (the anglicised form of Mangel-wurzel) or field-beets may be 

 divided into long, tankard and globe forms, of each of which there are 

 many varieties. 



1 Cambridge Univ. Dept. of Agric., Guide to Expts., 1906. 



