112 



RESULTS WITH MANGELS 



would have been considerably better. On other plots, the ad- 

 dition of 4 cwt. of common salt to nitrate of soda and super- 

 phosphate increased the crop by 2 tons 8-8 cwts. The con- 

 dition of the mangels receiving sulphate of ammonia also 

 pointed to a deficient supply of ash constituents, as the crop 

 on this plot was generally greener and more leafy at harvest 

 than on the other plots. 



3. Influence of Ammonia salts on Quality. The 

 remarks already made under the head of sugar beet will 

 have indicated much that has to be said in this section. It 

 is impossible to considerably increase a crop of mangels by 

 nitrogenous manuring without to some extent deteriorating 

 the quality of the roots. As the roots become larger they 

 become more watery and more saline, while the percentage of 

 sugar, and of feeding material, diminishes. The deterioration 

 in quality is least when a well-balanced manure is employed, 

 so as to favour the early maturity of the root. Much may also 

 be done by growing the roots near together, so that the final 

 crop may consist of a large number of moderately sized roots, 

 rather than a fewer number of large roots. 



The figures in the following table will give some idea of the 

 effect which the manures employed at Rothamsted have upon 

 the composition of the roots. The percentages of water, ash and 

 nitrogen are the mean of five years' determinations ; the per- 

 centages of sugar are the mean of four years' determinations. 



TABLE XXXVIII. 

 PERCENTAGES OF WATER, ASH, NITROGEN AND SUGAR IN MANGEL 



ROOTS GROWN WITH VARIOUS MANURES AT RoTHAMSTED. 



