If the deficiency of potash is very marked, the leaves be- 

 come narrow and. the plants are especially susceptible to the 

 bacterial disease which manifests itself by curiously 

 crumpled, small leaves and by dark rings in the root. This 

 disease is quite common in American beet fields. But since 

 most of the diseased beets have lost their tops before har- 

 vest, it is frequently overlooked. A diseased beet, which 

 still retains its top, seldom contains over 10 per cent of sugar. 



Sources of the Plant Food 



If barnyard manure is to be used to supply nitrogen to 

 the beet, experience has shown that it should be applied from 

 six months to a year before the beets are planted. 



Where manure, or, green crops are plowed under at the 

 time the beets are planted, there is an excessive growth of 

 leaf and the beets are so late in maturing that the sugar 

 content is seriously reduced. 



On the other hand, if nitrate of soda is used it may be ap- 

 plied after the beets are growing, provided the quantity be 

 not too great. 



As a source of phosphoric acid, acid phosphate, dissolved 

 bone black, and acidulated bone are suitable and basic slag 

 is good where it can be obtained. The excess of lime in the 

 slag may be of benefit on some soils, for the beet contains 

 considerable lime. If bone is used it should be as finely 

 ground as possible, but it acts rather too slowly. 



Not only is potash the most abundant plant food in the 

 beet, but it has a special work to perform in connection with 



15 



