264 SOILS AND FERTILIZERS 



MISCELLANEOUS CROPS 



314. Flax is very exacting in food requirements and 

 for its culture the soil must be in a high state of fertility. 

 It is a type of weak feeding crop. There are but few 

 roots near the surface and consequently it has restricted 

 power of nitrogen assimilation. 38 Flax should be in- 

 directly manured. Direct applications of stable manure 

 produce poor crops, but when the manure is applied to 

 the preceding crop, excellent results are obtained. Flax 

 does not remove a large amount of fertility, but if 

 grown too frequently the tendency is to get the land out 

 of condition, rather than to exhaust it. The best condi- 

 tions for flax culture require that it should be grown on 

 the same land only once in five years. Flax straw does 

 not form suitable manure for flax lands. Dr. Lugger 

 demonstrated that there are produced, when the roots 

 and straw of flax decay, products which are destructive 

 to succeeding flax crops. 77 Also flax diseases are intro- 

 duced into land by the use of diseased flax seed. The 

 food requirements of flax are met when it follows corn 

 which has been well manured, or a sod which has been 

 given the cultivation described for wheat. Flax and 

 spring wheat are much alike in food requirements. 



315. Potatoes. Potatoes are surface feeders, and 

 when grown continuously upon the same soil without 

 manure, the yield per acre decreases more rapidly than 

 that of any other farm crop. Experiments with pota- 



