274 Fertilizers 



a high potential fertility, heavy dressings of the minerals 

 should always be made. A good preparatory fertilizer may 

 consist of 20 pounds of nitrogen, equivalent to 125 pounds 

 of nitrate of soda ; 75 of phosphoric acid, equivalent to 

 600 of acid phosphate ; and 200 of actual potash, equivalent 

 to 400 pounds of muriate of potash to the acre ; and an- 

 nual top-dressings should provide at least 30 pounds of 

 phosphoric acid and 100 of actual potash for the same area. 

 Inasmuch as careful preparation of soil is necessary 

 previous to seeding, and since this can preferably be 

 accomplished by the growth of cultivable crops, the 

 fertilizers may be also partly applied to these rather 

 than all at once immediately preceding the seeding, 

 thus limiting danger of injury to germination by an 

 application of so large a proportion of salts. 



Sweet clover. 



The use of sweet clover is spreading very rapidly in 

 the United States. While its growth and purpose of 

 growth are very much the same as alfalfa, it does not 

 seem to require nearly as much fertilization, and it is not 

 uncommon to produce enormous yields of forage or hay 

 upon good soils without any fertilization. Its culture 

 may be the same as alfalfa, but it has been found more 

 profitable in most localities to sow it in grain in spring 

 when the ground is honeycombed. In this case no fer- 

 tilization is needed. If sown alone, moderate quantities 

 of the minerals should be supplied. It thrives especially 

 well in hard, compact soils, rich in lime. 



Need of lime for legumes. 



Another point that should be remembered in the 

 fertilization of the leguminous plants is their need for 



