370 BOAED OF AGRICULTURE. [Pub. Doc. 



the nitrogen it needs from the air, it must liave the assist- 

 ance of the bacteria which live in nodules (which are about 

 as large as the head of a pin) on its roots. These bacteria 

 can be supplied either by the a})plication of a few hundred 

 pounds per acre of soil from a field where the nodules 

 are found to be abundant on the clover, or b}^ the use of 

 a special culture prepared in the United States Department 

 of Agriculture. It is not believed, however, that it will 

 often be found essential to supply these bacteria. Clover 

 has been so long and so generally grown in this section, 

 that these bacteria are practically everywhere aljundant ; 

 and the nodules will develop upon the roots of clover in 

 practically all situations, provided the conditions essential 

 to the life and activity of the bacteria (which are, in brief, 

 good drainage, thorough tillage and aeration and freedom 

 from free acid) exist. The supply of nitrogen in the air 

 which the clover bacteria under the right conditions bring 

 within the reach of the crop is practically unlimited. It 

 pays, therefore, to make the supply of the elements which 

 clover must take from the soil exceedingly abundant, and 

 among the elements needed potash is one of the most impor- 

 tant. In preparation for clover, it is believed that the 

 application of from 200 to oOO pounds of a high-grade pot- 

 ash salt, or double that quantity of the low-grade sulfate of 

 potash, Avill in most cases be useful. 



If manure is carefully saved and applied in moderate 

 amounts, clover often does well ; but if any considerable 

 proportion of the urine of the manure has been suffered to 

 waste, or if the nianure has been exposed to the leaching 

 action of rainfall, there will be a deficiency of potash, which is 

 found chiefly in the urine, and Avhich, being soluble, is easily 

 washed out. If, then, it be desired to bring land on Avhich 

 manure has been used for previous crops into good condition 

 for producing a hay crop rich in clover, it will usually be 

 best to supplement the manure by means of an application 

 of potash. From 125 to 150 pounds of a high-grade potash 

 salt per acre, applied in connection with manure to the pre- 

 vious crop, will almost invariabl}^ largely increase the pro- 

 portion of clover in the hay crop when the land is seeded. 



