146 CLOVER CULTURE. 



action, and are covered by the great northern drift in which 

 the elements derived originally from the primary rocks are so 

 thoroughly commingled that it is difficult to find a soil desti- 

 tute of the two great inorganic elements of fertility, potash 

 and phosphoric acid. Hence, the important question with 

 him is how to obtain a supply of nitrog-en commensurate with 

 the supply of potash and phosphoric acid in the soil. He 

 has another very great advantage. His soils are not, except 

 in rare cases, so far exhausted by long cultivation of their 

 potash and phosporic acid that they refuse to grow the 

 clovers. They are not, therefore, said to be "clover sick." 

 He can proceed to draw on them at once to the limit of their 

 supply in nitrogen, because he can count with confidence on 

 ;an abundance of potash and phosphoric acid which are so 

 essential to the growth of clover. He has still a third 

 advantage, viz : That while many eastern soils heave out 

 the clover during the late winter and spring months by purely 

 mechanical action, his soil, when properly drained, holds the 

 clover plant during the entire period of its natural life. 



If, however, he postpones the use of clover and other 

 legumes until his soil is exhausted of its natural supply of 

 potash and phosphoric acid by continuous cropping with the 

 cereals and grasses that are wholly dependent upon soil nitro- 

 gen, his condition will be practically hopeless. He cannot 

 purchase commercial fertilizers of any kind at present prices 

 at the sea-board, paying in addition freights and profits, and 

 then pay freights and profits on his products back to the 

 principal markets. When this exhaustion has taken place it 

 is too late to grow the legumes, for these are as dependent on 

 potash and phosphoric acid as are the cereals on nitrogen. 

 When his soil is thus reduced to the condition of some of the 

 soils of the eastern states, he may as well give up the 

 struggle. 



The fact, attested by the experience of clover growers in 

 many thousands of cases, that a good crop of clover roots 

 adds to the ordinary crop from fifteen to thirty bushels of 

 corn per acre the first year, and almost an equal amount the 

 second, and to all other crops in a corresponding proportion, 

 should teach the western farmer that his soil needs mainly 

 nitrogen, or, rather, that his soil is more deficient in nitrogen 

 than in either potash or phosphoric acid. The best way 

 agricultural chemists have found of analyzing a soil is to 

 interrogate it with various commercial fertilizers, and find 

 from the varying yield, what great element of fertility is 

 lacking. The farmer interrogates his separate fields in the 

 same way, when, side by side with a crop grown on clover 



