18 CLOVER CULTURE. 



quantity, with the exception of three or perhaps four. These 

 are potash, phosphoric acid, nitrogen and perhaps lime. It 

 is, however, very hard to find a soil so deficient in nitrogen 

 that it will not grow clover. Clover has been grown in ex- 

 perimental pots of pure sand, from which every element of 

 fertility has been washed out, and to which potash and phos- 

 phoric acid in their proper proportions have been added, and 

 the only difference observable between their yield and that of 

 similar plots rich in nitrogen, as well as the other elements, is 

 during the brief period when the nitrogen in the seed has 

 been exhausted and before the action of the microbes in the 

 nodules or tubercles on the roots has been fully established. 

 These experiments, of which we shall hereafter have much 

 to say in detail, show conclusively that clover is less depend- 

 ent on the nitrogen in the soil than almost any other plant, 

 the only other exceptions in fact being other members of the 

 leguminosae, to which order, as we have before said, clover be- 

 longs. 



It will be noticed in the above extract from Weston that 

 clover apparently did best on poor soils, a fact then inexplica- 

 ble but which, it is well understood now, is not due to the 

 poverty of the soil, but to its ability to supply itself with ni- 

 trogen, of which these soils are deficient, from the great source 

 of nitrogen, the atmosphere. It is, therefore, one of the pecul- 

 iarties of tfie clovers and one of their greatest merits, that 

 they are less particular about the first condition of plant life, 

 the fertility of the soil in nitrogen, than any other true grass- 

 es or grains. It is, therefore, almost impossible to find a soil 

 in the Western states so far deficient in nitrogen that it will 

 not grow clover, and it is almost as difficult to find one on our 

 drift soils so far deficient in phosphoric acid, lime or potash. 

 The question, therefore, as to whether the soil is rich enough 

 to grow red and mammoth clover may as well be dismissed. 



In the matter of the mechanical or physical condition of the 

 soil, the red and mammoth clovers are as accommodating as 

 are the other grasses. None of them require the garden cul- 

 ture demanded by most grains. They go on reproducing 

 themselves in the pasture where the plants are allowed to go 

 to seed year after year, and thi sself-seeding in the meadow 

 or the pasture goes on successfully where careful seeding in 

 the well-tilled field often fails. In fact, we have often seen 

 clover sown on the wild prairie, when pastured closely with 

 cattle or sheep, make a perfect stand while it almost com- 

 pletely failed when sown on spring grain, on improved land 



