256 SOILS AND PLANT LIFE ' 



be placed in the ground by the farmer before the legume 

 can be successfully grown. This is known as inoculation. 



192. How the Nurse Crop may affect Clovers. — We 

 should keep in mind the fact that clovers are commonly 

 sown in the rotation with a small grain, after the removal 

 of which they take possession of the ground as stated in 

 Section 140. This nurse crop of small grain is not, as its 

 name might be taken to indicate, a help to the young 

 clover plants, but is often very much a hindrance instead. 



While there are many good reasons for this practice, 

 it is still true that it is open to some serious objections. 



Thus we have found that the small grains, which are 

 shallow-rooted, demand a seed bed that is firm and com- 

 pact save near the surface. This is not true of the clovers 

 generally, since, owing to their long tap roots, a seed bed 

 that is loose and mellow to considerable depth is better 

 suited to their needs. 



Aside from this, it is known that if oats are used as a 

 nurse crop, as is frequently the case, they almost com- 

 pletely exclude the sunlight from the young clover plants, 

 making healthy, vigorous growth impossible, and moreover 

 they take nearly all the moisture and available plant 

 food from the seed bed. It follows that when the nurse 

 crop is finally harvested and the delicate plants, which 

 have made top growth at the expense of root growth, are 

 suddenly exposed, without a proper supply of moisture, 

 to the direct rays of the hot midsummer sun, they must 

 suffer severely if, indeed, they do not succumb. 



The same result must follow in case any other small 

 grain is used as a nurse crop if the stand is too dense. 



193. How the Method of Seeding may affect Clovers. — 

 It is a rather common practice to sow clover seed on the 

 surface of the ground and to harrow or to disc it in. 



