PLANT FOOD 



^'7 



and of the root tubercles. These root tubercles, with 

 the power of taking nitrogen from the air, are the 

 cause of the direct addition of nitrogen to the soil. 

 The amount of nitrogen that can be added to the soil 

 will depend on the number and size of the root tuber- 

 cles. In other words, it is the object of the clover 

 grower to produce as many root tubercles as possible. 



The second method of seeding clover, i e, in the 

 cornfield at the time of the last cultivation, is often 

 successful and is the source of considerable benefit to 

 the soil where a good growth is secured. The seed 

 is usually sown broadcast and cultivated in when the 

 corn is laid by. A little heavier seeding is desirable 

 at this time, as part of the seed is lost among the 

 leaves of the corn plants, and under ordinary con- 

 ditions of soil moisture at this season of the year, a 

 considerable proportion of the seed will not receive 

 moisture enough for germination. If the season is 

 very dry the seed will not germinate, therefore such a 

 method will prove successful only when there is 

 enough rainfall for germination. 



The third method of seeding, i e, alone, without 

 any nurse crop, is recommended for some sections, 

 such as Wisconsin. In this case the use of the land is 

 usually lost for one year. In most old cultivated fields 

 there is such a supply of weed seeds in the soil that 

 the weeds grow faster than the clover crop. These 

 weeds use up as much soil fertility as a nurse crop 

 without any return. Therefore the nurse crop system 

 is preferred. If the clover is seeded alone, the seedbed 

 should be prepared in the same manner, and seed 

 sown at the same rate as when seeded with a nurse 

 crop. However, in heavy soils it is often best to plow 

 the land and to prepare the seedbed as for corn. 



