50 



SUCCESSFUL FARMING 



add plant food to the soil, their absence increases the growth of crops, 

 which means the same thing. 



Cover-Crops Prevent Loss of Fertility. Cover- or catch-crops may 

 be grown greatly to the benefit of the soil. Cover-crops consist of any 

 suitable plants occupying the soil when the money crop is not in pos- 

 session. They make growth during the cool season of the year, take up 

 plant food as it is made available, and hold it in plant form, where it may 

 be returned to the soil when such a crop is plowed under. In this way 



it prevents the loss of 

 soil fertility by direct 

 soil leaching and con- 

 verts mineral plant 

 food into an organic 

 form which upon decay 

 is more readily avail- 

 able than it previously 

 was. Such a crop also 

 adds organic matter to 

 the soil, increasing its 

 power for holding water 

 and being generally 

 beneficial. Good ex- 

 amples of cover-crops 

 are crimson clover or a 

 mixture of rye and 

 winter vetch seeded in 

 corn late in the sum- 

 mer and occupying the 

 soil during the winter. Such crops do not at all interfere with the 

 growth and maturity of the corn. They make most of their growth in the 

 late fall and early spring and may be plowed under in ample time for plant- 

 ing a crop the following year. Such crops are adapted especially to the 

 South, where the winters are mild and freezing of the soil is slight, while 

 erosion and leaching are marked. This practice is quite common with 

 truck farmers, as cover-crops may be seeded after the removal of a truck 

 crop. 



Legumes Increase Soil Nitrogen. Of all the crops instrumental in 

 increasing soil fertility, none equal the legumes, for these alone have the 

 power, through the instrumentality of bacteria residing in the nodules 

 on their roots, to extract free nitrogen from the air. While such crops 

 are richer in protein than the non-legumes, yet at the same time they leave 

 in the roots and stubble a large amount of nitrogen which is available 

 for non-legumes. A crop rotation which does not have at least one 

 leguminous crop every four or five years is decidedly faulty. 



1 Coxirtesy of the Wisconsin Agricultural Experiment Station. 



SOIL FERTILITY BARREL. 1 

 Illustrating the limiting factor in crop production. 



