No. 6. DEPARTMENT OF AGRICULTURE. 475 



The turnip also possesses characteristics of value, owing to its 

 rapid appropriation of food in cool weather and consequent large 

 growth during the late fall. These varieties which root deeply are 

 preferable, because they gather a portion of their food from lower 

 layers of soil and store it in their enlarged bulbous roots, near the 

 surface; besides this peculiarity, the growth of the crop is an impor- 

 lant factor, as it exerts a favorable influence upon the physical char- 

 acter of the soil. It causes a separation of the soil particles and 

 permits a freer access of air. The disadvantages of the crop is that 

 it dies at the beginning of winter. Still, if a considerable crop is 

 grown, the mulch, consisting of roots and leaves, will hold the soil 

 together, besides preventing as rapid a leaching as if the soil were 

 entirely exposed. 



Dwarf Essex rape is another plant that may be grown as a cover 

 in the late fall and to serve as a mulch during the winter, and for 

 these objects serves an admirable purpose, though possessing the 

 disadvantages mentioned for the turnip. 



All of the crops here mentioned may be made virtually catch 

 crops and thus not interfering with a regular rotation, and even if 

 pastured or completely removed they leave the soil in a better con- 

 dition than if no crop had been grown; the soil is improved, because 

 its functions have been exercised and at a minimum expense. 



Catch Crops, ''Nitrogen Gatherers.'" 



Of the "nitrogen gatherers," the clovers as a class are perhaps 

 the best known, though it is believed that a brief description of the 

 characteristics of the various useful plants belonging to this group 

 will be helpful. 



Red Clover. 



The renovating character of a crop of red clover is well known, 

 and even when only the stubble and roots are the source of the 

 additions made to the soil, the improvement which follows is very 

 marked. Farmers know that corn or wheat seeded on a clover sod 

 will do much better than when seeded on raw ground or on sod from 

 grasses. It is ordinarily a biennial though sometimes the life will 

 continue through three seasons. Its characteristics are such as 

 to make it adapted to a wide range of soils and of climatic condi- 

 tions, though it thrives best on good soils, well supplied with humus. 

 It is liable to be uprooted on wet soils by the alternate freezing 

 and thawing in spring, and to be destroyed by hot weather on light 

 sandy soils. The amount of seed to be used when the purpose is 

 to secure the largest crop of clover is about 12 to 16 pounds per 

 acre, depending on the character of the soil, the better the soil the 

 les« the amount of seed required. 



