COMPOSITION OF LEGUMES AND GRASSES 377 



COMPARISON OF LEGUMES AND GRASSES 



Roots. It is frequently stated that legumes are deeper-rooted 

 plants than the grasses. It is a difficult point to determine, as it is 

 not a simple matter to separate roots from the soil to a depth of sev- 

 eral feet. The character of the soil, age of plants, and other factors 

 so modify the depth and distribution of roots that data taken at 

 different places or at various times are not comparable. 



Data on depth and amount of roots have been taken at Con- 

 necticut, Utah, Arkansas, North Dakota, Kansas, Minnesota, and 

 other places. In general, with both grasses and clovers, from eighty- 

 five to ninety per cent of the roots bv weight have been found in the 

 upper six inches. Alfalfa should be excepted, as it is a very deep- 

 rooted plant. Red clover is also a strong-rooted plant, penetrating 

 from four to six feet, while white clover is "believed to root about one- 

 half as deeply. 



Grasses also vary, brome-grass and orchard-grass penetrating 

 five to six feet in pervious soils; timothy generally three to four 

 feet, blue-grass usually less than three feet. Soils also have a marked 

 effect, the quantity of root being much greater in the subsoil when 

 loose soils are compared with hard, impervious soils. 



Timothy and red clover are very generally grown in mixture, and 

 it is probably true in this case that the red clover has a more 

 abundant root system below the upper twelve inches than the 

 timothy. There is also evidence that as grass sods get old and well 

 matted the roots become quite shallow (see p. 296), while in the case 

 of long-lived legumes the deep tap roots probably increase in size. 



The total amount of root material is of interest as indicating the 

 residue of organic matter left in the soil. Data on red clover and 

 alfalfa, taken at various places, have shown variations ranging from 

 1000 to. 5000 pounds per acre, with most cases nearer the lower figure. 

 The proportion of root to top is usually about 1 : 1.5 or 1:2. The 

 data, however, can not be considered very reliable or constant. 



Composition of Legumes and Grasses. The following table 

 of certain analyses gives a general idea of the relative composition of 

 both the forage and seeds of legume and grass crops : 



