10 SOILS 



ways plants are contributing to the upbuilding of 

 our agricultural soils. 



The peculiar value of certain plants as soil 

 binders must not be forgotten. One of the most 

 efficient and certainly the most notorious of soil 

 binders is "quack-grass," and its counterparts 

 variously known as "Johnson-grass," "witch- 

 grass," "couch-grass," and other aliases. The 

 evil reputation of this grass is due to the fact that 

 it is extremely difficult to kill, because the long 

 underground stems may root at any point. The 

 smaller the pieces into which the roots are chopped 

 by the irate husbandman, the more widely and 

 thoroughly is the pest scattered. This is just the 

 reason wny "quack" is such an excellent soil 

 binder; the tough, white root -stalks thread the 

 soil in every direction, soon making a network of 

 fibres, which prevent light soils from washing 

 badly. Steep banks or slopes are sometimes held 

 by establishing quack grass upon them ; the under- 

 ground stems are chopped into small pieces and 

 these are sown thickly. Several other grasses, 

 notably Bermuda grass, are particularly service- 

 able in such cases. 



In some sections, notably in Oregon, Eastern 

 Massachusetts and Western Michigan, drifting 

 sands are held by planting them witn sedges or 

 "beachgrass." In Holland the dikes are planted 

 with rushes to bind the soil. Willows ana osiers 

 planted on the banks of turbulent streams are 

 effectual in preventing them from eating away their 

 banks. Morning-glories and related plants are 

 called bind-weeds, because the vines root at the 

 joints and hold the soil tenaciously. A few horse- 

 tails planted in a wet place soon make a dense mat 

 of roots which grasp the soil so firmly that it cannot 



