37 



On most farms there are found a greater or less quantity of old 

 rails. These placed lengthwise in the ravines, and held in place by 

 stones thrown over them, often answer a good purpose. 



How to prevent soil washing. This is of infinitely more importance 

 than how to repair damages. It is more than doubtful whether as a 

 people we are in a proper frame of mind to profit by the experience 

 of other nations. It is unfortunately true that we shall probably 

 go through the most costly process of gathering our own knowledge. 



There are several principles involved in presentation of soil wash- 

 ing. It would at first appear impossible 'that tihie hardest, most 

 compact soils are those in which destructive, deep washing occurs. 

 This, however, becomes clear when one remembers that on such sur- 

 faces the water flows on top, with but little to arrest its speed, and 

 consequently with little to diminish its destructive power. On the 

 other hand, if the soil be loose and porous, and especially if it con- 

 tains much vegetable matter, it has a large capacity for absorbing 

 water, which slowly percolates away beneath the surface. The un- 

 derlying principle here, then, is to secure a porous soil, and all the 

 better if that porosity is gained by the roots o-f living plants, which 

 produce also a strong cohesion in the mass of earth. 



When ground much given to washing is plowed for the purpose of 

 cropping, straw is often placed in the furrows, to be covered at the 

 next round of the plow. This is a simple, time-honored method of 

 singular efficiency. 



Underdraining by the removal of surplus water increases the 

 capacity, in times of heavy rainfall, of the soil for absorbing and 

 holding water. This again diminishes, or often almost wholly pre- 

 vents, destructive surface wash. It is well known that soils which 

 are well limed are less apt to wash than those which are not. 



There are times when these methods of preventing soil washing 

 are, alone, wholly ineffectual and must be abandoned or used in con- 

 nection with other methods. Among which are: 



(a) Furrows o-r barriers which run over the field, as nearly as pos- 

 sible, horizontally. This slackens the speed of the water, diminishing 

 its erosive power on the one hand and allowing increased chance of 

 absorption (of the water) on the other hand. 



(b) The formation of terraces, whose sloping surfaces (at least) 

 may be in a dense sod, and whose flat parts may be cultivated or not, 

 as happens. 



(c) Planting belts of trees in the horizontal direction along a hill- 

 side. This allows a chance for the formation of an absorbing layer 

 of humus and of leaves, which will aid the roots in changing the sur- 

 face flow to one of underground character. 



(d) Most important of all giving up to growth of trees all such 

 soil as is likely to wash or to involve considerable expense in pre- 



