SOIL EROSION 



365 



reversible or hillside plow, by which all of the soil may be turned 

 in the same direction. In ordinary plowing up and down the hill 

 the small depressions, nearly always found between furrows, and 

 especially the dead furrows, serve as places whore the water col- 

 lects and erosion begins. In contour plowing these ordinary de- 

 pressions are at right angles to the slope and retard rather than 

 encourage erosion. When the reversible plow is used there are no 

 dead furrows except on the crest of ridges where there is but little 

 danger of erosion. 



(5. Contour Seeding. Corn and cotton should be planted on 

 contour lines or nearly so. This reduces the danger of erosion in 

 planter tracks, and the cultivation will be across the slope, which 

 will avoid the formation of small gullies between the rows. For 

 this reason the seeding of oats, wheat and cowpeas should be across 

 the slope, particularly when the drill is used. 



7. Terraces. In those sections where intensive farming is prac- 

 ticed and in fruit districts where the rain falls in heavy showers and 

 the soil does not absorb water readily, terracing is practiced to good 

 advantage (Fig. 17(>). Three types of terraces are in common use 

 the guide row, the level bench and the Mangum. 



(a) The Guide Ron) (Fig. 177) is made by throwing four fur- 

 rows together on contour lines, with an interval of approximately 



Flo. 177. Guide-row terraces. There is no slope from one end of a terrnre to the other, 

 but there is a slight slope from the back of a terrace to the front. (IVarce, R. R.) 



three feet in altitude between the rows. This makes a low Hat ridge, 

 and in order to avoid any waste of land a row of the crop niav be 

 planted on it. This method of terracing is employed on slopes thai 

 do not exceed 1<> per cent, or one foot in ten. and where the soil 

 is open, absorbing the rainfall readily. 



