DRAINAGE AND IRRIGATION 27 



a low strip of land upon which the water from the higher 

 ground runs, forming a natural drain for the surface water. 

 Such "draws," as they are called, should be drained. 4. 

 Much of our clay land dries off so slowly, because the water 

 cannot soak down through it quickly, that it should be 

 drained. A tile ditch through a knoll is often beneficial. 

 5. Along hillsides it frequently happens that the water oozes 

 out very much as it does from a spring. A drain put length- 

 wise along the foot of a hill will be very helpful. 6. When 

 such plants as sedges, rushes, and mosses come up naturally 

 on land it needs draining. 7. Land that cracks open badly 

 after drying out needs draining. Such land gets too hard and 

 compact, and the cracking open breaks off the roots of plants 

 growing in it. 



Results of Draining. — The results obtained from drain- 

 ing are many. One of the most important is the greater 

 amount of soil made useful to the plants. When plants grow 

 on wet soils they nearly always have their roots near the sur- 

 face. The plant then draws its food from the surface soil. 

 None of our farm crops will grow with their roots extending into 

 water. When the subsoil is quite wet early in the season, the 

 roots all form in the upper layers of the soil. Later in the 

 season, when the subsoil gets drier, the roots do not follow 

 down after the retreating moisture, but remain near the sur- 

 face. As the plant comes to full growth it draws so heavily 

 upon the soil for moisture that the capillary movement up- 

 ward does not supply enough for the plant's needs, and so the 

 plant suffers. Now, had the land been drained so that the 

 subsoil would have lost its surplus moisture early in the sea- 

 son, the plant roots would have formed lower in the soil and 

 many would have reached down three or four feet or more. 



