658 SOILS: PBOPEBTIJSS AND MANAGEMENT 



drop and be well protected by wing walls. Lines of 

 drains should be connected in systems for this purpose. 

 Unless the drain has a high grade the outlet should not be 

 covered by water. The end of the tile should be pro- 

 tected by a gate or a series of rods to prevent the entrance 

 of small animals. 



560. Muck and peat soil. — Muck and peat soil should 

 usually be drained by open ditches at first. After learn- 

 ing the nature of the material and the structure of the 

 subformation, it may be found permissible to install tile 

 in the smaller ditches. When the organic material is 

 more than four feet deep, so that tile could not be laid 

 on a hard bottom, much risk is involved in its use due 

 to the excessive shrinkage of such soil when the surplus 

 water is removed and when even moderate drying occurs. 

 If the area is fed by springs so that the water level will 

 be kept permanently at the base of the tile, the shrinkage 

 will be very small and the tile may usually be laid with 

 safety, especially if placed on boards to aid in keeping 

 the alignment. In so-called dry peat, where the subsoil 

 may dry out seriously in summer, the use of tile is inad- 

 visable. In muck soil, which has a finer texture resulting 

 from a more advanced stage of decay, tile drains may be 

 used with greater safety. _ , 



The distance between drains in muck should be from 

 one hundred to five hundred feet, depending much on 

 the nature of the subsoil. Since the surface is likely to 

 be relatively flat, nothing smaller than four- or five-inch 

 tile should be employed and the joints should be carefully 

 protected as described above. 



Since the capillary power of muck soil is low, the water 

 table should not be lowered more than from two to three 

 feet, depending on the quality of the soil. While the 



