Soils 



47 



very valuable for cropping purposes, as fertile soil from higher 

 localities has generally been washed down to the low areas for 

 a long time before draining. If the place is swampy, vegeta- 

 tion may have been accumulating and decaying for years, thus 

 forming muck, an extremely valuable soil type for certain 

 crops. There are two methods employed in land drainage, 

 (1) the open-ditch method, and (2) the underdrainage method. 

 Open-ditch drainage. When land is so level that very little 

 grade from the beginning of the ditch to the outlet is possible, 

 open-ditch drainage is employed to lower the water-level. 

 Fig. 19 shows such a 

 ditch on level land 

 in New Jersey. Open 

 ditches are objec- 

 tionable and are not 

 used when under- 

 drainage can be em- 

 ployed. They oc- 

 cupy land that, if 

 underdrained, could 

 be tilled, they inter- 

 fere with the tillage 

 and other cropping 

 operations of the 

 farm, the ditch 

 banks promote the 

 growth of weeds, 

 and the ditches must be cleaned out periodically, which is an 

 expense not necessary with underdrains. However, with all 

 these objections, open ditches are useful and can often be em- 

 ployed profitably where underdrainage is not practicable. Large 

 areas of level muck land can often be effectively drained by 

 means of open ditches that could not possibly be drained by 

 any other method. This is the condition of the land shown 

 in Fig. 19. 



FIG. 19. An open drainage ditch in muck soil 

 in New Jersey. 



