38 THE SOIL OF THE FARM. 



aside into ditches or aqueducts, tlirongh wliicli it is con- 

 ducted to the fields, where it is divided into smaller rills, 

 and finally spread over the surface, sinking into and 

 through the soil. When it is desirable to bring more 

 water upon meadows than is required for saturating the 

 ground, and its escape to fields below is to be avoided, 

 other ditches should be made at intervals upon the slope, 

 to arrest and carry aAvay the surface water. 



Ridge-and-Furrow or Bed-Work System. — Where the 

 land is nearly level throughout its surface, it is laid out in 

 a series of ridges. Along the top of these the irrigating 

 channels are led, from which the water flows over either 

 side, being taken up by the furrows, which occupy the 

 hollows between the ridges. Erom the main conductor, 

 and at right angles to it, the various feeders are taken off. 

 These consist of smaller trenches four or five inches in 

 depth, made widest, say twelve or sixteen inches where 

 they issue from the main conductor, and gradually lessen- 

 ing as they recede from it. They may be formed at dis- 

 tances of ten yards or less; being made nearer on stiff soils, 

 and further apart where the soil is loose and porous. They 

 occupy the ridge lines of the lands in which the field is 

 laid, and the furrows in the hollows between these lands 

 communicate with a main surface drain, at the lower 

 part of the meadow. The drain conveys the water back 

 to the river from which it was taken ; or becomes in its 

 turn the main conductor to another meadow on a lower 

 level ; and in this way several meadows may be irrigated 

 by means of the same water. This is known as the Bed- 

 Work or Ridge-and-Furrow system. It is only suitable 

 to grass lands, and to land which has nearly a level 

 surface. 



The Tatch-Work System. — On a sloping surface a dif- 

 ferent plan must be adoj^ted for the conveyance and dis- 



