HORTICULTURE 127 



on which to lay the tile. In irrigated lands there are often soft spots 

 which need some special treatment. The best method in such cases 

 is to lay long boards in the trench upon which to lay the tile. If 

 some such precaution is not taken one or more tile may settle or be 

 pressed out of alignment and form a complete obstruction. When 

 laying tile through an orchard with the intention of operating a 

 brush or root cutter, boards with cleats on each side to hold the tile in 

 true alignment are sometimes used. Tiles are not always cut off 

 squarely, and when laid they should be turned until the tops set 

 closely together, leaving the bottoms open for water. The ground 

 should be firm enough to hold a man on a blinded tile, and the tile 

 layer should work from the tile, if need be. Tile should always be 

 carefully covered or blinded, as it is called, as soon as it is laid ; and, 

 for safety, the trench should be back filled enough to prevent the 

 banks from caving in. Sand-trap boxes should always be put in at 

 intervals of 300 to 500 feet, when fine sand or silt troubles occur, 

 and also in orchards. These may be used as inlets for water when 

 flushing tile or boxes. 



After the tiles have been blinded and the trench partly filled 

 by hand, the balance of the filling may be done with horses and 

 plow. Three horses and a long evener are used for the first plowing. 

 This plowing should be from the edges of the trench, after which a 

 team may be used, one horse walking in the trench. It is not neces- 

 sary to fill loosely so that the water may get into the tiles. Tramp- 

 ing and tamping are necessary to prevent surface water from enter- 

 ing and doing much damage. For the same reason, all brush and 

 weeds should be removed, and not used for filling. The plowing 

 should be continued until a heavy black furrow is worked up over the 

 line. 



Subsequent Care Necessary. Attention to drainage should not 

 cease when the system is installed. Upon the subsequent care and 

 treatment of the drains and drained fields will depend the final effi- 

 ciency. One of the greatest sources of trouble, in covered drains es- 

 pecially, has been the damage resulting from surface water running 

 into the trench. In some soils it has been necessary to place boxes 

 or flumes for carrying irrigation water over trench lines to keep the 

 water from finding its way down through the loose soil to the drain 

 with resultant obstructions. These troubles occur in sandy and silt 

 loams but not in clay loams. Tree and brush roots cause much trou- 

 ble by growing into covered drains in search of water, and then 

 developing enough water roots to seriously interfere with the flow 

 of water. To prevent excessive evaporation the proper cultivation of 

 the surface is necessary. Where possible such soils should be culti- 

 vated after each irrigation so as to form a mulch on the surface. 

 Shade crops, such as alfalfa, are also useful in preventing evapora- 

 tion. Cropping and copious irrigation are absolutely necessary for 

 reclaiming alkalied lands after underdrainage is supplied. (F. B. 

 371.) 



Drainage of Humid Soils. All orchard lands should be thor- 

 oughly surface-drained and under-drained. No orchard can endure 



