138 FARM DEVELOPMENT 



have an excess of soluble alkaline compounds. Flood- 

 ing the land, and then drawing off the water after it 

 has dissolved a quantity of alkali, is a plan 

 which has been suggested for heavy, flat lands, but it 

 is not practicable in most cases. Dressing heavily with 

 rotted barn manure has a temporary, beneficial effect, 

 as has also sometimes burning a thick layer of straw 

 upon the soil and thus charring the surface. 



Irrigating the alkaline soil with a surplus of water 

 which is carried off by means of underground drains, is 

 an expensive method of leaching out the excess of salts, 

 which is successfully used in some districts where irriga- 

 tion is practiced. Irrigation may, in many cases, in- 

 crease the injurious effects of alkali by supplying to the 

 soil large amounts of water which sink down to only a 

 short depth and are returned to the surface by capillary 

 action. Upon evaporation, this water deposits, or leaves, 

 at the surface of the soil, soluble salts which it absorbed 

 from the subsoil. The water in passing down through 

 the soil goes so rapidly that it does not again dissolve 

 all these soluble salts, and thus they gradually accumu- 

 late in the furrow-slice, and the roots of the plant are 

 obliged to feed in a soil too strongly impregnated with 

 the substances which, in smaller quantities, would allow 

 them to thrive and grow. Seepage waters coming 

 through pervious layers of earth, from higher areas, and 

 moistening hillsides or lower areas, often, upon evaporat- 

 ing, leave alkaline deposits resulting in " alkali spots." 

 Under-drains and open ditches, to divert the seepage 

 water, are sometimes effective in preventing the ac- 

 cumulation of alkali on the surface or in remedying 

 alkalinity. 



Terracing hillsides is sometimes done in fields of con- 

 siderable size. In gardens it is frequently resorted to, 

 that cultivation may be made easier, to prevent the soils 

 being furrowed out so badly by the waters washing down 



