84 SOILS AND FERTILIZERS 



Some shrubs, as grease wood, and weeds, as Russian 

 thistle, take from the soil large amounts of alkaline 

 matter, and it is sometimes advisable to remove a 

 number of such crops so as to reduce the alkali. A 

 slightly beneficial effect is sometimes noticed on small 

 < alkali ' spots where straw is burned and the ashes are 

 used, forming potassium silicate. As a rule ashes are 

 more injurious than beneficial, on an 'alkali' soil. 

 Irrigation and thorough drainage, if continued long 

 enough, will effect a permanent cure. Irrigation 

 without drainage may cause a more alkaline condition 

 by bringing to the surface subsoil alkali. The waters 

 from some streams and weils are unsuited for irriga- 

 tion on account of containing too much alkaline mat- 

 ter. Mildly alkaline soils will usually repay in crop 

 production all the labor which is expended in making 

 them productive, and when brought under cultivation 

 are frequently very fertile soils. A small amount of 

 alkaline compounds in a soil is beneficial ; in fact, 

 many soils would be more productive if they contained 

 more alkaline matter. 



99. Improving Small Tracts of < Alkali' Land. 

 When the places are located so that they can be under- 

 drained at comparatively little expense, this should be 

 done, as it will prove the best and most permanent 

 way of removing the alkali. Good surface drainage 

 should also be provided. Quite frequently a quarter 

 or more of the total alkali in the soil will, in a dry 

 time, be found near and on the surface. In such cases, 

 and if the spots are small, a large amount of alkali 

 can be removed by scraping the surface and then cart- 



