Soils, Fertilizers and Irrigation 153 



Treatment of Alkali. 



/ am advised that in some cases alkali may be drained and that in 

 others it is treated zuith gypsum. 



Gypsum is not a cure for alkali. l)ut simply a means of trans- 

 forming black alkali into white, which is less corrosive and there- 

 fore less destructive to plants, but there may be easily too much 

 white alkali present — so much that the land would be made sterile 

 by it. You cannot remove alkali by flooding unless two conditions 

 can be assured: first, that the water itself is free from alkali before 

 application to the land; second, that you underdrain the land at a 

 depth of from three to four feet with tile, so that the fresh water 

 on the surface can flow through the soil into the drains, carrying 

 away from the land the alkali, which it dissolves in its course. To 

 flood land even with fresh water without making arrangements for 

 carrying off the alkali water below, is to increase the alkali on the 

 surface as the water evaporates, and such treatment does land in- 

 jury rather than benefit. We cannot give you any estimate as to 

 the cost of washing out. It depends altogether upon local condi- 

 tions: whether you use hand work or machinery for the ditching, 

 and what your water will cost. 



Alkali, Gypsum and Shade Trees. 



Kindly advise how to apply gypsum, and hozv much, to heavy, sticky 

 soil, the worst sort of adobe and heavily saturated with alkali. We zvant 

 to plant shade trees. Eucalyptus and peppers succeed fairly well after 

 once started. Gypsum seems to help, but I don't know how much to use. 



The amount of gypsum required to neutralize black alkali de- 

 pends upon how much black alkali there is to be neutralized, and 

 no definite amount, therefore, can be prescribed beforehand as suf- 

 ficient without a determination of the amount of alkali. In some 

 experiments gypsum to the amount of thirty tons to the acre or 

 more has been used just for the purpose of seeing how much the 

 land would take, and a fine growth of grain has been secured after 

 using that much gypsum, but that, of course, would be out of the 

 question because the outlay would be more than the land or the 

 crop would be worth. 



In the planting of trees at some distance apart, the tree can be 

 protected from destruction and enabled to make a stand in the soil 

 by using gypsum on the spot rather than the treatment of the whole 

 surface. In this way five or ten pounds of gypsum could be used 

 by mixing with the soil to fill a good-sized hole. 



Distribution of Alkali. 



I am told by all the ranchers on the east and south sides of the valley 

 that their wells are excellent. But they all say that on the west side they 

 are bringing up alkali. One also said that the zvater level zvas rising 

 throughout all the valley. Is it safe to depend on this in part, or will the 

 alkali spread over all the valley and the foothills? 



