WATER SOILS. 831 



54 per cent, or twice as much. The highest [)ercentage of inagnesiuia sulpliate in 

 the \vater-sohil)le is 24 ]>er cent, found in the first 2 in. of soil, while the average for 

 the 2 sainjiles of alkali is 2S per cent. The decrease of the calcium sulphate from 

 theauiount present in the water-soluble to that i)resent in the alkali, is more marked 

 than the increase in the sodium sul})hate in the alkali given a])ove. The miuitnum 

 of the calciuui salt found in tlie water-soluble is 84 jier cent, the maxiiuum 67 per 

 cent, while the amounts in these alkalis are 7.5 and 3.8 per cent, respectively. . . . 



"The water-soluble in the soil is not identical with ground water solutions, j)roba- 

 bly due to reactions dependent upon the relative masses, which react upon each 

 other within the soil and during the extraction. The reactions near the surface of 

 the soil are quite different from those more remote. This is indicated by the solu- 

 tions yielded by samples taken to depths of 2 and 4 in." 



The efflorescent alkalis are quite different from the residues left by evaporating 

 bodies of water; such residues seem to l)e intermediate between those oljtained by 

 evaporating ground waters to dryness and the salt brought to the surface by capil- 

 larity and separated as efflorescences on the ground." 



Other conclusions from the studies reported are as follows: 



"The readiness with which the chemical reactions take place and their character, 

 as indicated by the salts present in the ground waters, probal^ly have a direct and 

 important bearing upon the fertility of the soil. The loessial soils of the plains agree 

 with the ordinary i>rairie soils in the chemical composition of their mass and in the 

 general results of the agricultural analysis, but not in the mechanical analysis. 



"The analyses of the whole soil mass and of the different i)ortions of the fine earth 

 suggest important differences between the unchanged rock imrticles in the soil and 

 the finer jiortions which have suffered change or are the products of alteration. 



"The aggregate amount of soluble salts per acre whose movement is effected by the 

 water falling on or supplied to the surface, or by its evaporation from the surface, is 

 large; we make it 9 tons in one instance. The application of water, irrigation, may 

 carry the soluble salts so deep into the soil that a long time may be reouired for them 

 to come near to the surface again. 



"There is in the samples of soil examined Ijoth free ammonia and ammoniacal 

 salts, which we interpret as indicating unfavoi'able biological conditions, which view 

 is materially strengthened ])y the nitrates in the ground waters. 



"There is a significant gain in the total soil nitrogen during the time of the experi- 

 ment which may have been favored by, but was not dei)endent upon, the applica- 

 tion of manure. 



"The nitrates in the first 2 in. of this soil are from 9 times to 200 times as great as 

 in the second 2 in., corroborative of the suggested reduction in certain zones of the soil. 



"Air-dried soil samples can be kept for a year or more with ordinary precautions 

 without material change in their nitrogen content. 



"The humus in this soil is nearly as abundant as in average Eastern soils, and we 

 were unal)le to find anything about it markedly different from ordinary hunms. It 

 is unlike the humus of arid soils in that it is not so rich in nitrogen as they have been 

 found to be. 



"The solutions of the humus carried relatively very large amounts of silicic acid, 

 phosphoric acid, potash, and lime. The precipitated humus did not carry much lime. 



"The effect of the cultivation, manuring, etc., for three seasons, may be sununed 

 up ]jy stating that the store of plant food in the surface soil, taken to a depth of 10 

 in., was actually increased. This, however, was the lesser part of the improvement, 

 the greater part lay in the betterment of the general conditions, whose best features 

 can not be shown by (;hemical analysis or expressed in any fornuila." 



Soil survey around Imperial, Cal., T. II. Me.vns and J. G. IIoi,mi:s {U. S. 

 Dept. Ayr., Bureau fi/'>SW'fe Circ. 9, pp. ,iO, jhjs. 2). — This is an account of an examina- 



25832— No. 9—02 3 



