Indiana Soils Containing an Excess of Soluble 



Salts. 



S. D. Conner 



The usual procedure when making a la})oratory examination of an In- 

 diana soil is to test for a probable deficiency of lime, organic matter or plant 

 food elements. There are, however, some soils from the humid section that 

 have too much rather than too little plant food and soluble salts. The bulk 

 of such soils are peat, muck or black sand soils that were formed in poorly 

 drained sections. The only clay or loam soils in humid regions which have 

 excess soluble salts are very local in area and are formed by artificial rather 

 than natural causes. 



The black soils high in soluble salts are of two general types. One type 

 contains relatively small amounts of soluble salts of a highly toxic nature. 

 An example of this type is the acid black sand of the Wanatah experiment 

 field where the soluble matter is largely aluminum nitrate, a salt very toxic 

 to the roots of agricultural crops. Results of experiments on this soil are 

 published in Bulletin 170, Purdue Agricultural Experiment Station. 



Another type of the black soils under discussion contains relatively 

 small amounts of toxic salts but very high concentration of salts of low tox- 

 icity. One such soil was sent to the Experiment Station laboratory from 

 Starke County. The samples were taken from an onion field on muck soil 

 in September, 1913. Where the onions were dying the soil contained .44% 

 nitrates and 1.2% soluble salts. Where the onions were doing well the soil 

 contained .10% nitrates and only .45% soluble salts. Another case where 

 soluble salts seemed to be the cause of injury to onions was reported from 

 muck soil in Noble County in July, 1916. Samples taken from the part 

 of the field where the onions were dying contained .50% nitrates and 1.12% 

 soluble salts, while the soil from the part of the field where the onions were 

 still good contained .17% nitrates and .57% soluble salts. 



Quite a number of cases have been reported where both onions and corn 

 on muck soil seemed to be failing or were entirely destroyed because of a 

 high concentration of sqluble salts. Analysis of water extracts of such soils 

 show that the soluble salt is composed largely of calcium and nitric acid. 

 The occurrence of this salt in such soil is not hard to explain as the soils 

 contain large amount of nitrogenous organic matter and calcium. During 

 the warm weather of summer nitrification is very active and calcium nitrate 

 is formed in great quantities. As the soil moisture evaporates this salt 

 together with any other soluble matter is carried to the surface and deposited 

 in such quantities that the salts act in the same manner as the alkali salts in 

 Western soils. Calcium nitrate is an excellent fertilizer for thin lands but 



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