54 



TOXIC LIMITS OF ALKALI 



'The work of HasclholT (9) on heavy loam and clay 

 soils led him to conclude that because these soils absorb 

 chlorine from the solutions of chlorides and thereby gradu- 

 ally destroy the physical condition of the soil, the injurious 

 influence of chloride solutions on soil productiveness and 

 crop yield takes place gradually. 



Le Clerc and Breazeale (17) found the greater tolerance 

 of wheat seedlings to sodium chloride in clay as compared 





Iflft JM0ifliM BH^M jQSJSM fffi|ffi 



TrrrnTTTTTfT 



Fig. 7. Growth of Wheat with Various Concentrations 

 of Different Salts. 



to sand and solution cultures to be due to the lime which 

 the clay contained. Shutt (25) found that calcium oxide 

 was very effective and calcium carbonate less so in correct- 

 ing the toxicity of soil containing 50,000 parts per million 

 of magnesium sulphate. Even when calcium oxide was 

 used, germination was still retarded but a larger percent- 

 age of the plants grew and the growth was more healthy. 

 This antagonistic action of calcium and other salts will 

 be taken up in greater detail in Chapter VIII. 



In the work done on the germination and growth of 

 plants in Wyoming by Buffum (2), alkali soils were leached 

 of their alkali and then made up to the required percent- 



