654 



STATE BOARD OF AGRICULTURE. 



The growing plants reduced the salt content of the soil solution in 

 medium sand from 300 to 125 parts per million and in the sand}^ loam 

 from 550 to 50 parts per million. 



These results indicate that the soluble salt content of the soil may 

 be greatly reduced under very intensive cropping. 



In order to obtain additional information on this question larger con- 

 tainers were employed. Barley and corn were grown in pots containing 

 three kilograms of soil, the concentration of the soil solution being 

 determined at different stages of their growth. The results derived from 

 this series are set forth in table 20. 



TABLE 20. — EFFECT OF PLANT GROWTH ON THE SOLUBLE SALT CONTENT OF SOILS. 



These data show that in six weeks barley reduced the soluble salt 

 content of medium sand from 300 parts per million to 75 parts and of 

 sandy loam from 750 parts per million to 250 parts. These are very 

 substantial decreases. 



After nine weeks the concentration of the soil solution was equally 

 low and after twelve weeks all soluble materials as lueasiired by the 

 freezing point method had been removed from the sand and that in the 

 sandy loam was reduced to 100 parts per million. The results with 

 corn agree perfectly with those obtained with barley. 



Another series was run in containers holding approximately 8 kilo- 

 grams of soil. In order to overcome the effect of salt movement and 

 other factors which tend to an uneven distribution of soluble material 

 in soils, sufficient water was added to make a thick cream and the soil 

 stirred thoroughly. Samples were then withdrawn by means of a spoon. 

 The data obtained are presented in table 21. 



