IN LOAM SOIL 



55 



age by the addition of the pure salts in one part of the 

 experiment and in the other the soil was leached of a por- 

 tion of its alkali sufficient to obtain the required alkali 

 content. The alkali was two-thirds sodium sulphate and 

 one-third magnesium sulphate and in concentrations from 

 10,000 to 50,000 parts per million. The test showed that 

 in a soil containing 25 per cent moisture, rye germinated 

 almost normally with 22,500 parts per million of these 

 salts; barley nearly perfect with 10,000 but less than half 

 normal with 22,500 parts per million in the natural alkali 

 soil; wheat about two-thirds normal with 10,000 parts 

 per million; alfalfa perfect with 10,000 parts per million 

 but producing hardly a sprout in 22,500 parts per million; 

 while turnips and oats produced less than one-half normal 

 germination in soil containing 10,000 parts per million. 

 The time taken for the seeds to germinate was increased 

 in proportion to the salt present even for the lower quan- 

 tities of alkali. 



Table IX summarizes the work of Guthrie and Helms (7) 

 in a rich garden loam soil mixed with nearly an equal 

 quantity of light sand. 



From the figures it is seen that the resistance of seed to 

 alkali during germination is not always the same as the 



