EXPERIMENT STATION BULLETINS. 



651 



The above results show tliat the soluble salt content of different muck 

 soils is (luite variable, especialh^ in the npper layers and becomes quite 

 high in some, several days after a rain. When it is considered that these 

 determinations were made with saturated soils the conclusion that the 

 concentration at medium or low water contents may become quite great 

 and thereby injure plants, seems tenable. 



Another interesting soil condition was found. Mr. Severance of Lan- 

 sing reported that his tomato plants were developing very slowly regard- 

 less of the fact that they were properly watered and otherwise treated 

 normally. The soil had been used for greenhouse purposes for eight 

 years. A flat of plants was brought to our laboratory, an examination 

 revealed that they were not diseased but showed characteristic develop- 

 ment of plants grown in solutions of high osmotic pressure. The soil was 

 sampled and the soluble salt content determined as usual. It was found 

 to have a freezing point lowering of 0.115° which of course is several 

 times greater than normal soils. He was advised to leach the soil by 

 means of the garden hose. Later reports were to the effect that the 

 plants grew in the flats that were so treated and developed at a more 

 rapid rate than those that were watered as usual. We obtained a quan- 

 tity of the soil and reduced the salt content of one portion by percolating 

 distilled water through it. It was interesting to find that one inch 

 of water removed much of the soluble salts from this soil. 



TABLE 17.— REMOVAL OF SOLUBLE SALTS FROM GREENHOUSE SOIL. 



In making the extractions a two-inch layer of soil was placed in a 

 tube 4 inches in diameter, brought to the saturation point and the above 

 amounts of water passed through it. A nitrate determination of the soil 

 revealed that it contained 2898.5 parts per million, or much of the 

 total soluble salts was made up of nitrates. 



Flats were then filled with the leached and unwashed soil, respectively, 

 and tomato, lettuce and radish seed were sown. The germination of the 

 seed in the former case was 75 per cent less than in the latter and at the 

 end of 14 days the average heights of the plants were as given in table 18. 



