8 MASS. EXPERIMENT STATION BULLETIN 444 



Pot Tests 



During the period from 1928 to 1932 studies of the effect of various treatments 

 of the soils from these plots were made by means of pot tests. 



The pots used were in part Wagner pots holding 17 kilos of soil and in part 

 earthern jars holding 12 kilos of soil. All tests were made in replication of five 

 jars with the same treatment; a total of usually 120 pots was used each year. 

 Soil was brought from certain plots and weighed, sometimes for each pot and 

 sometimes enough for a five pot lot. One lot of five did not receive any treat- 

 ment and other lots of five were variously treated as shown in the tables. 



Seedling peach trees were used as indicators. Sometimes they were self-pol- 

 linated Belle of Georgia seedlings and sometimes a miscellaneous lot of seedlings. 

 They were started in flats filled with sand or sawdust. When the plants were 

 4-8 inches tall they were carefully graded as to size and origin and set, one plant 

 in each pot, in late May or early June. They were watered carefully through a 

 tube reaching to the bottom of the pot and the soil was not allowed to become 

 excessively wet or dry. Care was necessary because the pots had no drainage. 

 The pots were placed on cars holding 20 pots each, on tracks so that they could 

 be rolled into a glass house when rain threatened and outside in clear weather. 



The little trees were allowed to grow until leaf fall when they were removed 

 from the pots, together with as many as possible of the roots, placed in a dry 

 place to become thoroughly air dry, and then weighed. 



Table 6.— Pot Cultures, 1928 



Table 7. — Pot Cultures, 1929. 



* Five pots received each treatment, 

 meaning: 

 No treatment 

 N Nitrate of soda 

 P Precipitated bone 

 K Potassium chloride 



The letters and figures in this column have the following 



L Magnesium limestone 



Ca Calcium carbonate 



The figures indicate grams per 17 kilos of soil. 



