1906.] LIMING SOILS AND PLANTS. "J"] 



rock and the agricultural conditions were miserable in an ex- 

 treme degree until the construction of a railroad rendered it 

 possible to introduce lime at a reasonable cost. 



Several of these European writers referred to the soils as 

 positively acid. 



In view of the knowledge of these conditions in other 

 countries it seemed probable that the difficulty in Rhode Island 

 was due either to soil acidity and a lack of sufficient carbonate 

 of lime in the soil, or to the absence of the organisms which 

 are capable of changing the ammonia intO' nitric acid. 



The first step actually taken was to test the soil for acidity 

 or a lack of carbonate of lime, by means of several different 

 chemical methods. Of these the blue litmus paper test was 

 found to be the most trustworthy of the simple tests. 



HOW TO MAKE THE TEST WITH BLUE LITMUS PAPER FOR AS- 

 CERTAINING THE NEED OF LIME IN SOILS. 



Concerning the test, the best plan for farmers to pursue 

 is to have the soil tested if possible by the Experiment Station 

 Chemist, for familiarity with the method enables one to ar- 

 rive at a more correct judgment concerning the probable lime 

 requirement. Still other and more elaborate tests can also be 

 made in the laboratory. 



In making the blue litmus paper tests the soil is first mois- 

 tened until it is of about the consistency of a thick porridge. 

 It is then parted, a strip of blue litmus paper (two inches long 

 by half an inch wide) inserted and the soil pressed around it. 

 After an hour or two the paper can be removed and rinsed by 

 dipping in water a little less deeply than it was inserted in the 

 soil. The end introduced into the soil should not be touched 

 with the fingers. If this latter precaution is taken and it is 

 found upon removal that the paper has entirely lost its blue 

 tint and an intense pinkish red or brick red color has taken its 

 place, it is probable that the soil needs liming. 



FURTHER EXPERIMENTS WITH THE KINGSTON SOIL. 



The soil where the sulphate of ammonia proved injurious 

 turned a blue litmus paper rapidly red. It was tested to as- 

 certain if proto-sulphate of iron, an occasional toxic constitu- 



