4 



132 Indiana, University Studies 



that this industry has been so highly developed in the latter 

 State and that the cost of the product is kept so low by regulation 

 of freight rates and by convict labor. 



Test for Soil Acidity. Every farmer can easily make his 

 own tests and satisfy himself as to the acidity of his soil without 

 skilled advice. One of the best and easiest methods of testing 

 the acidity of a soil is by what is known as the litmus paper test. 

 The test is made in the following manner: Take a fair average 

 sample of the soil to be tested. To make an average sample 

 take a small portion from several points in the field to be tested, 

 mix carefully and reject one-half the pile, cut thru the middle. 

 Mix the remaining half carefully and reject one-half, repeating 

 the process until only a small portion remains. Moisten the 

 sample with pure water and press together upon a small piece of 

 neutral litmus paper. The presence of acid will cause the litmus 

 paper to turn to a reddish pink color. Allov/ a little time for 

 the action to take place. Be careful not to touch the paper with 

 the fingers after it has been moistened, since perspiration is 

 acid in reaction and will affect the paper. Another method of 

 applying the test is to scrape away a little surface soil and press 

 the paper to the moist earth uncovered. Cover the paper and 

 leave for a few minutes. To obtain good results only the best 

 grade of neutral litmus paper should be used. People are often 

 misled in making this test by the direction to use "blue litmus 

 paper which can be bought at a low price at almost any drug 

 store". In fact, the ordinary blue litmus paper is not sensitive 

 enough to detect a quantity of acid which would entirely prevent 

 the growth of clover. Any druggist can procure the best grade of 

 neutral litmus paper at only a slight additional cost. This small 

 extra cost represents the difference between success and failure 

 in the tests. A good crop of clover which stands well and con- 

 tinues its growth thruout the season is a pretty good indication 

 thatfenough lime is present in the soil for present purposes. 

 But where the clover fails to grow or where it only makes growth 

 for part of the season, limestone can be applied with good re- 

 sults, and in fact its use is imperative for the best results. 



Lime or Crushed Limestone. When a soil is '^sour" the 

 acidity may be corrected by either caustic lime or crushed lime- 

 stone since both react with the acids of the soil to form salts. 

 The reactions are illustrated by the following equations: 



CaO + 2HNO3 = H2O + Ca(N03)2 



