TO STUDY THE NEED OF THE SOIL FOR LIME 67 



examine the paper; if it has turned pink there is acid 

 present in the soil. The amount of acid is roughly indicated 

 by the rapidity of the change and the intensity of the 

 color. 



A thorough examination of the soil requires that samples 

 of both surface and subsoil should be tested at several 

 places in the field. 



(b) Place a small quantity of moist soil in a saucer, 

 add a drop of vinegar or other acid and apply the litmus 

 paper test. Add to the soil in the saucer a spoonful of 

 lime and after adding a little water, mix thoroughly and 

 allow to stand for some time. Again test with the litmus 

 paper and note the result. What has become of the acid? 



Discussion: Acid cannot exist in the presence of lime. 

 The latter is naturally present in some soils but absent 

 in others. The presence of any considerable amount of 

 lime in the soil can be determined in the following manner. 

 Moisten a sample of the soil and mold it into a shallow cup. 

 Pour a few drops of dilute hydrochloric acid * into this cup 

 and, if lime is present, bubbles appear at the surface of 

 the soil. If a large amount of lime is present, foaming 

 will occur. Put a drop of hydrochloric acid on a piece of 

 limestone. 



As in the case of the test for acidity, the test for lime 

 should be applied to the subsoil, since an abundance of 

 lime at a depth of two or three feet may serve a very 



* One part of hydrochloric acid to one part of water. Care must 

 be taken to prevent the strong acid from coming in contact with 

 the skin or the clothing. In case acid gets on the fingers, injury will 

 be prevented if the hand is washed promptly or rubbed with soil. 



