252 



SOIL ACIDITY AND LIMING 



again with blue litmus paper. Into the other tumbler pour the teaspoonful 

 of the fine material, stir for a few seconds, and test with blue litmus paper. 

 Esqplain results. 



B, Repeat the test but use pure gypsum (calcium sulfate) instead of the 

 finely pulverized lunestone. 



Laboratory Exercises. — Material Needed.-^^everal small strips each of 

 blue and red litmus paper; 8 tumblers; about a cupful each of 3 soils to test 

 for acidity; a half cupful each of a conunon salt solution, soapy water, vinegar 

 solution sweetened with sugar, and sour nulk or whey; four or five saucers; 

 a piece of window glass; a smaU amount of pure gypsiun (calcium sulfate); 

 4-quart samples of agricultural limes; a bottle of muriatic acid; and a quart 

 of coal ashes. 



To Determine the Reaction of Dijfferent Solutions by the Use of Litmus 

 Paper. — Procedure. — A, Dip a small piece of blue Htmus paper into an acid 

 solution provided. What happened? Try a piece of red htmus paper. Any 

 reaction? Acid tm:ns blue htmus paper red. 



B. Dip a piece of blue htmus paper into an alkaline solution. Any reac- 

 tion? Test with a piece of red htmus paper. What change takes place? 



An alkahne solution turns red litmus paper blue. An alkaline solution 

 has an opposite reaction to that of an acid solution. 

 C Test pure water with blue and red Htmus paper. 

 Water is a neutral material, neither acid nor alkaline. 

 D. By the use of blue and red Htmus paper determine the reaction of the 

 following solutions: 



A common salt solution; soapy water; vinegar solution sweetened with 

 sugar; and sour milk or whey. 

 Question. — ^What is Htmus? 



To Test for Soil Acidity by the Use of Blue Litmus Paper — Procedure. — 

 A. Place about 3 tablespoomuls of soil in a clean saucer and moisten to a thick 

 mud with clean, soft water, previously boiled. With a clean stick separate 

 the mud into two portions and lay on one portion a piece of blue Htmus paper. 

 Press the other portion of wet soil firmly down on the paper; leave for about 

 3 to 5 minutes, then carefuhy remove the upper portion of the soil and examine 

 the paper. Note results, and interpret. 



B. Test another soil, but this time place the piece of blue Htmus paper 

 between the two halves of a mud ball. 



C. Test a third soil. This time lay Htmus paper on a piece of window 

 glass, and cover with one-half of a mud baU. 



To Show that Lime Will Correct Soil Acidity. — Procedure. — ^A." Place 

 about three tablespoonfuls of acid soil in a clean saucer and thoroughly mix 

 with it about a quarter of a teaspoonful, or less, of air-slaked lime. Moisten 

 the mixture and test with blue Htmus paper as before. (Select either one of 

 the three methods.) 



B. Repeat and use pure gjrpsum (calcium suKate) instead. 



Question. — What effect did the lime have on the acid soil? 



To Study Different Forms of Agricttltural Lime, — Procedure. — ^Examine 

 carefully the samples of different agricultural limes provided and record facts 

 and observations in tabular form as follows: 



Common 

 name 



Carbonate, 

 hydrate or 

 quick lime 



AppKcation 

 per acre 



Cost 

 per ton 



Characteristics : color, 



fineness, moisture 



content, carbonate 



content 



