QUESTIONS 253 



Test the different materials for carbonates by placing about a quarter 

 of a teaspoonful in a tumbler and pouring on a few drops of diute mraatic acid. 



Questions, — (a) What kind of gas is given off when a carbonate is treated 

 with acid? 



(b) What becomes of much of this gas after it escapes into the air? 



(c) What is a carbonate? 



(d) Name three carbonates. 



(e) What kinds of carbonates are present in pure limestone, wood ashes, 

 and air-slaked lime? 



(/) Would you use coal ashes as a neutralizer for acid soils? As a fertilizer? 



Home Experiments or Projects. — Object. — ^To demonstrate the profitable 

 use of agricultural lime on acid soil for alfalfa, clover, lespedeza or peas. 



Procedure. — Select an acre or half an acre of well-drained acid soil. Divide 

 into two portions. Thoroughly lime one plot and leave the other plot unlimed. 

 Sow alfa&a, peas, lespedeza or common medium red clover. Inoculate both 

 plots. Determine to what extent the use of lime increased the value of the 

 land as an income producer. (Consider the crop grown.) Determine net 

 profits in the use of lime (Fig. 149). 



To Demonstrate the Need of Both Lime and Phosphate on a Long- 

 cropped Acid Soil. — Procedure. — Select an area of acid sod, divide into two 

 strips, and lime, as described m above project. After the lime is thoroughly 

 mixed into the soil by disking, apply acid phosphate on one-half of each 

 strip at the rate of 300 pounds per acre. "Drag" the fertilizer into the soil. 

 Plant com the first year, grain the second, and clover the third. Apply 200 

 pounds of acid phosphate for grain the second year. Apply the fertilizer to 

 the same end receiving the phosphate for com. Do not fail to inoculate the 

 whole area for the clover. 



Determine the net profits from liming and the use of lime and phosphate 

 for the 3-year period. 



Field Studies. — 1. Collect sample of soils from a few fields showing indi- 

 cations of acidity and test for acidity either in the field or laboratory. 



2. Collect samples of soil from areas growing good clover or alfalfa and 

 from areas where the clover or aKalfa failed or is growing poorly. Test the 

 soils for acidity. 



QUESTIONS 



1. What is the meaning of soil acidity? 



2. Why is soil acidity harmful? How can this condition be corrected? 



3. What is meant by liming? Agricultural lime? 



4. Discuss the beneficial effects of liming. 



5. Under what conditions does green manuring give best results? 



6. What crops in particular give most direct profits from liming? Name 



other crops benefited directly by liming. 



7. Name several crops especially adapted to "acid agriculture." 



8. Besides clover, a farmer grows com, wheat, oats and timothy in a five-year 



rotation on acid soil. If he were to lime his land could he expect profit- 

 able returns from the other crops as well as from the clover? (Table, 

 page 231.) 



9. How may acid soils be determined? 



10. Describe the blue litmus paper test for acidity. 



11. How may certain weeds indicate acidity? 



12. What relation is there between soil acidity and low wet lands? Discuss 



this point. 



13. How do soils become acid? 



14. How extensive are acid soHs? 



15. Can soil acidity be reduced through leaching? Explaia. 



