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Report on Inspection Work of the 



AMOUNT AND COST OF PLANT-FOOD IN CALCIUM (LIME) COMPOUNDS. 



Calcium or lime compounds are being used in increasing amounts 

 by farmers for application to soils. The forms in use are ground 

 limestone (impure calcium carbonate), slaked or hydrated lime 

 (calcium hydroxide), usually mixed with more or less carbonate, and 

 quicklime, or burned lime (calcium oxide). These forms all vary 

 much in the amount of calcium they contain. Nearly all samples 

 contain magnesium compounds, varying in amount from 1 or 2 per ct. 

 to nearly 40. Magnesium carbonate, hydroxide and oxide are useful 

 in neutralizing acids in soils, their neutralizing power being greater, 

 pound for pound, than the corresponding calcium compounds. In 

 the table below, we give the percentages of calcium (Ca) to include 

 magnesium (Mg) (the magnesium being previously calculated to an 

 equivalent of calcium). 



Table XVI. — Amount and Cost of Calcium in Lime Compounds. 



In the samples examined by us the average cost of calcium is great- 

 est in the form of carbonate, and least in that of quicklime, while in 

 the form of slaked lime the cost is intermediate. Even the minimum 

 prices found above are high in comparison with the prices at which 

 these materials can be purchased. Ground limestone containing 

 nearly 40 per ct. of calcium and magnesium can be obtained by many 

 farmers in this State at a cost of $2.50 per ton, in which case the 

 cost of one pound of calcium is about 0.3 cent. Quicklime can be 



