FERTILIZERS IQ 



of fertilizing materials and is always safe to apply 

 liberally. Care should be exercised, however, to 

 have it well worked into the soil or injury to the 

 plants may result. 



Sources of Calcium. — The principal sources of 

 this element as employed for fertilizers are lime- 

 stone, oyster shells, marl, and phosphate rock. 

 Limestone and oyster shells are sometimes ground 

 and applied as a fertilizer, but the usual method is 

 to convert the calcium carbonate of the limestone 

 or shells into calcium oxide or quicklime by burn- 

 ing. In the form of quicklime the calcium is more 

 active in correcting the acidity of soils than in any 

 other form. Lime has both a chemical and a physi- 

 cal effect upon soils. Heavy clay soils are loosened 

 and made tillable by the application of lime, but 

 light soils are rendered more adhesive and retentive 

 of moisture by its addition. The chemical effect of 

 lime upon any soil is to assist in the solution of 

 potash and other plant foods, and prepare them for 

 absorption by the roots. Lime also aids the bac- 

 teria to change the nitrogen in the soil from the 

 nitrite or insoluble form to the nitrate or soluble 

 form. 



Common Salt as a Fertilizer. — Many growers in- 

 sist upon using salt on their celery land, but its 

 value as a fertilizer is doubtful, though it is a fact 

 that celery will assimilate a small amount of salt 

 from the soil, thus gaining a decidedly saline flavor, 

 quite pleasant to the taste. The salt, owing to its 

 chemical composition, has a hygienic influence upon 

 the soil and may assist in the prevention of con- 



