Fertilizers 19 



as 8 to 12 tons to an acre. Many farm crops are bene- 

 fited by an application of ground limestone, even when 

 the soil does not show acidity. Plants of the legume 

 family are especially benefited by such an applica^ 

 tion. Celery, lettuce, cabbage, citrous fruits, hay and 

 forage crops, generally prefer a large supply of lime in 

 the soil. Watermelons, on the other hand, do well on an 

 acid soil. 



It is best to apply ground limestone to the soil a con- 

 siderable time before the crop is to be planted. The 

 application should be made before plowing, as this will 

 give an opportunity to incorporate the material more 

 evenly with the soil, and will give the beneficial soil or- 

 ganisms an opportunity to increase to large numbers. 



If it has not been possible to apply ground limestone 

 before the soil is broken up, it may be applied before 

 planting time. It is advisable, however, to apply it a 

 considerable time before one wishes to use fertilizer, 

 since the acid phosphate of the fertilizer on coming in 

 contact with the ground limestone is likely to be reverted 

 more quickly than desirable. 



Formerly it was considered necessary to have the lime- 

 stone ground into a very fine powder ; later experimenta- 

 tion has shown that a rather more coarsely ground lime- 

 stone is quite as beneficial and more lasting. Hopkins, 

 of the Illinois Experiment Station, considers that the 

 limestone is ground fine enough if it can pass through a 

 sieve with 10 meshes to the inch. Since there are in- 

 cluded in this material all the finer particles that are pro- 

 duced in grinding, a sufficient amount of lime will be 

 available at once for the needs of the plants. 



