New York Agricultural Experiment Station. 73 



p. 237.) Compared with other mineral constituents lime carbonate 

 is easily soluble in soil water, especially as long as any trace of acid 

 is present. 



On the ordinary farm it is scarcely practicable nor advisable to 

 attempt to go over all the cultivated land with an application of 

 limestone more frequently than once in 4 to 8 years. Besides, an 

 ordinary system of crop rotation lends itself to the practice of liming 

 only about once in 3 to 6 years; unless, of course, the material is 

 applied as a top dressing, which is not so effective as mixing it with 

 the soil. Especially does this apply to alfalfa growing. The problem 

 then is not what is the minimum amount of limestone and maximum 

 fineness for greatest net profit the first year, but rather what quantity 

 and fineness will give the greatest net return over a period of at 

 least three years. If enough of 10-mesh limestone is used to last 

 for that length of time it will, without question, give fully as good 

 results the first year as a somewhat smaller amount of extremely 

 fine material. 



Increased fineness means increased cost and greater waste by 

 leaching. Also limestone ground as fine as dust can hardly be handled 

 in bulk and must be sold in sacks, which adds as much as one dollar 

 per ton to the cost. Ten-mesh limestone, which is about the con- 

 sistency of fine sand, can be readily used in bulk. 



In view of all the above facts, therefore, it seems entirely unneces- 

 sary to urge that limestone be ground any finer than that the entire 

 product pass a 10-mesh sieve and contain all the fine material pro- 

 duced in grinding. 



HINTS ON APPLYING LIMESTONE. 



Quantity to use. — Some idea as to the proper amount of limestone 

 to use can be obtained from a consideration of the amounts that 

 have been used in the experiments previously referred to. Also in 

 some pot-culture studies of this subject at the Pennsylvania station 

 it was found that the most satisfactory results were not obtained 

 until an application was made of at least one ton per acre in excess 

 of the amount needed to neutralize the acidity in the soil. The 

 amount required to neutralize this acidity as determined by the 

 method they used varied from only a few hundred pounds of lime- 

 stone per acre to nearly two tons. 



All things considered, the price of the limestone is one of the main 

 factors determining what is the most profitable amount to use. It 

 is probably not of much practical importance to determine the 

 amount of acid in the soil as an indication of the amount of lime- 

 stone to apply. The important thing to know is whether or not 

 the soil is acid; if it is, limestone should be used liberally. But it is 

 important to note that soils which are just beginning to be acid 

 in the surface seven inches but still have some carbonates in the 



