96 Effective Farming 



of ground limestone, fifty-six pounds of quick-lime, and seventy- 

 four pounds of hydrated lime have the same value. 



When choosing lime for use on soil, the farmer must keep in 

 mind the fact that caustic lime burns out the soil humus. To 

 keep up the supply of humus in soil is one of the most impor- 

 tant factors in maintaining soil fertility and, except in the case 

 of muck or peat soils, farmers cannot often afford to lose this 

 valuable product. The results of long-continued field tests 

 at several experiment stations show that ground limestone 

 gives the best results. At the Pennsylvania Station, when 

 caustic lime was used, less yields were secured and larger quan- 

 tities of organic matter were destroyed than when ground 

 limestone was used. And a very significant fact about the 

 results at this station is that for every ton of caustic lime ap- 

 plied to the soil, the equivalent of four and one-half tons of farm 

 manure was destroyed. The nitrogen in the manure would 

 cost about $7.00 if purchased in commercial fertilizer. It 

 should be stated in this connection that authorities do not 

 agree about the relative values of these two kinds of lime. 

 Some advocate the use of caustic lime, stating that it is quicker- 

 acting, which is the case, and, further, since about half the 

 quantity is required, the saving in freight rates of such a bulky 

 product is a factor to be considered. It must be remembered, 

 however, that about $7.00 of nitrogen is destroyed for each ton of 

 caustic lime used and that this money will pay many freight bills. 



Whether to use hydrated lime or some other form will de- 

 pend largely on the price of the product and the amount of 

 money that can be saved in freight charges. Less hydrated 

 lime is used for soil improvement than the other forms. 



45. Quantity of lime to apply. The usual first applica- 

 tion of ground limestone is four tons an acre followed by two 

 tons every four years. In very sour soils these amounts may 

 well be increased. There is no danger of applying too large a 

 quantity. Caustic lime is usually applied at the rate of 1000 

 pounds to the acre and hydrated at the rate of 1500 pounds. 



