374 NATURE AND PROPERTIES OF SOILS 



acid soils, since there is but little active basic material to 

 stimulate the nitrifying" organisms directly or to neutralize 

 the nitrous acid that is formed.^ The addition of lime is the 

 most economical method of supplying this base. This response 

 of the nitrifying bacteria to lime is a matter of great moment 

 to crops that need large amounts of nitrate nitrogen and may 

 account in some cases for the early response of certain crops 

 to liming. The tolerance of some plants to acid soils might be 

 accounted for on the supposition that they need but small 

 amounts of nitrogen or are able to absorb their nitrogen in 

 forms other than the nitrate. 



204. Method and time of applying the lime. — Although 

 lime is lost rapidly from most soils^ appearing in the drain- 

 age water in large amounts, it does not seem to correct to any 

 great extent the acidity of the soil layers through which it is 

 carried.^ Lime applied at the soil surface mil tend to disap- 

 pear, but will have little effect on the soil below. The action 

 of lime seems to be a contact phenomenon and the more thor- 

 oughly it is mixed with the soil, the greater will be the num- 

 ber of active f ocii and the more rapid and effective will be the 

 results of the treatment. 



Lime Is best applied to plowed land and worked into the soil 

 as the seed-bed is prepared. It should be thoroughly mixed 

 with the surface three to five inches of soil. Top dressing of 

 lime is seldom recommended except on permanent meadows 

 and pastures. The time of year at which lime is applied is 

 immaterial, the system of farming, the type of rotation, and 

 such considerations being the deciding factors. The soil 

 should not be too moist when the application is made, as the 



^ 2NH8 + 3O3 = BHISTOa + 2H,0. 

 2HN0a + CaCOa = CaCNO,)^ + H,a -f- C0> 

 CaCNOs)^ + Oa = CaCNO^)^. 

 ''"Wilson, B. D., The Translocation of Calcmm .% a Soil; Cornell Agr« 

 Esfp. Sta,, Memoir 17, 1918. 



Stewart, B., and Wyatt, P. A., Limestone Action on Acid Soils; IH 

 Agr. Exp, Sta., Bnl. 212, 1919. 



