H. B. Hutchinson and K. MacLennan 



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(i.e. soluble in ammoniuiu chloride solution) tends to react as an alkali, 

 and the "loss on ignition" portion acts as an acid component there 

 should obtain a definite ratio between these two for the production of 

 a neutral soil reaction. According to Weibull, it ma}^ be stated that 

 (I) ordinary soils with 3-6 % "loss on ignition" and less than 0-.30 % 

 soluble lime are acid in character and possess low nitrifying power ; 

 soils poor in lime and with a more neutral reaction have a lower "loss 

 on ignition" content. 



Soils with traces or more than traces of calcium carbonate, or 

 soils without carbonate but with more than 0-2.'j % available lime, 

 are, as a rule, alkaline and possess a marked nitrifying power; as 

 exceptions are soils with high humus content. If the ratio lime: "loss 

 on ignition" fell below 1 : 20 the soils examined were acid in character; 

 if above 1 : 20 the reaction was alkaline. Meyer examined a number 

 of soils in this respect and found good agreement on the whole between 

 the lime content : loss on ignition ratio and the reaction of the soil. 



Table III. Relation between the Lime Requirements of some Danish 

 Soils and the percentage of Lime soluble in Ammonium Chloride 

 Solution {Chrislensen and Larsen). 



His analytical data are, however, difficult of interpretation — one soil 

 possessing 0-372 % soluble Ume (CaO), 0-126 % COg (= 0-286 % CaCOg), 

 an acidity of 0-054 % (expressed as COo) and an acid reaction, but did 

 not respond in pot culture to an application of calcium carbonate. Of 

 the six soils with which Meyer worked three possessed a hme content 

 above the normal (0-25 %), five are stated to be acid in character, but 

 only one was found to respond to carbonate applications. Briefly, the 

 analytical data failed to throw any light on the need of lime. In con- 

 nection with an extensive scheme of liming experiments initiated by the 



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