6 The Bulletin 



is replaced, first, by double log houses, then by frame, and, farther on, 

 by brick buildings, with other unmistakable evidences of prosperity. 

 Thus this is seen in passing from the mountainous regions of Kentucky 

 into the blue-gi*ass country, which is throughout underlaid Avith calca- 

 reous formations. Thus, likewise, in crossing the strike of the calcareous 

 formations of Alabama, Mississippi, and Louisiana, or other regions 

 where the underlying formations of calcium have contributed to the 

 formation of the soils, as compared with the adjacent districts where 

 this is not the case. This and other illustrations give rise to the proverb 

 that a "Lime country is a rich country." 



EFFECT OF CALCIUM CAKBOATE ON THE ACID PHOSPHATE OF THE 

 SOIL IX THE PKESENCE OF IRO> AND ALIMIMTI OXIDES 



We will now discuss the effect of lime in the soil on the availability 

 of soluble phosphoric acid, especially where the soil is heavily charged 

 with the oxides of iron and aluminum. Practically all of the soils of 

 North Carolina, and especially those of the Piedmont and mountain 

 sections, are derived from rocks carrying very large amounts of iron 

 and almiiinum. Leading constituents of clayey soils everywhere are sili- 

 cates and hydrated oxides of aluminum, and the red and yellow colors 

 in all soils and subsoils are due, generally, to the presence of iron oxides. 

 All of our piedmont soils are heavily charged with iron and aluminum 

 compounds, and our coastal plains soils are also well supplied with these 

 chemical bodies. The direct effect, therefore, of these oxides on the solu- 

 ble phosphoric acid of the soil is well worth our careful consideration. 



In E. S. R.,* Vol. 28, Xo. 3, we find a report of pot experiments 

 with wheat which show that the addition of lime increased the avail- 

 ability of phosphoric acid in such relatively insoluble phosphates as 

 wavellite, an aluminum phosphate, and vivianite, an iron phosphate. 



Mr. James E. Llalligali of the Louisiana Experiment Station, in his 

 work on "Soil Fertility and Fertilizers," states, page 237 : "Most soils 

 contain iron and aluminum which are united with more or less phos- 

 phoric acid. These phosphates are very SLIGHTLY soluble in soil 

 solutions, and the addition of LIME LIBERATES SOME OF THE 

 PHOSPHORIC ACID by combining with part of the iron and alu- 

 minum phosphates." 



In Bulletin N^o. 46 of the Rhode Island Experinn'ut Station, Dr. 

 Wheeler says, in his discussion of the chemical action of lime on soils, 

 "If lime is present in a soil to which ordinary commercial fertilizer, 

 dissolved bono black, dissolved bone, phosphoric asid or double super- 

 phosphates have been added, it is ]ir(ibable that some of the soluble phos- 

 phoric acid will furtlicr coiiibinc with lime, in which condition it may 

 be expected to bo MORE READILY AVAILABLE to plants llian 

 would have been the ca.se had the lime been absent and a more favor- 



• Experiment Station Rcporla. 



