CARBONATE OF LIME. 109 



The same sun shone on all of Illinois during these 

 centuries, the same rains fell, prairie grasses grew 

 over most of the land. Where carbonate of lime was 

 abundant in the soil humus was created, and the 

 land grew black and rich. Where there was de- 

 ficiency in carbonate of lime fertility could not 

 gather. It is a most significant lesson. 



Carbonate of lime then conserves humus and fer- 

 tility in some way. It makes a healthful home for 

 the bacteria that help plants. What else does it do? 



Stops Waste of Nitrogen. Carbonate of lime 

 stops waste of nitrogen. Decaying vegetation or 

 humus in the soil creates nitric acid ; this is readily 

 soluble, and unless taken up by plants soon leaches 

 away and is gone. Should there be a sufficient sup- 

 ply of carbonate of lime present, however, the tiny 

 drop of nitric acid seeking to escape touches a par- 

 ticle of carbonate of lime, the two unite and form a 

 calcium nitrate. This locks up the nitrogen and holds 

 it in the soil. It is practically impossible to store fer- 

 tility in soils deficient in carbonate of lime. Soils hav- 

 ing a large store of carbonate of lime, on the other 

 hand, will accumulate nitrogen, and hold it for many 

 years, giving it up again when called upon by the 

 plants. I have seen astonishing instances of this upon 

 Woodland Farm. Certain fields have had on them at 

 one day old home sites, where the first settlers built 

 their little cabins and had their gardens and cow lots. 

 For forty or fifty years these small settlements have 

 been swept away, and nothing remains now to tell 

 their location excepting th fragments of brick or 



