AGRICULTURAL TEXT-BOOK. 



31 



Schubler gives the following table of the relative absorbing power of 

 soils : 



Thus, while sandy lands may suffer from long continuance of 

 dry weather, a neighboring field abounding in humus may ab 

 sorb sufficient moisture from the air to serve all the requirements 

 of vegetation. 



108. The power of saturation by water, and the retention of 

 moisture, vary in the same manner, and nearly in the same 



109. Another important physical property of soils, is their 

 power to absorb oxygen from the air. 



According to Schubler : 

 Grains. Cubic inche.v 



1,000 Siliceous snnd, in a wet state, absorbed oxygen, 0.24 



1,000 Sandy clay, - - * - 1.39 



1,000 Loamy clay, .... ].G5 



1,000 Brick clay,&quot; - - - - 204 



1.000 Gray pure clay, .... 2 29 



1,000 Garden mould, .... 2.60 



1,000 Arab e soil, ..... 2.4.3 



1,000 Humus, - - - - 304 



Soils lose, in drying, the property of absorbing oxygen from 

 the air, but regain it in the same proportion as before, on being 

 moistened. The action of organic manures, and the production. 

 of carbonic acid, depend on the existence of oxygen in the soil ; 

 and, in practice, the difference is very great. Every farmer 

 knows how little good is effected by his barn-yard manure on a 

 crop in a very dry season, compared with a moderately wet one. 



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