68 SOILS 



and not till then, will this material (in any considerable 

 quantity) pass into solution and into available plant food. 

 Of course, the same effect may be accomplished in 

 other ways and in quicker ways : by employing acids, for 

 instance. And this is done, and on a very large scale in 

 many of our commercial fertilizer factories. The huge 

 crushers take the rocks as they go from the beds in the 

 earth, they twist and turn and roll and pound them until 

 they are broken into pieces ; and then the dissolving by 



GETTING READY FOR COTTON 

 Cotton lands need good tillage and humus more than fertilizers 



sulphuric acid follows. Before this the ground rock re- 

 sisted ; feebly, now, a part of it gives up and becomes 

 plant food available plant food. 



In this instance man's contrivance has done more in a 

 week than Nature, unaided, would be able to accomplish 

 in a century. With her own acids, man sometimes re- 

 quires Nature, herself, to do his will. After all, this form 

 of plant food as it exists in the soil is not for the present 



