CROPS AND SOIL IMPROVEMENT 



The ill-effects usually attributed to acid phos- 

 phate are not due in any great degree directly to 

 the sulphuric acid used in its making, but to the 

 bad farming methods that so often attend its use. 

 When the need of commercial fertilizers is first 

 recognized, acid phosphate seems to meet the 

 need. The soil's store of available phosphoric 

 acid gives out first, and this fertilizer brings a new 

 supply. If the available potash is in scant 

 amount, the acid phosphate helps in this direc- 

 tion by freeing some potash. The phosphoric 

 acid has peculiar ability in giving impetus to the 

 growth of a young plant, and that enables it to 

 send its roots out and obtain more nitrogen than 

 it otherwise would do. The farmer thus may 

 come to regard it as a means of securing a crop, 

 and there is neglect of manure and clover. If a 

 field is thin and fails to make a sod, there is no 

 immediate compulsion to use manure or to grow a 

 catch crop to get organic matter, but the field is 

 cropped again with grain. Soon the supply of 

 humus is exhausted, the soil lies lifeless, and the 

 stores of available nitrogen and potash are in a 

 worse depleted state than formerly. 



The fault lies with the method. The phos- 

 phoric acid in the acid phosphate was needed. 



[182] 



