DEPTH OF PLOWING 53 



Take five potfuls of soil from the field and test for 

 the elements required to grow the crop. In each of 

 these pots plant a few seeds of the crop desired to be 

 grown. To the first pot add nothing, to the second, a 

 quarter teaspoonful of sulphate of potash, or if that is 

 not obtainable use a teaspoonful of wood ashes. To the 

 third pot put a combination of the phosphate and 

 potash, to the fourth a quarter teaspoonful of sodium 

 nitrate or ammonium sulphate, and to the fifth a com- 

 bination of acid phosphate, sulphate of potash and 



Whether the ground is plowed deep or shallow the condition of the 

 earth shown in this cross section of a plowed field must obtain before the 

 seed bed can be made a success. Deep plowing often shows a good 

 surface and hides a bad furrow bottom. 



sodium nitrate. This sort of test is not, strictly speak- 

 ing, scientifically accurate, but it is close enough to show 

 anyone which of the three principal plant food elements, 

 phosphorus, potash and nitrogen, are lacking in the soil. 



If the plant in the first pot refuses to grow, it is plainly 

 evident that the soil is lacking in plant food elements. 

 The growth of the plants in each of the pots will signify 

 in what the soil is lacking and what will be necessary to 



