MEASURING PLANT FOOD REQUIREMENTS 161 



TABLE NO. XIV. Continued. 



COTTON FOLLOWED BY A COVER CROP, FOLLOWED BY CORN AND 

 COWPEAS, FOLLOWED BY OATS OR OATS AND VETCH, FOLLOWED 

 BY COWPEAS, FOLLOWED BY A COVER CROP. 



The plan as outlined serves to show a simple fertilizer 

 test in connection with a three-year rotation; it may be 

 enlarged or modified to cover any desired scope or condi- 

 tion, or it may be used simply to test a single crop. In 

 making fertilizer tests, the most approved agricultural 

 methods for maintaining fertility should be followed, unless 

 the object of the experiment is to determine the plant food 

 requirements under a one-crop system. 



The individual farmer should avail himself of all the data 

 issued by his own and neighboring Experiment Stations, 

 and it will often prove profitable for him to conduct simple 

 tests himself. He should be familiar with the plant food 

 content of his various soil types, procured by soil analyses, 

 for this shows the amount of potential plant food in his 

 soil, and he has at his command the various agencies already 

 discussed for bringing this food into availability. 



