20 VEGETABLE GROWING. 



the field ; then take the next four rows and withhold 

 the potash from these ; now treat four rows with the 

 usual fertilizer ; then take a third set of four rows and 

 withhold the phosphoric acid from these. While the 

 tests are being prepared, a number of strong stakes 

 are made ready to mark off eacli plot by driving them 

 securely into the ground at the first row of each test. 

 If a second dressing of fertilizer is given to the crop, 

 care must be exercised not to apply tbe element that 

 was withheld when the first dressing was made. In 

 making such a test it is almost useless io use only one 

 or two rows, as the plants will draw their supply of 

 the wanting element from the neighboring row. After 

 such a test has been made, the crop from this portion 

 should be measured carefully and compared with that 

 of the neighboring rows. Now, if the first four rows 

 show a decidedly poorer crop and the other two sets of 

 four rows are of an average production, it is plain that 

 the field needs nitrogen, but if the first and third sets 

 of four rows have fallen off, the field needs nitrogen 

 and phosphoric acid and not potash. There are sev- 

 eral gardeners in the South that have saved money by 

 testing their fields in this way. 



Another way that has been employed, but one that 

 does not tell quite as much, is to use the plots in the 

 same way described above, but in the place of using 

 two elements, use only one ; for example, choose four 

 rows and fertilize these with a nitrogenous fertilizer, 

 containing neither potash nor phosphoric acid ; then 

 leave four rows for a check ; then treat four rows with 

 phosphoric acid, etc. On vegetables either of these 

 tests are easily performed, but on fruit trees the re- 

 sults are so slow in making themselves manifest that 

 it has not proven a success. 



A portion of our land is not benefitted by the addi- 

 tion of potash, but nitrogen and phosphoric acid are 

 nearly always deficient. Nitrogen is usually present 

 in sufficient quantities in muck land, but it often needs 

 lime to put it into fit condition for plant food. 



