226 REPORT ON Crop PRODUCTION OF THE 
Table XI shows the relation between the quantity of plant 
food needed for the increase of crop and that applied in the 
fertilizers. 
TABLE XI.—FERTILIZER ELEMENTS IN FERTILIZERS AND IN CROP INCREASE 
PRODUCED. 
NITROGEN. PHOSPHORIC ACID. POTASH. 
ferti- Applied Applied Applied 
lizer per In in- Applied in po- Inin- Applied in po- Inin- Applied in po- 
acre. creased. in L.I.  tato creased inL. I. tato creased inL.I. tato 
yield. formula. formula. yield. formula. formula. yield. formula. formula. 
500 10.9 20 35 3.4 40 20 12.2 50 50 
1000 20.4 40 70 6.4 80 40 23.2 100 100 
1500 25.5 60 105 8.1 120 60, 29.1 150 150 
2000 28.3. 80 140 8.9 160 80 32.7 200 200 
These figures make it very evident that, with the exception 
of the nitrogen, the fertilizers in quantities of 1,000 lbs. or over 
furnished the three important ingredients in great excess over 
what the crops used, and in much greater excess, nitrogen 
included, over the needs of the crops above what the soil could 
supply. Such facts as these force us to the conclusion that crop 
production is largely dependent upon factors other than the 
mere supply of plant food. If, therefore, Long Island farmers, 
or any others, for that matter, are to apply commercial fertilizers 
in such generous amounts, they must give careful attention to 
other soil conditions, such as water and humus supply if they 
are to reap adequate returns. 
THE KIND OF FERTILIZER. 
The favorite fertilizer formula with Long Island farmers for 
potato growing has for some years been nitrogen 4 per ct., phos- 
phoric acid 8 per ct., and potash 10 per ct. The formula more 
nearly conforming to the proportions of the three ingredients in 
the potato crop is nitrogen 7 per ct., phosphoric acid 3 per ct., 
and potash 10 per ct. Table XII shows the results of an experi- 
mental comparison of these two formulas for four years. 
The Long Island formula appears to have been uniformly 
more efficient than the potato formula. As the former contained © 
as much potash as the latter, and more nitrogen, its superiority 
