115 
much as one half ration of potash and never over one-fifth ration of nitro- 
gen, while the plot experiments have undertaken to supply full rations for 
a full crop, which is fully double an average crop. 
The quantities of fertilizer used in the plot tests mentioned above 
seem quite absurd to the American grain grower, yet they are very con- 
servative compared with another set inaugurated at about the same time 
in which 2,000 pounds of acid phosphate, 600 pounds of sulphate of potash 
and 600 pounds of sulphate of ammonia per acre were used, or with an 
extensive set of orchard experiments in which the plans called for the 
application of 40 pounds of muriate of potash with corresponding amounts 
of nitrogen and phosphates to each two year old tree. 
In the case of the plot experiments conducted for the purpose of de- 
termining the value of the different plant foods, the excessive quantities 
have often caused a profit to be shown for only the particular plant food 
which was most deficient, while if more reasonable quantities had been 
used each would have shown a profit. It is not unusual to find reports 
of these experiments that recommend the use of a single plant food as all 
that is necessary merely because it was the one that chanced to give the 
largest profit. 
As compared with this line of plot experiments with full rations we 
may, perhaps, devote a moment to results of plot experiments where 
amounts and formulas generally used in farm practice were taken as a 
basis. 
On a typical worn clay wheat land an experiment was undertaken on 
the basis of 300 pounds per acre of goods containing nitrogen 3 per cent, 
available phosphoric acid 10 per cent and potash 6 per cent, each element 
being omitted in turn in the usual way. 
The following results were obtained: 
Fertilizers applied Yield, | Reduction from Omitting 
per acre. bushels — - - 
Equal to— per acre. | Nitrogen. |Phos. Acid. Potash. | All. 
; 
300 Ibs. 3-10-6.........: Ep trey Ne ep eerste a || Meee ee 
300) Ibs. 0-10-6.... 42... +. PATE | Ae wlpat sen tkss 5 
300 Ibs. 3— O-o..... fos TOPA Glo FAS 0 erence er 26.2 ara 
supribs: S—10-0. 2a. 2 Opera eet es al te 5 8.8 Brats 
MlegHe ree sc tits aces ee (A lene iol ge este poi eae | 27.3 
