ANALYSES OF FODDERS AND FEEDING STUFFS. 83 
According to the usual custom, protein has been given as 
total nitrogen multiplied by the factor 6:25, on the assumption 
that protein contains 16 per cent. of nitrogen. As has been 
repeatedly pointed out, however, this factor is only approxi- 
mately correct, for the reasons given on page 39 of the present 
Report. 
DHSTS. FOR NITRATES IN FIELD CROPS. 
In the experiments made by the Station on the effects of ni- 
trogenous fertilizers upon the composition of field crops, it has 
been found that in such crops as corn and various grasses, the 
percentage of nitrogen in.the plants increased as the nitrogen 
in the fertilizers was increased. According to the usual method 
of estimating the protein of the plant from the amount of nitro- 
gen determined, the experiments thus apparently indicated that 
the increasing of the nitrogen in the fertilizers increased the 
proportion of nitrogenous compounds (protein) in the crops. 
The question arose whether the total increase in the nitrogen 
of the plant actually represented an increase in protein, or 
whether some of the nitrogen of the fertilizer, taken up by the 
plant in the form of nitrates, was retained in its tissues as such 
without being transformed into organic nitrogenous compounds 
of the plant. This has sometimes been found to be the case. 
Tobacco frequently contains considerable quantities of nitrates, 
and the quantity present has been found to increase with the 
increase of nitrogen in. the fertilizers.* Large quantities of 
nitrates have also been found in corn grown on especially rich 
soil.t It might thus be possible that the corn and grasses 
grown on the plots or in the pots supplied with large quantities 
of nitrogenous fertilizers would contain appreciable amounts 
of nitrates. To get some light upon this question some of the 
plants grown in the Station plot and pot experiments were 
tested for the presence of nitrates. 
With one exception all the samples tested were from the 
crops grown on plots or in pots supplied with the ‘‘full ration’’ 
of nitrogen, that is, nitrogen at the rate of 75 pounds per acre. 
The samples taken from the pot experiments were all from the 
pots with nitrate of soda; those from the plot experiments were 

* See, for example, investigations reported in Conn. Sta. Rpt. 1896, pp. 322-333; also 
North Carolina Sta. Bul. 122. § 
+ A striking case has been reported in Kansas Sta. Bul. 49. 
