Jan. io, 1914 
Environmental Influences on Wheat 
289 
of the samples grown in Maryland was appreciably higher than that of 
the samples grown in California, while the protein of the former was less 
than that of the latter. On the other hand, the ash content of the 
Kansas samples was only slightly higher than that of the Maryland-grown 
samples, although the protein content of the former was 50 per cent 
higher than that of the latter. 
COMPARISON BETWEEN RESULTS FROM DISTURBED AND UNDISTURBED 
PLATS OF THE SAME SOIL 
Attention has thus far been directed primarily to the composition of 
the wheat samples grown for several years in each locality on each of the 
three soil plats which had been taken up in 3-inch layers and interchanged 
among the three localities. As previously mentioned, a check plat 
of equal size, in which the soil had not been disturbed, was planted each 
year in each locality, and samples from it were analyzed for comparison. 
A fear that manipulation of the soil would produce abnormal conditions, 
influencing the character of the crop, was not justified by these results 
(Table V), at least not as evidenced by the physical appearance and the 
chemical composition. The slight differences between the crops from the 
disturbed and undisturbed plats of the same soil are apparently either 
accidental or due to errors in sampling or in analysis. This is further borne 
out by the results from both the seed-exchange experiments 1 and from 
the soil-exchange experiments (pp. 278-281). It is simply a verification of 
the conclusion already drawn, that the soil factor plays but a very sub¬ 
ordinate part or is entirely devoid of influence in determining these 
characteristics in the crop. 
Such great differences exist in respect to one constituent, however, 
that they must be classed as exceptions to the rule. The percentage of 
phosphoric acid averaged 0.96 per cent in the samples from disturbed 
plats and 1.06 per cent in those from undisturbed plats, or, if expressed 
as the percentage of phosphoric acid in the ash, it is 46 and 49 per cent, 
respectively. It might seem that the undisturbed soil could give a little 
more phosphoric acid to the grain than the disturbed soil. These dif¬ 
ferences, being only slightly greater than the limit of error in analytical 
work, probably have no significance. 
CONCLUSIONS 
As is to be expected in plat work in the field, especially with such small 
plats as were used for these experiments, there are many variations in the re¬ 
sults which seem accidental, in that they can not be interpreted according 
to any definite law. There are, however, certain variations which appear 
with such regularity that important conclusions may be drawn from them. 
An inspection of the tables should show whether climatic conditions 
or soil characteristics have a strong determining influence upon the 
1 Le Clerc and Leavitt. Op. cit. 
