156 What Fertilizers to Use. 
deeply, for there have been cases of moisture near the surface, 
and drouth below. 
WHAT FERTILIZERS TO APPLY TO FRUIT TREES AND VINES. 
A discussion of this subject from a chemist’s point of view 
is beyond the scope of this volume. The reports of the Univer- 
sity Experiment Station at Berkeley are rich in details of the 
researches and deductions therefrom by Dr. E. W. Hilgard, who 
maintains the position that the most intelligent and economical 
choice of fertilizers is to be made alter ascertaining by analysis’ 
in what constituents the soil is deficient and in what it is well 
supplied. Applications made in conformity with suggestions 
based upon analysis have proved very satisfactory. But as soils 
vary within narrow limits of area, there must be analysis for. 
each soil in question. 
Approaching the matter of choosing fertilizers without soil: 
analysis, the method by local trial is open. In this recourse 
there is danger of error, as pointed out by Dr. Hilgard, arising 
from local differences in soil and subsoil, and must be checked 
by several check plots so interposed between the others as to’ 
not only check them by direct comparison, and to prevent the 
washing of fertilizers from one fertilized plot to another, but 
they must also be compared, first of all, among themselves, to 
determine what is the normal product of the unfertilized land. 
It will frequently be found that these unfertilized check plots 
differ more widely between themselves than do the fertilized ones 
from them or from each other. It usually takes several seasons 
to come to definite results. 
From these statements it must appear that the prescription 
of fertilizers is not an easy matter. Disappointments will natu- 
rally be encountered, but unquestionably the advantage is on the 
side of patient trial and wise investment in fertilizers honestly 
made and honestly sold. One of the most manifest needs of the 
State is a fertilizer-control law which shall provide surety to the 
purchaser of the purity and identity of the materials which ate 
offered for sale. Efforts to secure the enactment of such a law 
have been repeatedly made without success. Active and united 
effort to secure a wise law alone can succeed. 
Though the deficiencies of the soil, as learned by analysis, 
or by practical test, must be the basis of prescription of fertiliz- 
ers, the analyses of fruits, as showing the special needs of the 
plants, are of the highest importance. The following analyses 
oj the different fruits, containing, in each case, skin, pulp, and 
seeds, are almost entirely from California-grown specimens. and 
are supposed to represent an average composition of the fruits 
named. 
