34 
with a smaller amount of lime the iron would not be rendered unavyail- 
able so quickly. 
It is very doubtful if treatment with iron salts would render pine- 
apple growing on calcareous soils commercially successful, as the 
repeated: treatments with iron would be expensive and the crop 
would not be equal to that secured from soils naturally adapted to 
pineapples. 
ASH CONTENT OF GREEN AND CHLOROTIC LEAVES. 
An examination was made of the ash content of green and chlorotic 
leaves. Since the chlorosis is evidently caused by a disturbance in 
the mineral nutrition of the plant, it was thought that the difference 
between the ash content of green and chlorotic leaves ought to make 
evident in what the disturbance consists. As the ash varies con- 
siderably with the age of the plant, only plants of the same age were 
taken for the comparative analyses. 
The analyses were made according to the official methods of the 
Association of Official Agricultural Chemists for plant ashes, with 
two exceptions. As the content of lime in all the ashes far exceeds 
that of phosphoric acid, no addition of calcium acetate was made 
previous to the ignition, which took place over a very low flame. 
Check analyses were run on samples ignited with and without cal- 
cium acetate and it was found that there was no loss of phosphoric 
acid in the ignition without calcium acetate and that the lime could 
be determined more accurately without the acetate addition. The 
determination of potash was made according to the method given by 
K6nig?; as for the determination of potash alone in these ashes, this 
method was more accurate. 
The plants from experiments I, II, and III (see pp. 23-25) were 
analyzed at the close of the experiments. As the experiments were 
run in series of five, equal samples of the dried substance of each of 
the five plants were combined to make a composite sample for the 
analysis. The analytical results in the table below are thus an 
average of the five plants grown under like conditions. All the plants 
in this table were 10 months old and the plants in each experiment 
had received the same amount of fertilizer. The only factor tending 
to create a difference in the respective ashes was the amount of 
calcium carbonate in the soil. 
In the table there are three series of comparative analyses—plants 
grown in a sandy soil, in a loamy soil, and in a soil rich in humus. 
In each series there are three analyses—plants grown in the soil 
without calcium carbonate, in the soil plus 30 per cent of calcium 
carbonate, and in the soil plus 50 per cent of calcium carbonate. 
1J. Konig. Die Untersuchung landwirtschaftlich und gewerblich wichtiger Stoffe. Berlin, 1906, 3. 
ed., pp. 29, 30. 
[Bull. 11] 

