1 Nov., 1902.] QUEENSLAND AGRICULTURAL JOURNAL. 365 
The amount of ash found in the pith is also very high, and a special 
feature in the composition of this ash is presented by the high percentage of 
lime and potash and the very small amount of phosphoric acid. This low 
amount of phosphoric acid, found in the tree, would at once indicate that the 
bottle-tree is not a highly valuable food for cows in calf or for young growing 
stock, since phosphoric acid is the most important constituent of bones. 
A comparison of the analysis of the bottle-tree with the analyses of 
other fodder plants indicates that, as a food, this material may be classed in its 
value with mangel-wurzel and cattle cabbage, but it is also found much superior 
to prickly pears. : 
1+ must be borne in mind, however, when studying the analyses of vegetable 
growths used as fodder under exceptional circumstances, that one does not look 
so much for an actual fattening value, but rather for indications as a food to keep 
the stock alive. : a 
J. C. BRUNNICH, Chemist. 
W. MAXWELL, Director. 
Department of Agriculture, - 
Chemical Section of Feed Stuffs and Products. 
HOW THE PEA GIVES US NITROGEN. 
The Florida Agriculturist takes the following from Farmer and Fruit- 
grower :— 
It has long been known that plants belonging to what botanists call the 
family of Leguminosx had in some way the power to acquire and use nitrogen 
that did not exist in a combined state in the soil. Some asserted that the 
plants absorbed the nitrogen from the air by means of their leaves. But later 
investigations have shown that the work of nitrogen-catching is done by the 
peas or clover or other legume (a legume is a plant the fruit of which is a 
legume or pod, hence the name for all the family is Leguminose or pod- 
bearers). The real work of getting the nitrogen, of which the air is largely 
composed in the form of a free gas, is done by certain microscopic plants that: 
attach themselves to the roots of this class of plants as parasites. The para- 
sitism, however, in this case is not a harmful one, since the little organisms that 
feed on the nitrogen gas that penetrates the soil give more to the roots than 
they take, and the process is a sort of symbiosis, or living together for mutual 
advantage, rather than a parasitism that is harmful. These little plants, con- 
sisting of single cells of living matter, have the wonderful power, that no green 
plant has, of feeding on the nitrogen gas, and, through this feeding or oxidation 
of the nitrogen, forming nitric acid. 
Now when an acid is formed in the oil it at; once finds some base, such as 
line, potash or magnesia, and is transformed into what is called a salt of these 
substances, and the result in this case is the formation of nitrates of potash 
lime of magnesia, which green plants like the clover can at once absorb and 
use in their growth, for it has been proved that all forms of nitrogen in the 
soil must be changed into nitrate before the green-leaved plants can use it. In 
this process of the formation of nitrates by the little plants that exist on the 
roots of the pea, the pea is enabled to take up and store away in its erowth a. 
large part of the nitrates formed, and the soil also gets fixed in it the same 
form more than the pea takes up, and the nitrogen content of the soil itself. is 
increased. 
The Gain in Saving Hay.—Now, when the pea crop is harvested as hay, a 
large part of this nitrogen is taken in this hay. But in feeding the hay, by far 
the larger part is recovered in the droppings of the stock, and, if this is 
carefully saved and applied, we lose but a small part of the manurial value 
of the pea, while at the same time we can get the feeding value to make a 
profit out of in the stock. Another part remains in the roots in the form 
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