233 
tions maintained depend largely on the character p£ the soil, 
the treatment it has previously received, the climate and the 
variety of rice to be grown, but the amounts and proportions 
are regulated so as to secure in the end, to the area mentioned, 
80 pounds of available nitrogen, 80 pounds, in all, of phos- 
phoric acid, and 80 pounds of actual potash. 
In connection with the growing of Genge, it is interesting 
to note that, since the accumulation of nitrogen by the plant 
is accomplished by the symbiotic growth with its root bac- 
teria, an inoculation of soils with this bacteria becomes nec- 
essary before the crop will thrive, a law that has been found 
of equal favor in the culture of alfalfa and other legumes. 
In the making of composts, horse, cow, pig and poultry 
manures, night soils, vegetable refuse, street sweepings and 
dredgings from the rivers and canals are used. This mate- 
rial and soil and straAv are spread in alternating layers. The 
mass is worked over monthly, and after two to four months’ 
decomposition is ready for application, along with the other 
fertilizers. The composting . is always done under cover to 
prevent deterioration. The usual custom is to apply the com- 
post to the spring crop, Avhich is either wheatiar barley. The 
amount applied varies from one to five or more tons per acre. 
Frequently the compost is fortified with phosphates, or phos- 
phates may be separately applied. The rice crop, which fol- 
lows the wheat or barley, receives considerable residual 
benefit from this manuring, but, as is shown elsewhere, 
heavy additional fertilization is practiced for the maintenance 
of maximumi fertility. 
In addition to the oil cakes mentioned, some wood ashes 
and bones are used, and more recen^-ly somewhat limited 
quantities of commercial fertilizers. There are a number of 
factories for the manufacture of commercial fertilizers in 
Japan, and the products are under government inspection. A 
plant for the manufacture of calcium cyanamide is also in 
operation, but the results thus far obtained give uncertain 
promise of its usefulness in rice cultivation. Lime is exten- 
sively used, as much as four tons of quick-lime being applied 
to the acre, though this amount is exceptional. The follow- 
ing list of fertilizers used in rice cultivation was furnished, 
along with their analyses : 
