42 MANURING EXPERIMENTS WITH PADDY RICE (SECOND YEAR). 
Finally, it may be of some interest to calculate how much 
nitrogen and phosphoric acid was required in the preceding 
researches for the production of one koku of hulled grain. 
The results are thus : 
A. Nitrogen. 
Kwamme. 
Kwamme. 
Steamed bone dust 
...r.13 
Peruvian guano . 
•i*43 
Hoshika . 
... 1.20 
Night-soil . 
• 1-57 
Shimekasu . 
...i. 21 
Shöyu cake. 
• 1-59 
Blood meal . 
Rape cake, fresh. 
• 1-59 
Crude bone dust ... 
Ammonium sulphate .. 
.1.62 
Shöchü cake 
•••i-35 
Farmyard manure 
.1.90 
Horn meal . 
...r .39 
Rice bran, unfermented. 
2.99 s * 
B. Phosphoric Acid. 
Superphosphate. 
Kwamme. 
. °-75 
Precipitated calcium phosphate 
. 0.70 
Bone dust . 
.1.28 
Thomas phosphate . 
. 141 
Peruvian guano. 
.2.19 
Bone ash . 
.2.66 
Phosphorite. 
.8.28 
These figures have reference only to the increase of hulled 
grain over that quantity which the soil is capable of producing 
without any nitrogenous or phosphatic manure. In medium 
soils the supply of nitrogen to the crops from the residues of 
previous manures and from constituents of the soil itself, as 
well as from natural sources such as irrigation, rain, and 
fixation of atmospheric ammoniacal and nitric compounds is 
generally very large, exceeding considerably the amount of 
nitrogen applied in the manure. Compared with the nitrogen 
supply there exists, especially in Japanese soils, which never 
23 In the fermented state about 1.60 kwamme of nitrogen. 
