8 MANURING EXPERIMENTS wtth paddy rice (third year). 
without phosphoric acid ; assuming 20% of the phosphoric acid 
of superphosphates to be assimilable to the first crop, the stock 
available in the soil per tan would be equivalent to 3.6 resp. 3.9 
kilogrms. of phosphoric acid soluble in water, and would suffice 
only for the production of 1.2 —1.3 koku of hulled rice. 
Lastly, with reference to the consumption of potash from the 
soil our researches gave the following results : 
Potash in the dry 
matter of the 
whole crop. 
Potash in 
the 
manure. 
Potash consumed 
from the soil, resp. 
soil and manure. 
grms. 
grms. 
grms. 
Unmanured, 
188g. .0.705 
1.89 
0 
1.70 
»» 
1890. .0.886 
4.65 
0 
4.00 
1891..0.595 
2.64 
0 
2-39 
Without potash, 
1889. .0.429 
4.78 
0 
4-59 
5 j n 
1S90. .0.386 
4-3 2 
0 
3-67 
» 
1891.. 0.34t 
3-14 
0 
2.89 
Complete manure, 
188g . .0.710 
9.25 
g.18 
9.06 
»4 5 » 
1890. .0.770 
IO.I7 
9.18 
g.52 
»? î Î 
1891. .0.660 
7-85 
8-33 
7.60 
The percentage content of the crops, as well as the total 
quantity of potash extracted from the soil, clearly shows that in 
consequence of the continued cultivation of rice the stock of 
assimilable potash in the soil diminished so far that maximum 
crops could no longer be produced in 1890 and 91 unless this 
nutrient were supplied in the manure. Assuming according to 
our preceding researches (bulletin No. 8) that of the assimilable 
potash of the soil 50% can be consumed by the rice plants, we 
find the total assimilable potash to have amounted : 
in 1889 ... 
„ 1890 ... 
» 1891 ... 
per frame 
... 9.18 grams. 
7-34 » 
... 5.78 „ 
per tan 
11.0 kilogram. 
8.8 
6.9 „ 
