4 
MANURING EXPERIMENTS WITH PADDY RICE. 
Extracted by hot 
hydrochloric acid 
of the spec, grav¬ 
ity i. 15 
Extracted by hot 
concentrated sul¬ 
phuric acid. 
By treatment with 
hydrofluoric acid. 
Top 
Sub- 
Top 
Sub- 
Top 
Sub- 
soil. 
soil. 
soil. 
soil. 
soil. 
soil. 
Silica' 1 .. 
18.60 
I 5-58 
1.41 
I -55 
17.42 
22.45 
Alumina. 
17.05 
14.80 
O.7O 
0.88 
3 or 
3.06 
Ferric oxide. 
3-95 
2.68 
O.4O 
o -35 
I.4O 
1.87 
Ferrous ,, . 
4 - 7 1 
5-31 
— 
— 
— 
— 
Lime . 
O.9O 
0.80 
0.31 
0.10 
0 - 94 - 
I.OI 
Magnesia . 
0.66 
0.62 
0.12 
0.10 
O.7O 
0.79 
Potash. 
0.32 
0.26 
O.O9 
0.13 
0-33 
0.45 
Soda . 
O.ig 
0.25 
0.12 
0.16 
0.33 
0.50 
Phosphoric acid. 
0.49 
O.4O 
— 
— 
— 
— 
Sulphuric ,, . 
0.16 
0.08 
— 
— 
— 
— 
Chlorine. 
0.03 
0.03 
— 
— 
— 
— 
Total .. 
47.06 
40.81 
2.97 
3-27 
24-13 
30-13 
Undissolved, resp. undecom¬ 
posed mineral matter 
27.10 
33-40 
24.13 
30.13 
Our soil is accordingly rich in humus, compounds of iron, 
and easily decomposable silicates, but very poor in clay (hy¬ 
drous silicate of alumina). Its considerable content of organic 
matter, the low situation as a paddy field and the presence of 
much moisture throughout the year render it inclined to 
sourness and cause a considerable reduction of the sesquioxide 
of iron to protoxide. As to its deportment toward nutritive 
solutions our researches show that ammonia, and consequently 
also potash, are very strongly absorbed, the coefficients of 
absorption determined by Knop’s method were 99 for the topsoil 
and 90 for the subsoil ; phosphoric acid is retained to a still 
far higher rate. Hence ammoniacal and potassic salts, as well 
4 Including the silica dissolved by a solution of sodium carbonate, after 
the treatment with hydrochloric resp. sulphuric acid. 
