l6 MANURING EXPERIMENTS WITH PADDY RICE (THIRD YEAR). 
Phosphoric Acid. 
Grms. per frame 
I. 
2. 
3 - 
4 - 
5 - 
6. 
Freshly 
manured. 
In the whole crop of 1891 .. 
1.08 
i-39 
i.61 
° 
! 00 
2.10 
2.03 
2.62 
In the crop of 1891 produced 
without phosphoric acid.. 
o.g6 
o.g6 
0.06 
o.g6 
0.96 
0.96 
0.96 
Consumed from the residual 
phosphoric acid . 
O.I2 
0 43 
0.65 
0.84 
1.14 
1.07 
1.66 
Residual phosphoric acid in 1891 
3-65 
6.99 
10.38 
I3-9 8 
18.09 
2!-73 
— 
Consumed, per cent of this 
residue . 
3-29 
6.15 
6.26 
6.01 
6.30 
4.92 
Now summing up the proportions of phosphoric acid con¬ 
sumed from the sodium phosphate applied in 1889, we arrive at 
the following figures : 
i. i. 3. 4. 5. ^6. 
Phosphoric acid applied per 
frame in 1889, grms.. .. 4.59 9.18 1377 18.36 22.95 27.54 
Consumed, per cent of the 
phosphoric acid originally 
applied in 1889.20.5 22.8 21.1 ig.4 15.9 15.4 
» i8go.— — 3.5 4.5 5.4 5.7 
„ 189 1. 2.6 4.7 4.7 4.6 5,0 3.9 
in the three years .. .. 23.1 27.5 29.3 28.5 26.3 25.0 
These results clearly illustrate the well-known fact that easily 
soluble phosphates display their chief action soon after applica¬ 
tion, while in subsequent seasons the crops no longer derive any 
considerable benefit from them. It is probable that the experi¬ 
ments under discussion represent an extreme case, as they were 
made with an extremely soluble phosphate and on a soil very 
rich in hydrated sesquioxides of iron and aluminium, and conse¬ 
quently endowed with an extremely high absorptive power, in 
which medium the phosphoric acid applied is gradually convert¬ 
ed into basic compounds not easily assimilable by plants. 
III. Series. After-Effect of Various Phosphates. 
(Second Year). 
This series was commenced in 1890 on 57 plots with 9 
different kinds of phosphates, the composition and description 
