ON THE CULTIVATION OF INDIGO. 
379 
correct in his assumption, that “ The new 
lands, and these are in abundance, are more 
productive than those in use ?” Now, if 
we consider this extended cultivation to have 
commenced in 1823, we shall find the contrary 
to have been the case ; and that the land oc- 
cupied since that period, is not so {Productive 
as the land previously in cultivation, which 
■consists of the churs in the river and its low 
banks, rendered fertile by annual deposit — 
the further we recede from the influence of 
the inundation, the less adapted is the soil 
for the cultivation of indigo.” 
In support of Mr. Alexander’s reasoning, 
the analysis of the fertilizing principles of the 
Ganges’ inundations, by Mr. Piddington,goes 
to prove that vegetable decomposition, in 
various stages, is not the chief fertilizing 
principle of the great tropical rivers. Mr. 
Piddington observes — 
“ It is well known, that, while the tracts 
within reach of the inundation preserve their 
original fertility, the higher soils are general- 
ly and rapidly impoverishing, and this to a 
degree of which few, who have not made the 
subject one of attention, are aware. There 
are some crops which cannot be repeated on 
high soils, unless at intervals of three or 
four years ; while, on the low lands, these are 
the only ones which are, and have been, taken 
for a period beyond the memory of man. In- 
digo is a striking instance, and the most fami- 
liar one, of what is here advanced ; and it 
was w;ith a view to some improvement in the 
cultivation of this plant, that the following 
analysis was instituted. Portions of the silt, 
or mud, deposited by the inundations, were 
procured from Bansberria, near Sooksaugor, 
and from Mohutpore, near Kishnagur ; the 
analysis of each gaye, in two hundred parts. 
Silt from Bansberria. Silt from Mohutpore. 
Water, 2 2 
‘‘Vegetable mat-"] 
ter, destructible > 0.. 
by heat, 
Saline matter, 
mostly Muriate 
of Potass, .... 
“ Cai’bonate of 
Lime, 
” Phosphate of 
Lime, 
“ Oxide of Iron,. . 12 12 
“ Silex, 156 139 
“ Alumina, . . . . 6| 14| 
Total, 193| 19li 
“ Loss, 8| 
200 200 
The very unlooked for circumstance of 
only 2§ per cent, of vegetable matter being 
found in these specimens, appears to exclude 
the idea, that this is the fertilizing principle, 
or, at least, that it should be exclusively so ; 
j 0| o§ 
} 12| I6i 
} ^ 
while, on the other hand, from 6 to 8 per cent, 
of calcareous matter appearing in them, (when 
in an extensive series of experiments, on high- 
er soils, this was always found remarkably 
deficient, seldom more than 0-75 to 1 per cent.) 
points to the conclusion that the calcareous 
matter was, perhaps, the great agent, and, in 
as far as regards indigo, this was found, by 
experiment, to be the fact,; for a minute por- 
tion of lime was found to increase the pro- 
duce upwards of 50 per cent.” 
Mr. Alexander argues that the lands 
within the influence of the inundation, long 
since occupied for the cultivation of indigo, 
are annually richly manured by a process 
which impoverishes the higher lands. As the 
cultivation of indigo is advanced from the 
banks of the rivers, land is occupied which 
will not yield a produce equal to that obtain- 
ed in the soil renewed by annual deposits 
from inundation, unless the fertilizing matter 
washed away be replaced by manure. Our 
author deems it to be carbonic acid gas that 
acts as a powerful productive agent on the 
cMrs of the Ganges, and operates with the 
new soil annually deposited, in producing 
such fine indigo. The manure, when neces- 
sary, is therefore lime. The following 
shows the amount of crops for ten years. 
“ The crop of 1819, was 1.05,000 
1820, „ 72,000 
— 1821, „ 90,000 
1822, ,, 1,13,000 
— 1823, ,, 80,000 
1824, „ 1,10,000 
1825, ,, 1,43,000 
■ 1826, ,, 90,000 
1827, ,, 1.47,000 
1828, ,, 96,000 
I divide these 10 seasons into two periods, 
of 5 years each; as it is generally considered, 
that in the season 1823-24 the spur to increas- 
ed cultivation was given ; and I may add, 
that, if over production of indigo was ever 
likely to take place, the last 5 years w^as the 
period for it. In the first period of 5 years, 
the difiPerence of crops annually w’ere as fol- 
lows : — 
maunds, 
1820 the crop was less than in 1829, 33,000 
1821 ditto greater than in 1820,. . 18,000 
1822 ditto ditto 1821,. . 23,000 
1823 ditto less than in 1822,. . 33,000 
This gives the greatest difference between 
any two years, 33,000 maunds, and the average 
difference 27,000 maunds, in round numbers. 
For the next period of five years, the dif- 
ference of the crops annually were. 
