January 2, i888.j THE TROPICAL AGRICULTURIST. 
433 
MCE SOILS AND RICE MANURES. 
The following contribution to tropical agriculture 
written for us by Mr. John Hughes, r, c. s., is well 
worthy of attention, especially by the Director and 
his Department of Instruction : — 
Rice is certainly one of the most generally diffused 
and useful of the grain crops, and probably sup- 
ports the largest number of the human race. 
Not only is it produced in large quantities in 
India, China and the east generally, but we find 
it extensively cultivated under the most favourable 
conditions as regards irrigation in the southern 
portions of Italy, Spain and Portugal, as also in 
parts of tho West Indies, Central America and 
the United States. It would therefore appear that 
provided there is a sufficient supply of water, 
rice can be produced on all kinds of soils and 
under vaiious conditions of climate. Doubtles if 
inquiry were made, this would be found to be 
practically the case ; at least so far as the 
writer's own experience, gained after visiting 
certain rice districts in the south of Spain and 
Portugal, and subsequently making a careful 
analysis of the soils. The most essential thing in 
the soil itself is that it should be in a minute 
state of division so as to supply an abundant 
source of soluble silica which is so necessary 
in the formation and successful growth of the 
straw, and wihout which it would be. quite 
useless to expect to obtain a good crop. 
In other words it is very much the same as we 
know is fully recognized in regard to wheat, namely, 
that the best crops are produced on naturally still' clay 
soils which contain plenty of available silica and 
potash. Indeed all good rice soils must be stiff ones, 
so much so that frequently portions of the soil become 
when pressed and dried as hard as bricks, and this 
faot leads us to understand how necessary a suffi- 
cient supply of water must be, not only in the 
preparation of the land for the seed, but during 
the early period of growth, during which, unless the 
soil was kept in a soft pliable statu, it would be 
impossible lor the delicate roots to permeate it in 
search of plant Jood. In 1873, certain doubts hav- 
ing been fiequently expressed as to tho value of, 
or necessity lor, irrigation in the growth of rice, a 
great number of interesting experiments were car- 
ried out in the Midnapore district by Mr. Apjohn, 
the general results being that the crops irrigated 
from tho beginning of the season exceeded in value 
the altogether unirrigated ones by Rlfi per acre, 
the value being calculated from the selling price 
of the paddy and straw on the ground. 
In making this comparison it is only fair, however, 
to remember that the year 1873, being one of de- 
ficient rainfall, was decidedly favourable to the crops 
irrigated by means of canals, and unfavourable to 
the crops grown without the aid of additional water 
artificially supplied. It may, however, be safely 
inferred that in bad Reasons the canal-irrigated 
crop will be four or five times better than the 
uiiirrigalod ono, and that in ordiuary years the 
former will still compare favourably witli the latter 
and yield a return equal to one-fifth or one-sixth 
more, an increase which perhaps may be considered 
small when merely one acre is considered, but which 
becomes immense and of vital importance when tho 
area of cultivation is reckoned in hundreds of thou- 
sands of acres. These aro the views put forward by 
Simmomls in his excellent work on Tropical Apicul- 
ture, and they arc worthy of serious consideration 
when we look into the question of the annual food 
Mupply ol tho notives of India and the recurrence of 
famine as the result of long continued drought. 
In the extension of canals for irrigation purposes, 
and in tho introduction of improved inuchinery 
(or preparing the rice for market, Europoau aid 
under Government supervision can be most 
profitably employed. In the actual tillage of 
the ground probably the natives are as skil- 
ful, and certainly more likely to raise crops 
with profit, than the majority of English residents 
fresh from home who frequently have had no pre- 
vious practical agricultural knowledge. 
We should always bear in mind that the local 
customs for treating land and raising crops like 
rice have grown out of the accumulated know- 
ledge of many past generations, and we should 
treat them with that deference and respect which 
well directed age should always command. 
Leaving then the extension of canals and the 
construction of suitable tanks for the storage 
of water to the careful consideration of the re- 
sponsible Government authorities, and the intro- 
duction of improved appliances for threshing the 
paddy (rice in husk) and preparing the rice for 
market to the inventivo genius of our agricultural 
implement makers, let me proceed to place on 
record a contribution to the examination of the 
chemical composition of rico soils with a few re- 
marks respecting the kind of manure which has 
been found after some years of trial most suitable 
for application, and to yield the most remuner- 
ative results. 
As already stated, rice is doubtless grown on a 
great variety of soils, and the two following an- 
alyses are only introduced as examples of the 
difference that obtains in their chemical composition. 
Many others could be produced if the soils were 
available for examination : — 
Analyses or Rice Soils in Partially Dmed State. 
No. 1. No. 2. 
Prom Valen- From near 
cia in south Lisbon in 
of Spain. Portugal. 
Water .. 7'11 7-34 
* Organic and volatile matters 6 55 8'34 
Oxide of iron . . 3 91 P30 
Alumina . . 3 61 5'26 
Lime . . 21-04 trace. 
Magnesia .. 2-21 (34 
Potash . . "65 '49 
Soda .. -03 -41 
Phosphoric acid .. -17 '09 
Sulphuric acid .. *17 -17 
Carbonic acid .. 15 79 "53 
Chlorine .. not made -08 
Insoluble siliceous matters (in 
a very fine state) .. 38-76 72-65 
100 00 100-00 
• Containing Nitrogen .. -180 -233 
Now both these samples were in a very line me- 
chanical condition, and the soil to the touch was 
soft and free from coarse sand. The silicates 
were in a form readily assimilated by the roots 
of the crop. 
Rut while one soil (2) showed only a trace of 
lime, and in this respect probably resembles most 
of the Ceylon paddy soil -, the other contained 21 
per cent of lime, equal to about 37 per cent of 
carbonate of lime as existing in the soil. 
15oth specimens are specially rich in potash as wo 
should expect from their clayey nature; the Spanish 
soil containing the most, namely -65, as against 
•19 in that from Portugal. In tho matter of nitrogen, 
however, there is a reverse, the Lisbon one being 
somewhat richer, though both soils are deficient in 
this important constituent of plant food, and, as 
we shall presently see, receive artificial supplies in 
tho form of mauuro in order to produce good crop-. 
In phosphoric acid the Spanish soil is again 
tho richest, '17 as against -09, but phosphate 
have to be supplied like nitrogen by yearly appli- 
cations ol come phospuutic manure. 
