636 
the: tropical agriculturist. 
[MArcH 2, 1891. 
30 bushels of beans wilh their straw take up 81 lb. of 
potash per acre. 
30 bushels of wheat with their straw take up 28 lb. of 
potash per acre. 
The astonishing fact is noted that after eight years 
removal of crops the final crop was rather larger 
where no potash had been applied than where 500 
lb. of its salts had been annually applied. And yet it 
would not be wise to conclude that because no effect 
was produced at Rothamsted that potash salts are 
therefore not useful. It would be equally foolish to 
think because a great result should be obtained at 
Rothamsted we might expect the same anywhere. 
Bach farmer must be au experimentalist for himself, 
and hitherto we have not seen much evidence of the 
use of potash salts as manure for ordinary soils, such 
as we have seen in case of phosphatic and nitrogenous 
manures. They are most likely to be effective on the 
lighter classes of land. 
Nitroobnous Manures.— The two best known mem- 
bers of this group are nitrate of soda and sulphate of 
ammonia auU most of the other nitrogenous manures 
are refuse materials from animal bodies or from seeds. 
Such are all the guanos, blood, wool, fiah and flesh and 
cake manures. The efficacy of nitrogeneous manures 
appears to be due to two facts. First that nitrogen 
in au available form exists in very small quantities 
in the soil, and, secondly, that it is required in pro- 
portionately large quantities by croxjs. The total 
amount in the laud may in good fields be taken in the 
toj) nine inches as 0T5 or one-tenth of the amount of 
potash. Nitrogen is available chiefly in the form of 
nitrates, and these are much more liable to wash 
through the soil than are potash salts. Finally, 
nitrogen is removed from the farm in saleable crops 
and in the bodies of animals in larger quantities than 
potash, which is largely returned both in root crops 
and straw to the land. There may be other reasons, 
but these suflioiently account for the great effect pro- 
duced by nitrogenous dressings of all kinds. So rapid 
is their effect that it has been called “stimulating” 
although without sufficient reason. The crops seem to 
hunger for nitrogen and always present a yellow and 
starved appearance when it is deficient, A rank dark 
green appearance always accompanies a full, or over 
full, stock of nitrogen in the soil. It is to the grasses 
including the cereals, that these manures are most 
useful. But wherever leafy growth is desired as in 
the cultivation of cabbages and rape nitrogen in the 
form of nitrates may bo apislied with success. The 
leguminous crops, beans, peas and clover are not so much 
benefited by direct dressings, but they require the land 
to be rich in nitrates, notwithstanding. The absolute 
necessity of nitrates for the cereals has been amply 
proved. Wheat appears as if it could be grown con- 
secutively for almost any number of years, on the 
same land, if only plenty of nitrates are added. 
Nitrates, no doubt, if used alone, tend to exhaust 
the other constituents of plant food if the produce 
is sold off the farm. If, on the other hand, the produce 
is consumed at home — or if foods for stock and other 
manures are purchased in liberal quantities there is 
no fear of exhaustion. So important are they, that 
some times it appears as though the entire science 
of manuring consists in adding nitrates to the soil. The 
elfe.t is, however, greatly increased if phosphates and, 
in some oases other mineral manures are added with 
the nitrates so that heavy as the crops are which 
may be grown with nitrate of soda, they are eclipsed 
by a judicious use of nitrates and mineral substances 
combined. In applying nitrates we prefer to use them 
in organic combination wherever possibe. Nitrate of 
soda and sulphate of ammonia are both exceedingly 
useful but are subject to washing through the soil 
by rain — the first immediately, and the second more 
gradually as nitrification proceeds. They act rapidly 
but the effect is not seen after the first season. When 
nitrogen exists in animal or vegetable matter its 
action is slower, more uniform, and is continued for 
an indefinite length of time. Farmyard manure is au 
example of this action so also are rapo cake b'ood 
manure, shoddy, guano and many other substances. 
Such animal refutes can however hardly bo classed 
with artificial manures, and we therefore postpone 
their further consideration. 
Salt. — Salt is a cheap material which may be 
employed with good effects upon coarse rank pastures 
aud produces the best effects when mixed with lime. 
Five hundredweight of salt and three to five tons of 
lime applied in February or March to such rank grass 
land tends to produce a finer herbage. Salt may also 
be used as a dressing for wheat at the rate of about 
5 cwt. per acre. Dr. Griffith says salt eradicates 
couch on land infested with it. It this is the case we 
have an additional excellent reason for applying it. 
It is also a good dilutent for the better distributing 
of nitrate of soda and is said to check the disposition 
to develop too much straw which has been observed 
after nitrate of soda on wheat. It is also considered 
by many persons to strengthen the straw of cereal 
crops and prevents lodging of the crop before harvest. 
It also destroys slugs arid snails and is distasteful to 
insect life generally. It in this respect resembles soot 
which is one of the best applications for land affect- 
ed with these iiests . — Agticultwol Gazette. 
The Plants of the Andamans. — Dr David Prain, 
Curator of the Herbarium in the Royal Botanical 
Gardens, Seebpore, has been studying the growth 
of new plant? “ intentionally, accidentally, or 
naturally introduced ’’ in the Andaman Islands 
since 1866. A list of the Andaman flora in 1866 
recorded 520 indigenous species, and the number 
has since increased to 600, although four of the 
naturalised plants noted in 1866 have disappeared. 
A common Indian butterfly has made its appear- 
ance since the plant on which its larva feeds 
became naturalised. — Pioneer. 
Grant of L.and in the Eastern Lowcountey. 
— We hear that Messrs. W. Gow and Gordon 
Reeves have been applying for a grant of some 
thousands of acres of land in the lowcountry to 
the North-eastward of the Knuckles and Kalupahana 
range, near the junction of the Kalu and Amban 
gangas before they fall into the Mahaweliganga 
and we suppose not far off Polonnaruwa. Two 
young Surveyors are now busy blocking out in 
that neighbourhood. The soil is said to be very 
flne, the land flat with very heavy timber, though 
great parts have been chenaed. Rainfall is confined 
to the North-East monsoon and there is a great 
deal of wind in the South-West. Tea would therefore 
scarcely flourish there, and it has not transpired 
what products are likely to be cultivated — perhaps 
tobacco and cotton. Should a grant be made on 
lease, there will be conditions as to cultivation, 
as well as about reat. The outlet would probably 
be via the North road, 20 miles off. 
Detailed Estimates of Plantation Crops. 
— We have to thank planters in nearly every district 
in the island for the readiness with which they 
have responded to our request for approximate 
estimates of the outturn of tea, coffee, cocoa, cinchona, 
&o. during the current year. There are a few 
districts yet unrepresented in our bulky receipts, 
so that we must wait a week or two before 
beginning our analysis and compilation, to see how 
the results bear out the total estimates we have 
already put forward. We see our contemporary of 
the “ Times ” on the 5th instant arrived at the 
same figures for probable tea exports this year 
(namely 56,000,000 lb.) as we gave in our estimate 
on the 20th Jan., Mr. C. S. Armstrong indepen- 
dently sending us the same figures. We think it 
quite likely however, that Mr. Forbes Laurie’s 
figure of 68,000,000 lb. may prove nearer the actual 
lesult. 
