.Tan. 1, 1903. 
THE TEOPICAl. AGRICULTURIST. 
445 
Clkaring. — This beiug admitted, it is obvious that 
ill planting Castilloa in open land it is necessary to 
plant at the same time trees to protect and partly 
shade it. As this adds very greatly to the cost of 
planting, it stands to reason that in selecting land 
for the cultivation of Castilloa, preference should be 
given to forest land. The larger trees are cut out — 
there are generally plenty of uses for them on the 
plantation — only the smaller trees being left standing 
between which the rubber trees are planted. 
Soil. — As regards the configuration of the land, 
and the best quality of the soil, some little discri- 
mination is also required. Regarding the soil, it 
may be said that Castilloa is very modest indeed, 
but, of course, this does not mean that just any soil 
is good enough. The best results are undoubtedly 
obiained on a deep, loamy, only moderately sandy 
soil. Whether Casiilloa should be planted on level 
or on hanging ground is a ratber more important 
question. In Mexico, I believe, rather large level 
tracts have been planted, but then the rainfall in 
Mexico is considerably less thaii what it is iu Colombia. 
It is quite certain that the trees re quire wtll-draiied 
l«nd, and this with a rainfall of 130 Inches, the 
figure for the Isthmus, means hanging laud. There 
are immense traces of unappropriated la' d of this des- 
cription north and south of the Isthmus. 
Climate. — The climate of Colombia more parti- 
cularly the districts north and south of the Isthmus, 
is a very great deal better than its reputation. 
I am inclined to think that the villainous climate 
of the stretch of land between Colon and Pjnamn, 
and the fiightful death-rate amongst the canal 
workers, has been taken to apply without distinction 
to the high-lyiig land adjoining the distric-. But 
it must not be forgotten that the susceptibility of 
the negro, at any rate those hailing from the West 
Indies, for zymotic diseases, is nothing short of 
extraordinary, the death rate amcnrst them even 
from measles being simply appalling. The white 
races under the same conditions enjoy comparative 
immunity. Moreover, the higher-lying districts 
adjoining the Isthmus are incomparably healthier. 
There is, therefore, no reason why in the next 
10 or 20 years rubber cultivation in Colombia should 
not attain to huge dimensions. Land is to be had 
piactically for the asking, the establishing of even a 
large rubber pUiila ion is ircredibly cheap, and 
the returns are large, certain, and permanent. 

AMERICAN SWEET POTATOES FOR 
INDIA, 
To THE EniTrn, ' Indian Gardening and Planting." 
Dear Sir,— I imported three American varieties 
of sweet potatoes last year, viz., Nansemond, New 
Jeraerj, and Virginia. These w?re first tried on 
the Bombay Farms. The first Bombay crop was 
propagated from imported tubers, the second crop 
was propagated in the usual way from, cuttings. 
It was planted on the 8th of April at.d was lifted 
at the end of July. A large number of cuttings 
were distributed from the first crop to various 
parts of India, therefore only about | acre was 
planted for the second crop. The aiea was too 
Bmall for very reliable outturn figure'. I give how- 
ever, the resitlta as under ; — 
lbs. 1 er acie. 
Nansemond ... ... 14.470 
NewJeisey ... ... 16,71-2 
Virginia ... ... 21,113 
The land was not directly ma lurj d, but was in 
good condition. The produce from the whole plot 
(21-80 acre) was sold lor E 'JO, or K 330 per acre. 
The crop also yielded a very large nr.mber of 
cuttings which have be< n used for distribution and 
for planting an ex: ended area i t the Bombay Farms. 
I havj now seen the lo v irieties growing on various 
descriptions of soil in tha Pai ja'i, Bengal, Central 
Provinces and Bombay. The plants everywhere show 
great vigour of growth. I believe the introduction 
of these varieties to be an undoubted success. It 
is important, therefore, to have these American 
varieties tried in ail districts where the crop ja 
important. Cuttings can be supplied during October 
for experimental trials if applications are made to 
my office at Nagpur. 
The crop does best on deep alluvial soil of a 
sandy or loamy character, but will also do well 
on any free working naturally dry soil of fair depth. 
The best crops are grown under irrigation iu the 
rabi season, but in districts where the cold of winter 
is severe and the total rainfall is not excessive, 
the crop will probably do best if planted in .June- 
July. 'The American varieties are not likely to 
thrive on deep black soil. 
The results reported from Poona show that the 
tubers were all sound and of good shape and size. 
They wero proved to cook well and have good 
flavour. The Virgina variety produced four or five 
tubers from each plant. These tubers were larger 
than those usually obtained from indigenous varieties 
The Nansemond and New Jersey vari rties produced, 
16 to 18 tubers from one plant. These tubers were 
smaller than tho^efrom ordiiiaiy indigenous varieties 
but v.'ere all of good marketable size. Tubers of 
each variety grew not far from the surface in 
clusters and were much easier to dig than those of 
ordinal y Indian varieties. 
The cultivator of sweet potatoes is put to no 
particular expense for seed. He simply uses as 
cuttintis the haulms of a previous crop. These 
cuttings may have to be planted in a nnrsery. A small 
nursery planted in March when the raid crop is har- 
vested will provide cuttings for planting a kharif 
crop in July, and this crop will, in its turn, provide 
cuttings for the next rahi crop, which should be 
planted in October-November. 
Full details regarding methods of cultivating this 
crop aie given in Vol. Ill of my Agricultural Te.xt- 
Book, but for easy reference I may refer to important 
points here. 
The soil shoula be of suitable class and be well 
worked by repeated ploughings and harrowing?. 
Beds should be formed if irrigation is required. 
The crop can be propagated from tubers, but more 
economically from cuttings or pieces of mature stem 
having four nodes to each cutting. The best 
cuttings are got from the middle portion of the stems. 
The diite of planting the main crop will depend 
upon the usual custom in any particular district. 
The main crop is sometimes planted in flat beds 
and sometimes in ridges made ab ut 18 inches apart. 
The Utter method is preferable- The cuttirgs if 
planted in ridges should be buried halfway between 
the base and the apex and on each side of each 
ridge, each cutting should he planted with two nodes 
buried and two ends above ground. A vigorous 
growth of long trailing stems is soon produced if 
the crop is healthy, and very little hand weeding 
is required. No irrigation is given in the rains, 
but if planted in the rahi season, irrigation is neces- 
sary every 8 to 15 days according to the character 
of the soil. 
The stems when in contact with wet soil after rain 
or irrigation become attached to the soil by rooting 
at the nodes. This must be prevented, otherwise 
small thin tubers of no marketable value form at 
each point of attachment. The tubers which form 
at the main root, moreover, will not grow so large 
as when the stems are kept quite free. The stems 
during growth must be repeatedly lifted dear from 
the ground and turned over to prevent the formation 
of these roots. These operations must bo done often 
if the crop is good and the foliage luxuriant, and 
always with care so that the stems and leaves are 
damaged as little as possible. 
In a luxuriant crop the growing points of the lorg 
trailing stems may be pruned cff without damaging 
