1 Sept., 1899.] QUEENSLAND AGRICULTURAL JOURNAT. 295 
Tropical Industries. 
MANURING OF TROPICAL PLANTS—COTTON, 
The cotton plant requires, in the first place, a deep, permeable soil, preferably 
a sandy loam. The tap root of this plant often descends more than 3 feet into 
the ground, and, during the four and a-half to five and a-half months of 
vegetation, it 1s compelled to draw its supply of moisture from the deep 
of the soil. Heavy clay and sour humus soils are not suitable for th 
cultivation of this plant, and shade should be avoided 
requires light. Arrangements should be made for ar 
localities where the amount of rain that falls betwe 
vegetation and harvest time is an uncertain factor. 
er layers 
e proper 
, as the cotton plant 
tificial irrigation in all 
en the beginning of the 
Investigations in America have established the 
amounts of various substances removed from 1 
#300 lb. of fibre and 654 Ib. of seed :— 
Ib. 
following figures for the 
acre by an average crop of 
Ib. 
Nitrogen... ... 20°80 Lime an a 1-68 
Phosphoric acid... 6°84 Magnesia... Hn BHEY/ 
Potash xx, ox HSH Sulphuric acid ai; Weil) 
Soda nee oe (OO) Insoluble... on, BEB) 
Dr. Wohltmann* cives the followin 
5 
1 g figures for the average analysis of 
American Sea-Island Cotton :— 
STEMS. LEAVES. FIBRES. SEED. 
Per cent. Per cent. Per cent. Per cent, 
Pure Ash ... ee 345 1:81 7:9 1:12 38 
containing — 
Lime ... tk ty .. 348 3845 204. 47 
Macnesia od on BRE 13 4-0 18:2 
Phosphoric acid wi wo er 18°7 155 29:0 
Potash ohn ms eet leh! 15°5 29:2 33°8 
Soda ... aes og Pemel ois 8°9 13°5 9:9 
Oxide of iron WH rt eds} 3:2 ? ? 
Chlorine is ms ar eal 6:9 6:2 V1 
Sulphuric acid a4 dp PB} 56 6:3 12 
Silicie acid... i tee AGL 67 4-0 03 
The application of nitrogen to cotton is absolutely 
of the short growing season of this plant. The 
stems and leaves is, as rule, returned to the soil 
However, if the stems and leaves, instead of being 
on the fields—a custom that is still prev 
contained in them will be lost. 
indispensable, on account 
plant-food contained in the 
by ploughing them under. 
ploughed under, are burned 
alent in many sections—the nitrogen 
The fibres and seed are removed from the field, and used in industrial 
manufactures ; the plant-food ingredients contained in the fibres and seed will, 
therefore, be lost, if the residue obtained in preparing oil from the seed—virz., 
* Dr. Wohltmann, die natiirlichen Factoren der tropischen Kultur, 1892, 
