By R. ROMANIS, D.Sc., Chemical Examiner, British Burmah.
The analyses of rice soils was undertaken at the instance of the Revenue
Settlement Survey, who wanted to know if the chemical composition of
the soil corresponded in any way to the valuation as fixed from other
evidence. It was found that the amount of phosphoric acid in the soil in
any one district corresponded pretty well with the Settlement Officers'
valuation, but on comparing two districts it was found that the district
which was poorer in phosphoric acid gave crops equal to the richer
one. On inquiry it was found that in the former the rice is grown in
nurseries and then planted out by hand, whereas in the latter, where the
holdings are much larger, the grain is sown broadcast. The practice of
planting out the young crops enables the cultivator to get a harvest 20
per cent. better than he would otherwise do, and hence the poorer land
equals the richer.
The deductions drawn from this investigation are, first, that, climate
and situation being equal, the value of soil depends on the phosphoric
acid in it; and, second, that the planting-out system is far superior to
the broadcast system of cultivation for rice.
Results of two analyses of soils from Syriam, near Rangoon, are
appended:
_Soluble in Hydrochloric Acid_.
I. II.
Virgin Soil.
Organic matter 4.590 8.5?8
Oxide of iron and alumina 8.939 7.179
Magnesia 0.469 0.677
Lime trace. 0.131
Potash 0.138 0.187
Soda 0.136 0.337
Phosphoric acid 0.100 0.108
Sulphuric acid 0.025 0.117
Silica ---- 0.005
-------- ---------
14.397 17.249
_Soluble in Sulphuric Acid_.
Alumina 17.460 15.684
Magnesia 0.459 0.446
Lime 0.286 trace.
Potash 0.616 1.250
Soda 0.317 0.285
--------- ---------
19.138 17.665
_Residue_.
Silica, soluble 11.675 \
69.546
" insoluble 49.477 /
Alumina 3.062 4.178
Lime 0.700 0.134
Magnesia 0.212 trace.
Potash 0.276 1.180
Soda 0.503 1.048
-------- ---------
100.000 100.000
These are alluvial soils from the Delta of the Irrawaddy.
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