The gap in yields between irrigated and non-irrigated areas has widened, and is
expected to widen further. Yields of rice grown in the Northern, temperate zones are
almost double those grown between the Equator and the Tropic of Cancer. This is
mainly due to better management, increased use of fertiliser, more reliance on
irrigation and less on rainfall, and the use of japonica types, which have a higher
yield potential than the indica types normally grown in the tropics.
UTILISATION
About half of the rice grown is consumed on the farms where it is grown. Apart
from human consumption rice has few other uses. The husks left after
pounding the “paddy” (this word applies both to the unhusked grain and to the
growing crop) is not suitable as animal food nor as fertiliser; this bran is used in
bedding, litter, fuel and building materials such as hardboard.
The rice bran (or rice meal) left after pearling and polishing is a valuable
source of animal and poultry food. Milling of rice greatly reduces its human
food value.
The straw can be fed to animals but it is inferior to other cereal straws. It is also
used for strawboards, for thatching and brading, and for making hats, packing
material, broom straws and mats. In Thailand and China the straw is used for
the culture of mushrooms.
So-called “rice” paper is made from the pith of the rice-paper tree (Tetrapanax
papyriferum), a member of the Araliaceae or ginseng family, not from rice.
LIMITATIONS
Rice can be a very labour intensive crop to grow. In some primitive systems
more than 800 man-hours per hectare are needed to produce a crop.
Monocropping is often inevitable as there may be few or no other crops suitable
for growing in the paddies. This tends to lead to a build up of diseases, insects
and weeds.
Many varieties of rice, including hybrids and especially photosensitive indica
types, are adapted to grow well only in small, limited regions. They
sometimes also need to be planted within a specific and rather short period of
time, and to be heavily fertilised, in order to produce an economic yield.
The protein content of the grain of 6–8% is rather modest.
1, or aneurin), other
B vitamins and minerals.
(*)Beriberi—also known as Athiaminosis and Kakke Disease.
beriberi).
• • • • • • • • •
A disease of the nerves of the arms and legs, commonly found in eastern and
southern Asia. Symptoms include fatigue, diarrhoea, appetite and weight loss, dis-
turbed nerve function (dry beriberi, or endemic neuritis) causing paralysis and
wasting of limbs, water retention, swelling of body (edema) and heart failure (wet
132 TONY WINCH
The name comes from the Sinhalese language, “I cannot, I cannot”.
When a high proportion of the diet is white rice, there may be a risk of beriberi(*),
a disease arising from a deficiency of thiamin (Vitamin B
