Rainfed rice - IRRI books - International Rice Research Institute

Direct sowing vs transplanting: a comparison
Direct sowing
May be adopted easily under rainfed upland, deep
lowland and lowland dry situations.
Requires minimal water just sufficient for
moistening at the initial stage. (Newly germinated
seedlings will die within a few days if the soil
surface dries out or if they are inundated.)
Crop establishment involves less labour
(8-12 man-hours/ha)
More weed growth
Poor water control and more percolation losses.
In the absence of weed control, yield loss is
about 40-50% in direct seeding on dry soil and 20-
25% on puddled soil.
Root anchorage is poor and lodging is more
serious.
With proper weed management, gives moderate
yield even under upland low-rainfall situation.
Timely seeding may give a good yield with
proper weed and water management.
Land is used for a longer period, thus reducing
turnaround time.
Labour requirement and
energy inputs
Manual hand transplanting requires about
400-500 man-hours/ha, including nursery
raising and uprooting. This is about 47 and
39 times more than the labour required in
dry hand broadcasting and wetland hand
broadcasting, including seedbed
preparation.
Workloads per person are higher with
the wetland seeder (34.32 kilo joules/min)
and hand wetland broadcasting (15.30 kilo
joules/min) than in transplanting (12.97
kilo joules/min).
The human energy required in weeding is
much lower in transplanted rice (350 man-
hours/ha) than in hand-broadcast rice
(615 man-hours/ha in dry and 446 man-
hours/ha in wet).
Weeding in machine-transplanted rice
using weeders is still less (251 man-hours/
ha) than in other sowing methods.
Comparative Analysis of Direct Sowing and Transplanting
Transplanting
Suitable only under shallow and semi-lowland
situations.
Requires a good amount of water at the time of
transplanting but may resist short-duration drought
and moderate rain.
Is a labour-intensive operation (400-500 manhours/ha)
Less weed growth.
Better water control and reduced percolation
losses due to puddling of field.
In the absence of weed control, yield loss is
about 10-15%.
Root anchorage is better and lodging is not so
serious.
Cannot be used in a similar situation without
supplemental irrigation facility.
Delayed transplanting due to late rains and labour
shortage will result in drastic reduction in yield.
Land is used for a shorter period, thus
increasing turnaround time.
Effect on grain yield
A higher grain yield is possible in
transplanted rice than in broadcast rice
under the same rainfed lowland
situations with proper water
management techniques.
Prepared by:
M.R. Varma
Remember. . .
Under upland and deep
rainfed lowland situations,
with proper weed
management and timely
seeding, suitable varieties of
xoadcast rice give better
fields than transplanted rice,
wen under low-rainfall
conditions.
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