Rainfed rice - IRRI books - International Rice Research Institute

Influence of High-Quality
Seeds on Rainfed Upland
Rice Yield
W
est Bengal grows 0.6 million
ha of rice in rainfed
uplands. With the
introduction of improved-quality
seed, as in the mid-l970s, much
change in rice yield has been
noticed. To highlight the role of
improved-quality high-yielding
variety (HYV) seeds in enhancing
rice production in this ecosystem, a
project was carried out during 1992-
1995. The districts of Bankura,
Purulia, Birbhum and Midnapur
(West) were included in the study.
Characteristics of the environment
The bulk area is distributed in red and lateritic tracts.
The ricefieids are broadly divided into bunded and unbunded types of
topography ranging from 2% to 4% slope to flat, terraced or unterraced
land forms.
Because of the topography and high internal drainage arising from light
texture of the soil, the fields do not impound rainwater.
The rice crop in this region is generally directly sown in unbunded fields
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and transplanted in bunded fields.
The rainfall varies from 1200 mm to 1300 mm.
Monsoon generally starts from the second to third week of June and ends
by mid-September.
About 80% of the total rainfall occurs during these months. But due to
undulating topography and poor soil depth, 50% of the rain flows away
as runoff. As a consequence, the moisture balance of the soil normally
lasts for about 70-75 days, thereby extending rice cultivation in this
ecosystem.
Rice is sown just after the onset of monsoon.