Rainfed rice - IRRI books - International Rice Research Institute

RAINFED RICE A SOURCEBOOK OF BEST PRACTICES AND STRATEGIES IN EASTERN INDIA
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Types of cultivars used
Traditional
Tall, weak-stemmed and awned cultivars with poor grain quality were
cultivated, as these were considered to have good tolerance to cold
temperatures at the seedling stage.
Though the yields might not be high, they helped subsistence farmers.
High-yielding varieties (HYVs)
Except in a few pockets, traditional cultivars are being replaced with
both early and mid-early HYVs.
The high-yielding varieties becoming popular are Gautam, Prabhat and
IR36, along with, of late, Joymati, Vishnu Prasad, Joyti, Prasad, Chinsura
hybrid -3 and some other irrigated varieties.
Yields are three to four times more than those of kharif rice.
Reasons for high yield of Boro rice
Better water management during crop growth
Bora rice responds to higher doses of fertiliser, resulting in higher
production
Less insect/pest infestation on the crop helps reduce damage
Higher solar radiation available to the crop
Lower night temperature during the early stages of crop growth in
winter facilitates the accumulation of photosynthates, thereby increasing
the carbon-nitrogen ratio
Favourable higher temperature at ripening period
The variation in these parameters explains variation in yield across the
region. With increasing Boro rice areas, both within and outside its
traditional boundaries, new cropping patterns have also emerged and are
adopted as per local conditions.
Boro -deepwater rice (DWR) system
Boro rice can be grown after harvest of kharif season DWR in the
stagnant water and residual moisture.
Various techniques are employed to adjust these two crops within a year
in a same piece of land:
•
selection of appropriate Boro varieties;
• early transplanting and harvest; and
• transplanting of aged DWR seedlings in the field.