Rice-Wheat Cropping Systems of the Indo-Gangetic Plain of India

flexibility in planting time has induced
farmers to advance the transplanting
schedules of rice to still earlier dates so as
to enable them to practice double cropping
according to convenience of management of
the rice-wheat cropping system (RWCS)
within the overall limitation of their specific
agro-ecoregional domains.
The basic agronomic technology
applied to RWCS is very similar throughout
the IGP. It has led to a rapid increase in
the cultivation of RWCS since the
introduction of HYVs of rice, in the 1970s.
The area under rice has been extended to
even lighter textured soils, where the crop
is being grown virtually without any
ponding of water; just by keeping the soil
wet enough to prevent development of more
than hair-size cracks. In these areas, no
ponding of water in paddy is done except
for the initial two weeks or so. This
ponding is practiced for effective weed-kill,
from the applied herbicides–primarily
‘butachlor and arozin’ groups of herbicides.
Here also, percolation rates being very high
(more than 2 mm/hour) the deep
percolation losses of water soon after the
transplanting of rice are high. Therefore,
paddy fields are watered daily, by keeping
tubewells running almost non-stop,
supplemented by canal waters at frequent
intervals (because the canal water is
available on a weekly rotational basis); and
in these areas irrigated rice is being grown
with a water use of about 150 cm. Most of
the deep percolated water is in fact being
recycled. In spite of the extensive recycling,
the water-table of the system is receding.
The evaporation losses are high, both from
paddy fields and conveyance channels, and,
therefore, the water-table is showing a sharp
decline in fresh water areas; rise of watertable
is, however, observed in the zones
where underground waters are saline/
alkaline.
2
The general yield realized for rice
(unhusked paddy) in the north-western IGP
has been very high (5–10 t/ha), at least 2
to 3 times greater than that harvested
earlier from the traditional paddy-growing
areas. This has been ascribed to
comparatively long, uninterrupted sunshine
hours experienced in this region (13–14
hours) and comparative freedom of these
two crops from major insect-pests and
diseases due to relatively weed-free and
hygienic conditions practiced by the farmers
of this region. The extent of herbicide use
covers almost 90–95% of rice area and up
to 60% of wheat area in Punjab state of
India. The irrigated culture, supported by
mechanized farming practices and large
consolidated holdings, has allowed
development of sophisticated agronomy of
rice-wheat cropping systems; and relatively
high levels of productivity. The extent to
which such high levels can be sustained in
the future is a question of utmost concern.
The committed procurement policy
particularly of the Government of India
(GoI) to purchase these cereals at
remunerative support prices has further
encouraged the farmers to plough-back the
profits accruing from higher yields into land
and development, and refining of the field
environment to conform to HYVs ricegrowing
requirements. The farmers, on
their own initiatives and without any
significant guidance from the Government,
State Agricultural Universities (SAUs) or
other National Agricultural Research
Systems (NARS), have undertaken largescale
land-leveling works, including
removing the surface sandy/coarse soil
material to make the soil amenable to ricegrowing.
As a result, there is now little left
of the former areas of extensive sand dunes
or unleveled fields in rice-growing areas of
the IGP states of Punjab, Haryana or
Western Uttar Pradesh which together
account for much of the rice-wheat area in
the country, out of a total rice-wheat area
of about 10.5 m ha (Tandon 1994).