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At present, little information is available on the extent of any degradation that might
have already taken place in the rice-wheat systems. The quantification of sustainability
parameters is exceedingly difficult (e.g., measuremt?nt of regional trends in factors associ-
ated with declining soil fertility). Nonetheless, the possibility of soil and water degrada-
tion must be taken seriously for several reasons:
Lbngterm experiments on continuous rice-wheat croppillg have s11ofi.n that, over
time, yields of both crops decline at constant input levels.
Surveys reveal that farmers who ha\.e recently adopted thc rice-wheat pattern tend
to be enthusiastic about initial observed yield increases. However, farmers who
have a decade or more of experience with this system arc becoming concerned
about stagnant crop yields, even with higher rates of inputs.
TWO orni~ious signs are therefore emerging:
'I'he rates of productivity growth for rice ancl wheat are declining.
The quality of the soil and water dcvoteci to the rii-e.\vhe~t cropping systems niay
be declining (from over-mining of soil nutrients, decline of organic matter levels
increasing salinity, ctc.), coupled tvitl-I a builti-up of wr.zd, p.~thoj;cn, and pest
poyulatiol~s, all of which might be leading tcd stagnating yields.
These problems are exacerbated by r'ipid populaticn growth, loss of land to urbanization,
a slowing in the grov.?lh of fertilizer use, d\v:ndling availability of new agricultura! land
and water resources, increased dcn~and and cofiipctition foi water for non-agricultural
uses, and thc need to Increase product~on from 13ncl that IS already double- and even
triple-cropped. Urgent action is needed to ensure adequate future supplies of rice and
wheat.
It is also notcwortti)~ tl~~it the Tcchniiill Advisory Comniittcc ('TrZC) of the CGIAR recognized
the iniportancc of thc rice-wheat system artd rcconin-wnded in its 1993 I-'ri07;ties
and Str'jtegies paper (Chapter 13) that IRRI anil Cl?~lh.IYr work with national agricuitural
research systems (NARS) in the region on a rice-&fileat program as part of the CCIAR
ecoregional program for the warm arid and semi-arid tropics and subtropics for which
ICRISAT has been made the Convening Centcr. TAC has subsequently suggested that
IIMI and IFPRI be included in this ecoregional initiative. Many of the guiding principles
that TAC enut~ciated for the ecoregional approach to research are relevant to this initlative
and form a valuable framework for it.
In summary, problems associated with the rice-wheat system of Bangladesh, India,
Nepal, and Pakistan are appearing that threaten the sustai~~ability of this vital component
of the food security of these populous countries.
Research Methodology and Approach
One of the rnajor tasks of the collaborative initiative proposed in this document will be to
locate the specific areas most seriously threatened in these countries, identify the biolog-
ical, physical, and socioeconomic causes of the problems, and develop, test, and promote
the iniplementation of more sustainable, hgh productivity cropping systems.