Vergara - 1976 - Physiological and morphological adaptability of ri

GEOGR.~'\PH\’ AND CLIlylATE OF RICE 43
rice production, and yet a major portion of the rice crop in this area is produced
without microclimatic modification by man. The most serious limiting factor is
that much of the crop in this region is attempted without water control other
than ponding on the paddy of that rainfall which occurs naturally’. Problems in
this zone are legion and include insects, diseases. and cost of fuel, but the most
critical and least controlled is the variability over time of climatic parameters.
especially rainfall.
In the strict sense of the word these are not climate regions at all but are
regions portraying man's perception of the quality of the total environmental
syrstem for his use in rice production. In the core area man sees little use or need
to modify the climate in any wajv except in those few locations where a dryseasori
crop is desired. Hoivever. some major climatic modifications are absolutely
essential at the outer margins to produce a crop. Here man perceives the
opportunity to optimize the climatic conditions and thus to maximize his output.
Investments are heaygv", the expenditures of energy are great. and the retums
are high.
In the transitional areas man certainly perceives the climatic conditions as less
than optimum, but here man is willing to act as a satisfier rather than as an
optimizer. He is prone to gamble with nature. to invest as little as possible in
attempts to modify the climate, and to count on the blessings of the gods to
provide a good monsoon. to provide warm temperatures, to prevent serious
flooding, and to keep the typhoons auxay from the fann.
Clearly attitudes and conditions vary widely" within this broad belt. but in
general the rice farmers here have received less government assistance and less
effort from rice scientists than has any other group of rice farmers. In many
Way's these are the marginal areas for rice production and the farmers in such
areas are those leading the most marginal of existences. These are the farmers
described so well by Pearl Buck in The Good Earth and by Kamala Markandaya
in Nectar in a Sieve.
For a closer look at this problem let us focus attention on the Indian subcontinent.
In the northwest rainfall is so low and so variable from yjear to year
that rice is raised exclusively’ with inigation-area 3 on the world map of rice
climates. I11 the Ganges Delta. Assam. Bengal, eastern portions of Bihar, and
along the westem coastal lowlands, rainfall is sufficiently’ heavy and reliable to
provide only modest shifts in output. This is area 1 on the world map. However.
in the central portions of the region from Ultar Pradesh and western Bihar in
the north to Tamil Nadu in the south, the mean rainfall totals are marginal for
rice and the variability from year to year both in the timing of the onset of the
rains and in the total volume of precipitation is very great. A considerable
portion of the rice crop in this area is either unirrigated or watered from
unreliable sources such as tanks or shallow wells. This is area 2.
During the 20th century population in this latter portion of India has increased
by at least two and one-half times. as it has for India as a whole. The
resulting pressure on the land is enormous.