Is it Possible to Find a Third Way

 Between "Green Revolution"

and Traditional Systems of Agriculture?

 C. M. Messiaen
 INRA Domaine Duclos
 97170 Petit-Bourg, Guadeloupe


 Traditional systems of agriculture still feed millions of peo-
ple in tropical countries. There is probably a superior limit to
their yield potentials, especially in over-populated situations.
However, many things can be learned about the biological


mechanisms which explain their productivity, and perhaps it is
possible to imagine ameliorated systems in which productivity
would be ameliorated by minimal inputs of chemical aid, and
adequate plant breeding.


 "Biological agriculture," as it is known to Europeans, or
"organic farming," seems to be a new, although less and less
marginal orientation for industrial countries. On the contrary,
millions of small farmers in tropical areas are still working in a
"biological" way, without chemical fertilizers or pesticides. These
traditional methods still dominate food production in Haiti,
where they have been thoroughly investigated by the "Madian-
Salagnac" team, founded by MMrs Brochet, Cavalier and De
Reynal (French technical cooperation). In French West Indies,
such methods were used 30 years ago to produce food crops: root
and tubers, plantains, pulses and various vegetables. Some old
farmers still work in this way; younger ones use chemical fer-
tilizers, pesticides and weed killers on industrial crops (sugarcane,
bananas).
 Ten or 20 years ago we were all sure that a "green revolution,"
using high yielding cultivars and fertilizers, would be successful
everywhere for food crops and for industrial crops. French
agronomists worked with the same orientation, even though they
spoke less of the "green revolution."
 We now wonder, as energy and nitrogen become more and
more expensive, if we will be able to apply the "green revolution"
to the whole tropical world. Would it not be better to understand
the biological mechanisms by which soil fertility was preserved
and epiphtotics restricted in traditional systems, and to try to
ameliorate and stimulate them, rather than sweep them away by
application of large amounts of fertilizers and pesticides? On the
contrary, would it be wise to decline the use of any chemical help,
being unconscientious of the productivity limits of exclusively
biological systems, especially in overpopulated countries?



Yield Limitations of Traditional Systems
 First, let us observe that these systems may operate in two dif-
ferent ways:
 1. Partial cultivation of the arable land allows crop produc-
 tion and soil fertility restoration by nitrogen fixation,
 organic matter accumulation, and subsoil mineral absorp-
 tion by deep roots to occur on different plots.Restorer plots
 either are in rotation with cultivated plots (shifting cultiva-
 tion), or, vegetable or animal wastes are transferred from
 them to cultivated plots. European "biological agriculture"
 systems work in this way, since they use large amounts of
 composts or algae taken from outside.

 VOL. XX-PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY


 2. Total cultivation of the arable land occurs when population
 density becomes so high that there are no more fallows.
 Cultivated plants alone, with their associated microflora,
 must assume the two functions: food production, and soil
 fertility preservation.
 We shall try to choose some more or less typical examples of
this situation:
 a. The traditional "Bulu" rice grown in Java (Oryza sativa var.
 javanica), is associated with an aquatic nitrogen-fixing
 microflora (blue-green algae, Beijerinckia etc...), which
 yields 3.6t/ha with two crops/yr and permanent rains.
 b. The associated culture of maize, sorghum and pigeon pea
 in the south peninsula of Haiti, gives 2.3t/ha of cereals +
 peas for nine months when rains arrive in the good season.
 Here we can attribute nitrogen fixation to the Cajanus
 tree, which produces It leaflets and 0.3t peas/ha although
 the intervention of Azospirillum assicated with maize and
 sorghum roots might not be excluded (Fig. 1).
 c. Vegetable and tuber gardens in volcanic Guadeloupe,
 associate yams, tannia with shorter-cycle crops like beans or
 cucumbers, with pigeon pea borders. First estimations of
 yields from these gardens indicate 8t tubers/yr + 2 or 3t
 vegetables, and approximately 2.5t dry matter (Fig. 2).
 d. Wheat fields in Europe before fertilizer use, or today in the
 plots without fertilizer at the Grignon Agriculture School
 in France yielded 1.2t/ha for an 8-month cycle.

FIG. 1: Associated culture of maize, pigeon pea and sorghym in Haitian lowlands,
as seen in July.


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