Thanks for your questions.
>Dear Mr. Shannon,
>Like Ann Wells, I have little knowledge of sub-Saharan agriculture, social
>systems, or political situations so, I was pleased you posted her questions
>and responded to them.
>I am always concerned when single issue solutions are exported without a
>sense of the social system into which they will be introduced. From my base
>of not knowing, these questions spring to mind.
>How long is the land fallowed before it is economically feasible to crop it
This depends upon the ecological zone (rainfall, vegetation type), soil
characteristics and how the land was managed. Under shifting cultivation,
estimates in the literature vary but are in the range of 7-10 years for
savanna and about 16-25 years or more in forest. I believe the references I
cited in the previous post have something to say about that. These numbers
are based, I believe, on the time to return the field to its "natural"
vegetative state. I have not seen good data on the required fallow period
with modern inputs, but I anticipate that it would be reduced. Again, use
of an improved fallow with legumes would shorten this period, probably to
one or two years. With alley cropping, the question would be whether you
need a fallow at all. The first alley cropping trial Dr. B.T. Kang planted
in Nigeria in 1978 is in its 16'th year of cropping and as far as I know is
still sustaining yields.
>Do the herdsmen have some treaty or trading relationship with the farmers?
> Would it make some sort of sense to explore the possibility of the herdsmen
>doing a modified "rotational grazing system" -- ie moving their herds from
>one ag tribe's to another's as the pasture is used -- having the ag tribes
>plant and that pasture to grain/legume mix in rotation with food crops -- in
>partial exchange for meat and milk? The movement of the cattle herds this
>way would approximate the traditional nomadic lifestyle of the Massai et al
>and benefit the farmers by speeding up the process of regeneration.
In parts of Nigeria, the local crop farmers allow the Fulani to graze their
cattle on the crop residues left in the field after harvest at the start of
the dry season. This is believed by many to contribute to the fertility of
these soils. This mutual benefit of meat and milk for grazing occurs
between the Fulani and Hausa in Northern Nigeria. But in many areas,
especially where the tsetse fly is endemic (cattle are especially
susceptible to sleeping sickness), one doen't find people dependent upon
cattle. The traditional nomadic herding is probably doomed, anyway, by
modernization, or at least will be greatly restricted as more congested
highways criss-cross the country and towns develop. I am sure that cattle
rearing will survive in some form, but I cannot predict how that will be.
In Kenya, settlers are moving into areas the Massai consider their
traditional grazing lands and they are having the same conflicts the Western
U.S. did between cattlemen and crop farmers. On the other-hand there is
much more cattle raising by crop farmers in Kenya than one sees in West
Africa, and there is also ox traction, so there is probably more scope for
the types of solutions that you are suggesting (improved pastures, etc.).
>Also, don't local flora growing naturally in those soils fix or mine
>nutrients unavailable to our "exotic" food crop species? Would it make some
>sense to use these "weed" species as a local cover crop to help correct some
That is essentially what the natural fallow is. What researchers are
working on now is how to speed it along. ICRAF(International Centre for
Agroforestry Research) is doing some work along that line in the forest area
>I am glad to hear the regeneration ag research on leguminous tree species
>pioneered by the Rodale gang is being tried.
>Thanks for correcting my ignorance,
Dennis A. Shannon
Department of Agronomy and Soils
202 Funchess Hall
Auburn University, Alabama 36849-5412