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Problems Of Yam Production In Our Community
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The family Dioscoreaceae comprises six genera but the genus Dioscorea is
the major one. About 600 species of Dioscorea have been identified,
among which 12 species are edible (Coursey,2006). Within this genus,
edible and marketable species are: Dioscorea rotundata (white yam or
Guinea yam), Dioscorea alata (greater yam or water yam), Dioscorea
esculenta (lesser yam or Asiatic yam), Dioscorea bulbifera (aerial yam
or potato yam) and Dioscorea cayenensis (yellow yam) which produces
edible tubers and bulbils (aerial tubers located in the axils of
leaves).
Some Dioscorea species, like floribunda and composite, are
appreciated due to their high tuber content of steroidal saponins, being
used in the manufacturing of oral contraceptives, sex hormones and
cortisone (Purseglove,2002; Applezweig,2007). The drug yams are still
essentially wild species (Coursey,2006). The English term “yam†is most
likely derived from the Portuguese word, ynhame, found in early
documents, itself being the transcription of niam, the word used in the
Malinke language spoken widely through the Guineas, Sierra Leone and
Ivory Coast (Coursey, 2006).
Yams means many things to most
people. To the farmers it is edible root tuber crop, which generate his
income for the up-keep of his family and himself. It has helped raised
the standard of living over the years. The oxford dictionary describe
yam as a starch tuberous root largely replacing potato as a staple food
in many tropical and sub-tropical countries of the world. Yam belongs to
the botanical genes discovered, but there are very many species of
great importance in West Africa.
The white yam (Discoreal rotonlata)
The water yam (Discoreal alata)
The yellow yam (discoreal caganesis)
Lesser yam (D. bulbfery)
Trifoliate or three leave yam (D. dumetorum)
STATEMENT OF THE PROBLEM
Falling yam productivity has fuelled calls for increased research
activities in yam – a crop that serves as staple food to millions of
people in Africa. There are great differences in yield between
individual countries (FAO, 2007), but for all countries, the average
yield level is far below the potential one, which has been estimated
(Gurnah,1974; Martin,1972) at 15-20 t for dry tubers ha-1 yr-1
(equivalent to 60-75 t ha-1 yr-1 on a fresh weight basis). One major
constraint highlighted for its contribution to declining yam
productivity is soil fertility degradation, due to nutrient depletion by
leaching, and erosion, and the loss of organic matter from most soils
in the savannah zone of Edo State. With increasing demographic pressure,
land use intensity and reduced forest cover, suitable land for yam
cultivation becomes gradually scarcer (Carsky et al., 2001). In Edo
State, farmers practice slash-and-burn agriculture for yam production,
which places great pressure on scarce virgin and fallow land resources.
Natural fallow, crop rotation with grain legumes, and mineral fertilizer
are the main soil fertility management strategies practiced here.
However, most farmers do not use fertilizers and manures to any
appreciable extent on yams.
The edible yams are root crop groom on a
field scale for the tubers.
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ABSRACT - [ Total Page(s): 1 ]Declining productivity of yam in Nigeria highlighted the need for a study to determine both the effect of fertilization on yam (Dioscorea spp.) yield andhe best agronomic management options available for stabilizing yam productivity, via the modeling of yam growth and development. This study addressed the above issues by carrying out a research which analyzed the problem of yam production in Nigeria. A questionnaire was administered to elicit information from respondents in the study area. The d ... Continue reading---
