occurs in the drier landward part of the Niger Delta where crop farming
assumes considerable importance. In contrast, the seaward part of the delta
which is inhabited by
the Izons and the Itsekiris,
is more swampy and is characterized by extensive creeks, on account of
which fishing replaces farming as the dominant aspect of the rural economy.
As with most parts of
The main agricultural systems include shifting cultivation ( also known as rotational bush fallow), permanent cultivation and livestock production; the last mentioned being relatively unimportant, although a viable means of animal protein supplementation in an area where crop farming is the dominant feature of agriculture.
cultivation, also known as the rotational bush fallow, is characterized
by impermanence of cultivation on the same site, with short periods of cropping
alternating with longer periods of fallow during which the site is left
uncultivated. A distinct feature of this system of farming is the rotation
of fields. A farmer usually owns several plots or fields which he cultivates
sequentially on a rotational basis. He cultivates a plot for a few years,
usually about 1-3 years, and then abandons it temporarily when soil fertility
declines. During cropping, soil fertility declines rapidly and since fertilizers
are not applied to sustain yields, the farmer is forced to abandon the cultivated
site after a few years and the land is allowed to regenerate fallow vegetation.
The vegetation that colonises an abandoned farm at the cessation
of cropping is called fallow vegetation.
It helps to restore soil fertility which declined during cropping. In some
cases, farmers are forced to abandon
a cultivated site after a few years because of the problems
of pests, crop diseases or because of the difficulties of coping with the rapidity of weed growth after a few years of cultivation.
In the past when land was still plentiful, a cleared site was usually cultivated
for 1-3 years before being fallowed for a period of 3-10 years. Rapid population
growth and the problem of land shortage have drastically reduced the amount
of arable land in Urhoboland and farmers have reduced fallow periods considerably
to 1-3 years and in some cases, continuous cultivation has emerged. It is important to point out right from
the outset that shifting cultivation is not unique to Urhoboland, rather
it is a pantropical system of agriculture that
is widely practised in the humid and sub-humid
tropics including large areas in
the cultivated site is left to fallow after a few years of cultivation,
the site is quickly colonized by herbaceous plants such as Tridax procumbens, Euphorbia hirta, Panicum maximum and forbs, especially Chromolaena odorata.
These weeds invade the farmland before cassava is harvested. These herbaceous
weeds and forbs are replaced by woody plants such as Sterculia tragacantha,
Anthonotha macrophylla, Harungana
madagascariensis , Ficus exasperata and Rauvolfia vomitoria
after about 5-7 years. Harungana madagascariensis is now becoming
rare in fallow vegetation in Urhoboland presumably due to soil fertility
decline, consequent on shortening of the fallow period, and frequent cultivation.
These woody plants help to replenish soil organic matter and nutrient status
by protecting the soil against soil erosion, enhancing humus and nutrient
accretion in the soil through litterfall and
mineralization and by recycling nutrients leached into the subsoil back to
the topsoil. The process of vegetation development and soil fertility restoration
in rain forest fallows in south western
system of shifting cultivation has undergone intensification during the
past two or three decades, mainly in response to acute land shortage. The
problem of land shortage has been further exacerbated by the widespread
growing of a perennial
tree crop, rubber, particularly
since the 1950s. Intensification of shifting cultivation in Urhoboland merely
involved the reduction or elimination of the fallow period without resorting
to the use of fertilizers or integration
of soil fertility enhancing trees such as Senna siamea
or other legumes into farms. In areas around large towns such as Ughelli and Warri, continuous cultivation without
using fertilizers is emerging. Even in the more fertile soils of south western Nigeria derived from basement complex
rocks, Aweto et al (1992)
observed that continuous cultivation of cassava intercropped with
maize led to soil nutrient and organic matter decline. In the less fertile
soils derived from sedimentary rocks in Urhoboland, continuous cultivation
without fertilizer application is likely to have a more drastic effect on soil nutrient status
in view of the fact the soils naturally have very low weatherable mineral reserves. It is very probable
that continuous cultivation has resulted in declining yields which may have
stabilized at very low levels. As pointed out earlier, the widespread shift
from the cultivation of yams to a less demanding crop- cassava- is largely
in response to the elimination or shortening of the fallow period and the
attendant decline in soil fertility. In view of the high cost of imported
fertilizers and the adverse environmental effects such as eutrophication that would result from the application
of chemical fertilizers, the adoption of agroforestry
appears to hold greater promise for the intensification of shifting cultivation
Agroforestry is the practice of integrating trees into
farmland in order to help maintain soil fertility and possibly help to raise
the level of agricultural productivity. Trees help to maintain soil fertility
by adding litter to the soil, improving soil physical status while their
roots absorb nutrients from the subsoil and from the weathering zone of rocks
below the ground and subsequently recycle such nutrients to the topsoil (
Young 1997). Presently, the only tree that Urhobo farmers selectively protect
and integrate into their farms is the oil palm ( Elaeis guineensis) which is the main source of vegetable
oil in the forest zone of West Africa. The oil palm is selectively retained
on the farm because of its economic importance, a practice which has led
to the emergence of oil palm groves.
Oil palms also feature prominently in cultivated plots of cassava, maize,
cocoyam and other field crops. Although, the retention of oil palms in cultivated
arable land in Urhoboland is agroforestry, the
beneficial value of the tree is largely restricted to protecting the soil
against erosion. Aweto & Ekiugbo (1994) have observed that oil palms tend to
deplete soil nutrients due to long term nutrient immobilization in the trees
and the harvesting of palm fruits which constitute a drain on soil nutrient
capital. In addition
to the palm, it would be necessary to integrate other tree species especially
those that improve soil fertility into farmlands in order to enhance sustainability
in the long run. The tree, Albizia adianthifolia, has been reported
by Prinz (1986) to improve soil organic matter,
exchangeable calcium, magnesium, cation exchange
capacity and available phosphorus of soil under its canopy in
Permanent cultivation is used in this context to refer to the antithesis of shifting or discontinuous cultivation. Permanent cultivation in Urhoboland involves the continuous cropping of little patches of land around or near houses in rural areas and the cultivation of perennial tree crops such as para rubber (Hevea brasiliensis) and the oil palm (Elaeis guineensis). The cultivated patches adjoining houses in rural areas are fertilized regularly using household refuse, including ash, yam and cassava peels and food remnants. They are very small, rarely exceeding 0.1 hectare and should be more be more appropriately referred to as home gardens.
with shifting cultivation, the practice of cultivating patches of land
near dwellings is not unique to Urhoboland. Home
gardens have been reported for other parts of the tropics, especially
tree crops such as guava, citrus and mango are grown in Urhoboland, they are insignificant compared to oil palm and rubber which are the dominant tree
crops. The oil palm is one of the most important
indigenous trees in the forest zone of West Africa. In Urhoboland, the
palm is a source of vegetable oil, the fibres
and hard shells of the fruits are used as fuel for cooking and heating,
and the fronds for making brooms and baskets. The tree is also tapped for
wine. Several decades ago, palm oil was the main fuel used for lighting
homes prior to the importation of petroleum products. In the past, oil palms
were not planted by farmers. The palms grew and still grow wild in farmlands,
bush fallow vegetation and in clearings. It is rare for the oil palm to
grow in dense primary forests (
most widely grown tree crop in Urhoboland is an exotic, para rubber
(Hevea brasiliensis) . There
are a number of indigenous rubber-producing trees in
Rubber trees deplete soil nutrients over time as a result of nutrient uptake and storage in the trees and due to nutrient loss from the trees via the latex collected ( Aweto 1987a). In most parts of Urhoboland, rubber trees have become old and latex yield has declined considerably, mainly on account of old age of trees, declining soil fertility and bad tapping techniques. Since rubber provides rural employment and helps in some measure to stem rural-urban migration, it would be necessary to rehabilitate old and unproductive rubber plots.
number of indigenous fruit trees such as Irvingia gabonensis,
Chrysophyllum albidum and Maesobotrya
barteri are not cultivated and are gradually
becoming extinct. Irvingia
fruits are in great demand, especially the dried seeds locally known as
“ogbono” that the Igbo people relish. The sustained
supply of the fruits of Irvingia gabonensis and other forest fruits
is uncertain as most forest trees have been destroyed as a result of widespread
deforestation in Urhoboland. Valuable fruit trees such as Irvingia should be grown in farmlands
and possibly in plantations
for more effective management and in order to ensure supply of such fruits
in commercial quantities. Fruits can be commercially processed for juice
or canned and this could provide the basis for the establishment of agro-based
industries that process indigenous fruits of the rain forest zone. The fruits of Maesobtrya barteri can be used to produce fruit drink that
is similar to black currant drink now imported into the country. The establishment
of plantations of these fruit trees and of the allied agro-based industries
will, hopefully, provide employment for Urhobo youths and help to stem
the tide of brigandage and youth
restiveness in the northern part of the
Given the natural rain forest vegetation, livestock production is relatively unimportant compared to crop farming. A few poultry are usually kept in rural areas as sources of meat. The keeping of poultry for the production of eggs is unimportant in rural areas. However, in the outskirts of large towns such as Warri, Ughelli and Sapele, commercial poultry production assumes considerable significance and poultry are reared for the production of both meat and eggs to meet the requirements of urban dwellers with higher levels of income. Local unimproved varieties of poultry are reared in rural areas under the free range system. Chicken scavenge for food, feeding on insects, food remnants thrown into dump sites behind houses and plant materials. Local chicken produce very little meat compared to those reared in commercial poultry farms.
few goats and sheep and occasionally pigs are also kept by Urhobo people in villages as a sideline
to crop farming. They are usually allowed to roam about in villages, scavenging
for food, and they often damage crops in cultivated plots near settlements.
Occasionally, goats and sheep are kept in enclosures and fed with peels
of cassava, plantains and yams, supplemented with grass and browse supplied
by the farmer. There is very little or no integration of livestock and crop
farming in Urhoboland, unlike in the drier savanna of northern
IMPACT OF AGRICULTURE ON THE ENVIRONMENT
Perhaps, the most widespread and striking impact of agriculture in Urhoboland is the pervasive replacement of the natural, floristically diverse rain forest ecosystem with monocultures of rubber farms and other agricultural ecosystems of field crops such as cassava, maize and yams intercropped. The agroecosystems that replace the natural rainforest are less diverse floristically and are much less complex structurally than the original rain forest. Although, rubber “plantations” which constitute the most widespread agricultural land use in Urhoboland, appear superficially similar to a forest, they are less efficient than the native rain forest in terms of nutrient cycling and soil conservation. As pointed out earlier, rubber trees tend to deplete soil nutrients over time. As with other exotic single-species tree plantations in the rain forest zone of West Africa, the establishment of rubber plots destabilizes the efficient cycling of nutrients in the natural rain forest ecosystem. This is mainly because single –species tree plantations usually immobilize soil nutrients faster and return less nutrient to the soil through litterfall and mineralization and rainwash than the natural rain forest (Aweto, 2001). Widespread conversion of rain forest into single-species tree plantations is ecologically unsound as the long term sustainability of such tree monocultures cannot be guaranteed, except, perhaps, with generous application of fertilizers. The conversion of rain forest into monocultures of indigenous oil palms also, have a similar effect of destabilizing the “closed” or “tight” nutrient cycle of the natural rain forest.
A major problem associated with agriculture as pointed out above is the loss of biodiversity . Burning the dried slash of cleared vegetation to release nutrients into the soil, is an important aspect of soil fertility management during cropping, especially under the system of shifting cultivation. As a result of frequent burning associated with cultivation, farmlands lack many woody species. Trees such as Harungana madagascariensis, Antiaris toxicaria, Milicia (Chlorophora) excelsa, Pentaclethra macrophylla which were common in Urhoboland three or more decades ago, are becoming rare. These and other tree species do not regenerate fast, as they used to do. This is mainly because of the non-availability of seed-bearing parent plants due to widespread deforestation and conversion of rain forest into plantations or farmland. Deforestation in Urhoboland has not only caused loss of plant species but also of wildlife. Destruction of forests results in loss of habitats and sources of food for many wildlife species. Wildlife such as elephant (Loxodonta africana), lion (Panthera leo) chimpanzee (Pan troglodytes), leopard (Panthera pardus) and hippopotamus (Hippopotamus amphibious) have become extinct in Urhoboland.
problem of soil fertility impoverishment as a result of shortening of the
fallow period or conversion of rain forest into plantations of rubber or
oil palm has been referred to. Erosion, which is mainly responsible for
silting up of rivers such as the
CONSTRAINTS ON AGRICULTURE
The institutional and socio-economic constraints on agriculture in the developing countries are well known and will not be considered here. This section, therefore, concentrates primarily on environmental constraints which hinder agricultural production in Urhoboland. A major constraint on agriculture in Urhoboland is the soil which is inherently of low fertility. As pointed out earlier, the soils are predominantly sandy, with sand accounting for up to 90% of the mineral fragments in the topsoil. On account of their sandy nature the soils have a very low nutrient holding capacity , as evident in their low cation exchange capacity which may be as low as 4 cmol/kg of soil or lower. The organic matter content of the soils is also low, even under rain forest vegetation. This, again, reflects the sandy nature of the soils and the heavy rainfall which leaches humus and nutrients from the soil. The soils are also acidic, mainly due to the pronounced leaching associated with heavy rainfall experienced in Urhoboland. The pH of the soil may be as low as 4.5 or lower in the topsoil. The implication of the pronounced acidity of the soils is low base saturation which will further exacerbate the problem of low nutrient availability resulting from low cation exchange capacity.
problem associated with agriculture is frequent flooding. The ground water
table is high, rising to or near the ground surface during the wet season.
This usually leads to flooding, especially after a spell of intense and
heavy downpours. Crops such as cassava and guinea yam have to be harvested
before maturation as a result of flooding. The grassland patches of Urhoboland
contain grasses such as Panicum maximum, Hyparrhenia sp.and
the legume, Centrosema pubescens, which are suitable
for feeding livestock. Aweto (1987b) suggested
that ranches of sheep,
goats and humpless cattle that are indigenous
to the rain forest zone should be established in the savanna patches to utilize
their grazing resources. Flooding during the
wet season appears to be a major constraint hindering the utilization of
the savanna vegetation of Urhoboland for grazing. Presently, the savanna
areas are used for
grazing cattle from the drier savanna lands of northern
Although, Urhoboland is suitable for growing tree crops on account of the long growing season and heavy rainfall combined with deeply weathered soils, the soils are prone to nutrient depletion, especially when used for growing tree crops which make long term demands on soil nutrients. The problem of nutrient depletion appears to have been worsened by the fact that the soils are deeply and intensely weathered. Consequently, they lack adequate weatherable mineral reserves to replenish nutrients taken up by crops and subsequently lost from the ecosystem via harvested crops or other products such as latex in the case of rubber. Mainly on account of their low weatherable mineral reserves, the soils are plagued by the problem of declining yields when used for intensified production of field crops with reduced or no fallows and little or no fertilizer application. The application of substantial quantities of fertilizers by the farmers in the near future appears unlikely in view of the high cost of imported fertilizers and the inability of most farmers to obtain locally produced fertilizers. The point needs be made here that, in view of the low cation exchange capacity of the soils, substantial quantities of applied fertilizers will be leached from the soil and become unavailable for cultivated crops.
Rural-urban migration, accentuated by the acquisition of western education and values by Urhobo youths, has resulted in shortage of farm labour and declining farm productivity. In several cases, oil spills and related disasters have resulted in loss of farmland and forced migration of people to towns such as Warri, Sapele and Ughelli to further aggravate socio-economic problems in these towns. Another related problem is that of gas flaring which has also robbed the people of valuable farmland. Around each gas flare site is an island of scorched and unproductive land - the product of excessive evapotranspiration and thermal decomposition of soil organic matter due to excessively high temperatures in the immediate vicinity of the gas flare site.
This paper advocates the development of traditional agriculture through agroforestry which will not only help to maintain and possibly improve soil fertility to ensure sustainability of traditional agriculture but would also help to provide fuelwood to rural farmers. Decline in soil fertility in Urhoboland is partly due to neglect of the cultivation of leguminous crops, especially cowpea and groundnuts. Both crops are good cover crops and also serve as green manure. In addition to reducing soil erosion, they help to replenish soil nitrogen (Irvine, 1969; Onwueme & Sinha 1991). The reintegration of cowpea into farmlands and the intercropping of groundnuts with maize will help to improve soil nitrogen levels. This measure together with the practice of agroforestry will help to improve soil nutrient levels ( in spite of the intensification of agriculture) and help to reduce probable future reliance on inorganic fertilizers which may have undesirable effects such as pollution of surface and underground water resources.
It will be necessary ,also, to develop plantations of indigenous trees such as Irvingia gabonensis, Chrysophyllum albidum, Maesobotyra barteri and Spondias mombin which can hopefully serve as the basis for local raw material based industries such as fruit canning and the manufacture of fruit drinks and jam. In order to ensure the long term sustainability of such plantations, it would be necessary to establish the plantation tree species between strips or stands of other forest trees in order to enhance biodiversity and make nutrient cycling more efficient. The establishment of cassava-processing and starch manufacturing factories could further enhance the development of arable agriculture and possibly the export of cassava products, if the policy of cassava development is vigorously pursued at the national level.
the problem of youth restiveness in the
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