River basin management and food crisis in Nigeria

River Basin Development is one of the key agricultural programmes embarked upon by Nigeria to meet the challenges of escalating import bills on food. This paper takes a critical look at the various efforts made by the management of the River Basin Authorities in responding to the current food crisis. The rationale for the huge financial allocation made to the Authorities is questioned, and the management lapses in their key areas of operation, such as irrigation, mechanization and extension services, are discussed. It is found that despite the huge financial investments made in the river basins, their impact is hardly felt, not only in terms of food production capacity but also in the production performance of the peasant farmers. The paper argues that the problem of food crisis in Nigeria could be solved by strengthening the ability of the peasant farmers and farmers co-operatives through financial aid and extension services, and not by huge financial investments on high technology agricultural projects, characterized by centralized administration and expatriáte management.     

Preliminary assessment of trace metals and polycyclic aromatic hydrocarbons in the sediments

Total concentrations of Cd, Cr, Co, Fe, Pb, Ni, Mn and Zn were determined by atomic absorption spectrophotometry in the surface sediments of Taylor Creek, Southern Nigeria. The most concentrated trace metals, ranging from 113.2 to 5160.7 mg/g-dry weights were Fe, Pb, Mn, Ni and Zn. There was no significant variation in sediment-associated metal levels (P>0.05). The metal pollution index was highest at Agbia/Nedugo and is attributed to local contamination of the Creek. The concentrations of low molecular weight polycyclic aromatic hydrocarbons (PAHs) were also detected and quantified in the sediments by capillary gas chromatography equipped with a flame ionization detector. The concentration levels of 178.1-1266.3 mg/g-wet weights were high for the PAHs. The results indicate that the pollutants, which are bio-accumulatable, could contribute to inferior biodiversity, and shifts in community composition from sensitive to tolerant taxa.     

Expanding a network of public facilities with some fixed supply points

Conclusions In general terms, this paper has demonstrated how the expansion of public facilities can be phased and implemented within the framework of certain policy objectives. Given an existing network of hospitals, for instance, it is possible to plan and implement the provision of additional facilities in a manner that enhances the spatial efficiency of the expanded network. The expansion can be executed in such a way that with the addition of each new facility, not only is aggregate travel minimized, but also a specified proportion of the population can be brought within easy reach of hospital services. This method is a particularly useful one because in planning the location of facilities, authorities hardly ever start off with a clean slate. Usually some facilities of the same kind might already be occupying some locations which may or may not be optimal. But whether or not the already existing network is optimal, the overall efficiency of the expanded network can be enhanced by proceeding in the manner outlined above.This method can be applied to a wide range of public facilities, like schools for instance. But its application depends, among other things, on the clear definition of locational and policy objectives. Different objectives could produce different locational patterns. Even variations in the measures of distance used can produce different locational patterns.     

Population pressure and land resource depletion in southeastern Nigeria

This paper measures farmland size per capita, fallow index and fragmentation index as indices of land resource depletion and population pressure in the heavily populated southeastern Awka-Nnewi of Nigeria. Population density in the area ranges from 574-2403 persons per square km, increasing annually at 3%. The soils are porous, sandy, with extensive gully erosion. Land is subdivided in each generation such that each male child receives a parcel of his father's land. There are other pressures on land parcels, notably for residential use. Soils have become depleted from intense cropping such that yams can no longer be grown and people subsist on cassava. Data were collected from 290 households in 36 towns and villages. The 3 variables were defined mathematically, and tabulated for each village. Then a correlation matrix was computed between the independent and dependent variables. All 3 variables, land per capita, fallow and land depletion, were significantly inversely correlated with population density (p.01), the fragmentation index to the greatest degree. All dependent variables were significantly and positively correlated. Scatter diagrams suggested that the worst hit areas were the central towns, and the least affected areas were the peripheral zones along the rivers and floodplains. Although federal regulations have been passed to make land redistribution easier, local custom makes it unlikely that people will resettle voluntarily to outlying areas because of traditions of land ownership. Similarly, government measures to encourage conservation and recovery of eroded land have not been successful, and food shortages are beginning to occur.     

Correlations, partitioning and bioaccumulation of trace metals between different segments of Taylor Creek, southern Nigeria

Correlations between trace metals in dissolved and particulate phases, B. bayad and sediments were investigated in five selected sites along Taylor Creek, which lies between longitude 006°17^I to 006°21^I E and latitude 05°01^I to 05°05^I N. The degree of correlation between the various metals was different in each of the investigated segments. Between segments, not many significant correlations were recognized. Only Ni and Cd, Mn and Cd, Mn and Ni, and Mn and Pb are correlated in the sediments and in the particulate phase, Fe and Cr, Pb and Cd, and Zn and Ni are correlated, which suggests that the sources are not common for both compartments. Partitioning coefficients (K_d) of trace metals between dissolved and particulate phases are generally low, which is typical for fresh water ecosystems and fairly stable over Taylor Creek all through the seasons. Furthermore, the bio-concentration factors (BCF) of B. bayad were low unlike those of other natural waters. Cluster analysis showed that metal accumulation in the particulate phase differed from those observed in sediments, which also confirms that the pollution of the Creek might be from different sources.     

Environmental Constraints and Part-time Farming in Southeastern Nigeria

In southeastern Nigeria where population pressure is a problem of accelerating importance the agricultural land is in short supply thereby necessitating off-farm jobs to supplement farm income. There is therefore, a high incidence of part-time farming in the region. Analysis of the operational characteristics of thirty-six villages confirms that the intensity of part-time farming varies spatially according to the severity of environmental degradation resulting from population pressure. In addition, villages around urban/industrial centres participate actively in part-time farming since opportunities for off-farm employment are relatively higher. The situation in southeastern Nigeria is used to illustrate the prospects and problems of part-time farming in a developing economy. The implications of part-time farming on the agricultural economy and on rural development generally are examined. Policy measures are suggested that will direct the co-existence of part-time farming with work in the off-farm sector in order to achieve a beneficial and integrated rural development.     

Changes in climate,vegetation cover and vegetation composition affect runoff generation in the Gulf of Guinea Basin

Although considerable effort has been deployed to understand the impact of climate variability and vegetation change on runoff in major basins across Africa, such studies are scarce in the Gulf of Guinea Basin (GGB). This study combines the Budyko framework and elasticity concept along with geospatial data to fill this research gap in 44 nested sub-basins in the GGB. Annual rainfall from 1982 to 2021 show significant decreasing and increasing trends in the northern and southern parts of the GGB, respectively. Annual potential evapotranspiration (PET) also shows significant increasing trends with higher magnitudes observed in the northern parts of the GGB. Changing trends in climate variables corroborates with shift to arid and wetter conditions in the north and south, respectively. From 2000 to 2020 vegetation cover estimated using enhanced vegetation index (EVI) shows significant increasing trends in all sub-basins including those experiencing a decline in annual rainfall. Vegetation composition measured using vegetation continuous fields (VCFs) from 2000 to 2020 show an increase in tree canopy cover (TC), a decline in short vegetation cover and marginal changes in bare ground cover (BG). Elasticity coefficients show that a 10% increase in annual rainfall and PET may lead to a 33% increase and 24% decline in runoff, respectively. On the other hand, a 10% increase in EVI may lead to a 4% decline in runoff while a 10% increase in TC, SV and BG may reduce runoff by 4% and increase runoff by 3% and 2%, respectively. Even though changes are marginal, decomposing vegetation into different parameters using EVI and VCFs may lead to different hydrological effects on runoff which is one of the novelties of this study that may be used for implementing nature-based solutions. The study also demonstrates that freely available geospatial data together with analytical methods are a promising approach for understanding the impact of climate variability and vegetation change on hydrology in data-scarce regions.     

松辽盆地徐家围子营城组流纹岩地球化学特征及构造指示意义

松辽盆地徐家围子营城组发育一套以流纹岩为主的中酸性火山岩。岩石薄片观察和主量、微量元素研究发现,后期热液蚀变、区域埋深及低温水合作用对流纹岩的Si、K、Rb等元素含量产生一定影响; 流纹岩明显富集Rb、Th、U、Pb等强不相容元素,Ba、Sr、Ti、Eu、P 负异常,暗示其经历了斜长石、磷灰石和钛铁矿分离结晶作用。流纹岩的(⁸⁷Sr/⁸⁶Sr)_i(0.705265 ~ 0.711895)值变化范围较大,大多数ε_Nd(t)为正值(1.83 ~ 3.38),Pb同位素比值相对集中,(²⁰⁶Pb/²⁰⁴Pb)_i=18.09～18.32,(²⁰⁷Pb/²⁰⁴Pb)_i=15.50 ~ 15.54,(²⁰⁸Pb/²⁰⁴Pb)_i=37.80 ~ 38.10。研究表明,岩石的源区为大比例年轻成分与少量古老地壳的混合部分熔融,其演化过程中经历了不同程度的地壳混染。松辽盆地早白垩世火山岩为板内伸展环境喷发的产物,可能与太平洋板块俯冲导致的中国东部岩石圈减薄、软流圈上涌密切相关。     

The population factor in public service provision in Nigeria

"This paper is concerned with ascertaining the impact of population on the spatial pattern of public service provision in Nigeria....Using a set of population and revenue variables as explanatory variables, a step-wise multiple regression model was employed to determine the impact of these variables on the provision of selected public services. The results of the analyses show that urban population is generally more important than total population in explaining the spatial pattern of public services. Generally speaking, the revenue variables are even more important in this regard, especially the internal revenue of states....One implication of these results is that ability to pay, rather than need, is the basis for public service provision in Nigeria. Thus, the richer and more developed states are better off than the less developed ones, irrespective of population size."