Desert Encroachment Research Articles

LOSS OF BIODIVERSITY AND FOOD SECURITY IN NIGERIA

Nigeria is rich in biodiversity, boasting of diverse ecosystems and numerous species. The country's ecosystems range from semi-arid savannas to montane forests, floodplains, rainforests, freshwater swamps, and coastal vegetation. However, Nigeria's rich biodiversity, essential for agriculture and food security, is under severe threat, impacting adversely on food security. This study investigates the impact of oil pollution, deforestation, and desert encroachment on biodiversity loss within Nigeria's agricultural ecosystems. This study employed a comprehensive review of existing literature on the assessment of biodiversity loss in Nigeria's agricultural ecosystems due to pollution from oil spill, deforestation and desert encroachment. By analyzing the correlation between these environmental stressors and food security challenges, this study highlight the critical need for integrated conservation and agricultural strategies. The findings indicate that the loss of biodiversity has far-reaching implications, including malnutrition, food price volatility, and the erosion of rural livelihoods. The study emphasizes the pressing necessity of tackling these challenges in order to guarantee sustainable food security and ecological equilibrium in Nigeria. To address these interconnected issues, the study recommends a holistic approach that prioritizes sustainable practices, robust policies, and community engagement. By safeguarding Nigeria's biodiversity, we can ensure a sustainable food future for generations to come.

Economic Impact of Trypanosomosis on Camels (Camelus Dromedarius) in North-West, Nigeria

Desert encroachment accelerated by global warming threatens the lives and livelihood of scores of farming families. However, camels can withstand the harsh climatic conditions and provide draught power thereby supporting subsistence agriculture and other economic activities. This study aimed to investigate the economic-impact of camel Trypanosomiasis (Surra) in two communities in North-West, Nigeria using structured questionnaires. All the 99 respondents interviewed were males and over 30 years of age with majority of them having Islamic/Quaranic education. The economic impacts identified include death (42%), poor milk production (38%) and reduced draught power (38%). The mean prices of live camels differ between the two study areas; ₦301,928.57 vs. ₦128,100.00 and ₦184,377.55 vs.₦82,100.00 for healthy adults and young camels in Kano and Katsina states, respectively. About 38−54% loss in value of live camels estimated at ₦114,581.63−₦164,755.09 in Kano and ₦48,850−₦76,100.00 in Katsina was attributed to Surra. Similarly, Surra is believed to account for over 90% loss in milk production in camels, where an estimated daily loss of over ₦7,000.00 was recorded. Although the estimated impacts were based on the opinion of a few randomly selected respondents, the huge financial cost associated with Surra is alarming and deserves attention. It is evident that this disease threatens food security and impedes the achievement of sustainable development goals. These findings bring to fore the socioeconomic importance of Surra in the study area and call for the formulation of cost-effective control measures.

Spatio‐Temporal Dynamics of Aboveground Biomass in China's Oasis Grasslands Between 1989 and 2021

AbstractGrassland provides multiple ecosystem services and plays a key role in preventing desert encroachment and maintaining oasis stability. In China, the area of cropland in oases has expanded significantly in recent decades, which results in a rapid increase in agricultural water demand and encroachment on grassland subsistence space. However, our knowledge about how the expansion of cropland affects oasis grasslands remains limited. We used machine learning, temporal segmentation of spectral trajectories, and maximum covariance analysis to generate an annual oasis grassland aboveground biomass (AGB) data set at 30‐m resolution from 1989 to 2021 based on multiple remotely sensed and ground observation data sets, and investigated the dynamics of grassland AGB under cropland expansion in oases. We found that overall oasis grassland AGB increased significantly (0.3 gm−2 yr−1, P < 0.01) during 1989–2021, but trends in AGB were not consistent across basins. In the Yellow River, Turpan Hami, Qaidam, and southern Altai Mountains River Basins, AGB was dominated by a significant increase. Conversely, in all basins in southern Xinjiang, AGB showed a decreasing trend due to the rapid cropland expansion. Spatially, cropland expansion and AGB dynamics were strongly coupled. In regions characterized by agricultural concentration, grassland AGB benefitted from resource spillover via edge effects. However, in downstream areas or those with a low proportion of cropland, where most grasslands are distributed, the relationship between the two shifted to a trade‐off. Our study provides a scientific basis for identifying priority areas for ecological restoration and for science‐based planning of the scale of cropland in oases.

A Review on Medicinal and Ethnomedicinal Uses, Biological Features, and Phytochemical Constituents of Sesbania sesban L. Merr., A Nitrogen-Fixing Plant Native to the Republic of Chad.

This study reports on a literature review of the leguminous tree Sesbania sesban (L.) Merr which is found in the N'djamena region, the Republic of Chad. The study focused on S. sesban's medicinal and ethnomedicinal uses, biological features, and phytochemical constituents to assist in future evaluations. A literature review was conducted using academic websites, such as Science Direct and Springer, online international plant databases, and data from national herbaria. S. sesban is a perennial shrub or tree that measures 3-4 m in height. This species is becoming rare in N'djamena but can be found in the rainy season, while in winter, it occurs mainly in ponds (called the Chadian dialect "Bouta") and on the shores of the Chari and Logone rivers. The local inhabitants in Chad use the species as medicine, livestock feed, and fuelwood and for improving soil fertility and repelling desert encroachment. Traditional healers use its leaves to treat breast cancer and edema. S. sesban is an essential species native to the Republic of Chad that needs conservation and valorization. Viewing its importance and rarity in N'djamena , a strategy for replanting the species in gardens, homes, and fields around N'djamena and other regions of Chad is recommended.

CONSTRAINT CURRENT CONTROL FOR GRID-CONNECTED POWER INVERTER

Recent study has paid much attention in the areas of renewable energy (solar and wind) as an alternative method to derive electrical power rather than going by fossil fuels (coal, natural gases etc.) which constantly emits carbon dioxide and other harmful substances into the atmosphere. The emission of these undesirable harmful substances into the atmosphere have caused climatic changes for example global warming, acid rain, low precipitations and unwanted desert encroachment. These badly affect the quality life of humans and animals. In response to these problems, methods of reducing carbon content emissions become necessary through the use of renewable energy sources (Photovoltaic system, Wind power, Fuel cell etc.). As a result, research on grid-connected inverter have recently become a very hot topic as a means of interfacing renewable energy sources to utility grid. With good interfacing, the renewable energy sources can be able to solve not only the problem of carbon emissions into the atmosphere but also to efficiently support the grid from increased demand of electrical power. Thus, this research has focused on designing a constraint current controller for grid-connected inverter using linear quadratic regulations (LQR) method. The idea of using LQR control design as opposed to classical PI controller is that The LQR provides optimal current control by careful tuning of the input and state weighting matrices and therefore systematic control design can be achieved. Another advantage of LQR method is that constraint handling can be address through an offline optimization technique. This is necessary in order to protect the inverter system components (semiconductor switches) and improve its reliability.

DETECTING VEGETATION LOSS AND ITS ECOLOGICAL IMPACTS USING GEOSPATIAL TECHNIQUES IN POTISKUM LOCAL GOVERNMENT AREA, YOBE STATE, NIGERIA

Ensuring good management and sustainability of natural resources is paramount for future generations to thrive and live in cleaner and safer environment. This research examines the land use/land cover changes over three decades (1990 to 2019) in Potiskum using geospatial techniques. The Land use and land cover changes of the years 2010 and 2019 showed a continuous trend of vegetation being converted to cultivated areas while cultivated areas are converted to built-up areas. The findings show significant changes in vegetation cover across the study area between 1990 and 2019. Specifically, the years 2010 and 2019 witnessed a significant reduction in vegetation cover of 38% compared to 1990 and 2000 which reveals a decrease of 14.5%. From 2000 to 2010, a decrease of 8% in the vegetation cover was found. Cumulatively, the vegetation loss in the study area was found to be 60.5% between 1990 and 2019. This is highly significant and almost irreversible due to the fragile nature of the environment. The several causative factors responsible for the vegetation loss include intensification of agricultural activities, deforestation, rapid urbanization and exponential population growth. These causative factors have led to many ecological impacts such as drought, desert encroachment, sand storm, flooding, rise in temperatures, soil erosion and rainfall variations. The research recommends afforestation and reforestation measures, legislation on sustainable utilization of natural resources, tree planting campaign and subsidies on alternative sources of energy.

Desertification in the Sahel Region: A Product of Climate Change or Human Activities? A Case of Desert Encroachment Monitoring in North-Eastern Nigeria Using Remote Sensing Techniques

Desertification has become one of the most pronounced ecological disasters, affecting arid and semi-arid areas of Nigeria. This phenomenon is more pronounced in the northern region, particularly the eleven frontline states of Nigeria, sharing borders with the Niger Republic. This has been attributed to a range of natural and anthropogenic factors. Rampant felling of trees for fuelwood, unsustainable agriculture, overgrazing, coupled with unfavourable climatic conditions are among the key factors that aggravate the desertification phenomenon. This study applied geospatial analysis to explore land use/land cover changes and detect major conversions from ecologically active land covers to sand dunes. Results indicate that areas covered by sand dunes (a major indicator of desertification) have doubled over the 25 years under consideration (1990 to 2015). Even though 0.71 km2 of dunes was converted to vegetation, indicative of the success of various international, national, local and individual afforestation efforts, conversely about 10.1 km2 of vegetation were converted to sand dunes, implying around 14 times more deforestation compared to afforestation. On average, our results revealed that the sand dune in the study area is progressing at a mean annual rate of 15.2 km2 annually. The land cover conversion within the 25-year study period was from vegetated land to farmlands. Comparing the progression of a sand dune with climate records of the study area and examining the relationship between indicators of climate change and desertification suggested a mismatch between both processes, as increasing rainfall and lower temperatures observed in 1994, 2005, 2012, and 2014 did not translate into positive feedbacks for desertification in the study area. Likewise, the mean annual Normalized Difference Vegetation Index (NDVI) from 2000 to 2015 shows a deviation between vegetation peaks, mean temperatures and rainfall. On average, our results reveal that the sand dune is progressing at a mean annual rate of about 15.2 km2 in the study area. Based on this study’s land cover change, trend and conversion assessment, visual reconciliation of climate records of land cover data, statistical analysis, observations from ground-truthing, as well as previous literature, it can be inferred that desertification in Nigeria is less a function of climate change, but more a product of human activities driven by poverty, population growth and failed government policies. Further projections by this study also reveal a high probability of more farmlands being converted to sand dunes by the years 2030 and 2045 if current practices prevail.

ALDO LEOPOLD’S LAND ETHIC AND DESERTIFICATION IN NORTHERN NIGERIA: AN ETHICAL APPROACH

This work is on Aldo Leopold’s Land Ethic and desertification in northern Nigeria: An Ethical Approach. Desertification is a global environmental problem that has affected both developed and developing countries in various parts of the world. Nigeria is one of the countries south of the Sahara faced with fast desert encroachment, with notable effects on the northern part of Nigeria. The study showed that desertification has been experienced and reported in the northern part of Nigeria since the 1920s, but its effect or impact has been glaring since after the famine of 1971–1973. The problem this work looks at is the issue of desertification in northern Nigeria. Consequently, the study looks at the problem of desertification in Nigeria and analyses it with Aldo Leopold’s Land Ethic. This work employed the method of content analysis to get a clarification of Aldo Leopold’s Land Ethic and how it can be applied to the problem of desertification. The analytic method was also used to look at the concept of desertification. The work also pointed out that the government has not done enough to curb this environmental menace peculiar to those in the northern part of Nigeria. The work was able to establish that anthropocentric activities are the major causes of desertification, and it was further revealed that desertification is seriously affecting northern Nigeria. In conclusion, the work recommends that the government should not just make environmental laws but should also go further to ensure that the people are guided by these laws, that is, by enforcing them.

The Concept of Desertification, Its Causes and Effects, and Treatments

Since the United Nations General Assembly passed two resolutions in December 1974, the term "desertification" has become a part of international development discourse: The first is a call to all countries to pay attention to desertification research and work together to explore its causes and find strategies to prevent it. The decision to organize an international conference on desertification in 1977 was the second. From August 29 to September 9, 1977, the conference was held in Nairobi, Kenya. The term "desertification" seems to have taken the place of prior words like "desert encroachment." Perhaps what we witness when desert sand dunes creep over oasis communities and farms and fill them, as well as when sand dunes crawl over paved highways and trains, contributes to this picture. This is a genuine depiction, however it only depicts a small portion of the problem (less than 10%). The word "desertification" refers to the process by which productive land outside of the desert's natural limits deteriorates and loses its capacity to produce (agricultural crops, pastures, timber and fuelwood) and transforms into a desert that resembles a limited resource. Desertification, in other words, impacts productive lands in dry and semi-arid locations, agricultural fields (rain-fed or irrigated), and grazing lands. The degradation begins as little patches that get larger and more like expanding patches until they converge and combine, becoming an arid band that joins the deserts of the surrounding places as it becomes more like them.

ENVIRONMENTAL AND HEALTH EFFECTS OF CLIMATE CHANGE IN KADUNA METROPOLIS

This study examined environmental and health effects of climate change in Kaduna metropolis. Primary data were obtained through randomly administered 184 structured and semi structured survey questionnaires to purposefully selected groups of people, workers and students in the metropolis. Secondary data were obtained from desk reviews of other literatures and interviews of staff of Nigerian Metrological (NiMET) Agency and Ministry of Environment Kaduna. Descriptive statistics using Likert rating scale was employed for the analyses of the data. Findings revealed percentage range of strongly agree and agree of 80% - 59.8% that climate change has negative environmental and health effects in Kaduna metropolis. The environmental effects identified are: flooding, desert encroachment, drought, land degradation, run-off, soil erosion, loss of water resources and biodiversity and poor agricultural productions while the health effects are: hyperthermia, vector and water borne diseases (cholera, malaria), heart ailments, dehydration and diseased crops. The study also discovered that the comprehension of the concept climate change in the metropolis is limited. Finally, the study recommends intensive public education and enlightenment on the causes and effects of climate change, strong legislations and enforcement of environmental laws and adaptation measures.

Climatic Water Balance Over Two Climatic Periods and Effect on Consumptive Water Need of Selected Crops in the Chad Basin, Nigeria

Agriculture is a critical part of Nigeria’s economy as it employs a large proportion of the population. However, climate change is a threat to agriculture in many parts of Nigeria especially the north-eastern part where the Lake Chad basin is a prominent victim. Yet, the Lake Chad basin is crucial to food security in Nigeria as most of the grains are grown there. Thus, prudent management of water resources and agricultural planning is required to ensure the sustainability of crop production in the basin. This study applied the Thornthwaite water balance model to compute the water balance of select crops in the basin to devise a better farming practice based on the findings. The study period was divided into two, the base period (1945–1979) and the second period (period of change 1980–2014). The findings show that there is a significant change or variability in climate between the two periods. However, the change is higher in Nguru which may be due to its higher latitudinal location and the desert encroachment due to poor land-use management. However, with the proposed bi-annual cropping of the select crops, it is possible to have double seasons of planting in the study area. The first season will be from May–September and the second from October–February. Since the water need of these crops is not so demanding, the crops can be grown twice with prudent water management via rainwater harvesting and minimal groundwater withdrawal. Further studies are suggested to work out the irrigation schedule for the different crops to minimise waste and losses due to over-irrigation. Hence, it is recommended that improved seed crops with very short growing cycle and/or drought-tolerant species as well as developing all-year-round planning is a panacea to human and environmental concerns in the basin.

Farmers’ Climate Change Understanding and Mitigation Strategies in Kebbi State, Nigeria

The challenges of climate change are increasingly becoming major issues of concern to many regions in the world. Despite reduction in agricultural outputs, rapid diseases outbreak, shortage of rainfall and desert encroachment are serious negative consequences associated with climate change. In local communities in Nigeria, farmers adapt certain fundamental strategies as an approach toward enhancing farm production despite the menace. The research therefore surveyed the understanding of climate change, its causes and consequences among 500 farmers in Kebbi state located in north-western Nigeria. The results of this study found that many farmers are not aware of the tragedy but experienced its negative impacts. However, among farmers with good understanding of the problems, fundamental steps were been applied to ensure land protection and boost agricultural outputs. The study further explained the measures required to elevate situation awareness among respondents as a key to addressing climate change.

Climate Change and the Political Economy of Fish Production in the Lake Chad Basin

The world is overwhelmingly confronted with the challenges of climate change and extreme poverty, both of which are on the rise globally with the increasing dependency on fossil fuel for energy. Among the implications is the high level of dryness, rise in sea level, desert encroachment, and among others. Even so, water bodies such as lake, bonds and tributaries are the most affected. This is evidenced with the rapid shrinkage of the Lake Chad (LC) which sustains over 30 million people across 4 countries. The fast disappearing of the sixth-largest inland water body in the world and the largest endorheic Basin in Africa which is of paramount importance as an agricultural heartland has resulted to food insecurity, hunger, and poverty in the Lake Chad Basin (LCB). Against this background, the paper examines the impact of climate change on fish production in the LCregion. It creates a nexus between the shrinkage of the LC water body and the reduction in fish production in the LCB. Theoretically, the study anchored on social production and reproduction as a framework of analysis. Relying on the documentary method of data collection, the paper found that the rise in global temperature accounts for the rapid disappearance of the LC water from more than 25,000km 2 in the 1970s to less than 2500km 2 presently. The paper also found that the due to this shrinkage, the region is experiencing a sharp decline in the output of fish production, and consequently, reduction in the income level and GDP of the fishing communities of the LCB. Based on these findings, the study recommended that the Lake Chad Basin Commission (LCBC) should initiate a program for an annual transfer of water from either River Congo or the Atlantic Ocean into the LC in other to save the endorheic freshwater lake from drying up.

Effects of different media strengths and hormone concentrations on in-vitro regeneration of <i>Vitellaria paradoxa</i> C.F. Gaertn

The importance of Vitellaria paradoxa has necessitated its inclusion in the ongoing afforestation project which requires mass production of its seedlings. The shea-butter tree produces oil-rich seeds that are important to cosmetic and food and nutrition industries. It is a deciduous tree which could survive in the dry-savannah and help withstand desert encroachment. However, overexploitation of its timber for firewood and charcoal production made it vulnerable. In-vitro propagation of this species could be a viable means towards its mass propagation. Two plant-hormones: Gibberellic Acid (GA3) and Benzyl Amino Purine (BAP) were used to grow the plant in different combinations making up six treatments (A-F) with 6 replicates in each group. The combinations include 1.5/0, 1.5/1.0, 1.5/1.5, 2.0/0, 2.0/1.0, 2.0/1.5 mg/L of GA3/BAP, which were used to grow 2cm nodal cuttings of the V. paradoxa on half-strength Murashige and Skoog (MS) media. Treatment F (with 2.0/1.5 mg/L GA3/BAP) produced the highest number of leaves (2.4 ± 0.6, 3.2 ± 0.8) and longest shoot length (1.1 ± 0.3 cm, 1.4 ± 0.5 cm) at 4 and 8 Weeks After Inoculation (WAI), respectively. The results of this study showed that application of growth- enhancing hormones for the regeneration of important tree species could provide means for their mass propagation so as to meet the need for afforestation projects.
 Keywords: Vitellaria paradoxa, Afforestation, In-vitro propagation, Mass propagation.

From blue to green water and back again: Promoting tree, shrub and forest-based landscape resilience in the Sahel

Enjoying the potential climate benefits of restoration requires linking key forest-water and land-atmosphere interactions to the existential benefits provided on the ground. We apply what we call the "forest-water and land-atmosphere interaction lens" to current strategies for improving landscape resilience in the West African Sahel and the concept of the Great Green Wall (GGW). The severe and extensive drought of the 1970's–1990's led many to assess future climate and promote strategies to counter the gradual southward expansion of the Sahara. The idea for the GGW, a wall of trees intended to slow desert encroachment, grew out of this period of tremendous upheaval and human tragedy. Despite partial recovery in the local rainfall regime, we know far too little about whether the GGW strategy can even work. Further, it seems disingenuous to ignore the climatic envelope, which sets the boundaries within which forest-water and land-atmosphere interactions occur. Applying the “forest-water and land-atmosphere interaction lens” to landscape restoration as a tool for achieving improved resilience and human welfare in the Sahel provides meaningful input for re-thinking the GGW strategy. We upgrade current knowledge with the specific biophysical conditions likely to better support appropriate forest-water and land atmosphere interactions in the region and further fit such approaches within the context of the climatic envelope. The principal components of an improved strategy include a focus on large scale precipitation recycling all the way from the West African coast on into the Sahel, as well as improved tree, shrub and forest cover in the Sahel proper to promote infiltration, groundwater recharge, rainfall triggering potential and land surface cooling. Agroforestry can further broadly promote landscape resilience in the greater region. Strategies broadly focused on increasing rainfall recycling, water availability and the promotion of landscape resilience appear more likely to steer future efforts in useful directions.

Impact of Climate Change on Arable Crops among Farmers in Akko Local Government, Gombe State, Nigeria

The study was conducted on the impact of climate change on arable crops production among farmers in Akko Local Government Area of Gombe State, Nigeria. A multistage sampling method was adopted selecting one hundred and fifty respondents. Both primary and secondary data were collected covering a period of five years. The data collected were subjected to descriptive statistics. The research found that male farmers within the age bracket of 20-40 years dominate the farming system, with 62.2% being married and having one form of formal education or the other. The result indicated that 92.9% of the respondents are aware of climate change and are predominantly small land holders. The farmers highlighted increased in drought period, higher temperature, erosion, desert encroachment, loss of vegetation and reduced vegetation as effects of climate change. It was revealed that 92.9% of the respondents’ cropping patterns have been affected by climate change. To cope with these effects, farmers diversify their enterprises. The findings show that farming activities such as deforestation, clean clearing, bush burning, open grazing contributes to climate change. The amount of rainfall experienced from 2015-2019 in the area was moderate. The respondents use farmers’ saved seed as planting materials with 62.2% comprising of improved seed. The result indicates that over 95% of the sampled population uses synthetic and organic fertilizers in soil management. From the result, 52.0% of the respondents obtained good yield during the period under study. However, farmers engaged in different cropping systems to mitigate the effect of climate change. It is recommended that extension services should be improved to educate farmers more on adaptation strategies to increase output; Research Institutes should develop more advance or improved seeds as well as disseminate same to farmers timely and adequately.

Deforestation, desert encroachment, climate change and agricultural production in the Sudano-Sahelian Region of Nigeria

This work presents a systematic review of relevant literatures centered on the deforestation, desertification climate change hazards and agriculture related problems caused as a result of these natural and human activities with the hope of understanding the situation for better way out. Findings revealed that desertification affects about one sixth of the world’s population, 70% of all dry lands, amounting to 3.6 billion ha, and one quarter of the total land area of the world. The worsening problem of desertification is quite glaring that an estimate of between 50 % and 75 % of Adamawa, Bauchi, Borno, Gombe, Jigawa, Kano, Katsina, Kebbi, Sokoto, Yobe, and Zamfara states in Nigeria are affected by desertification and are particularly vulnerable to wind erosion due to land clearing for agricultural purposes such as grazing, planting of crops, demand for woods, mining, growth of urbanization and development of infrastructures. Desert encroachment as a degradation of land in arid, semi-arid and sub-humid dry areas caused mainly by climatic changes and human activities; In Nigeria, the dry land parts of the country are more prone to desertification. However, climate change causes uncertainties and variation in the pattern of rainfalls, high temperatures, floods and farmlands destruction, pests and diseases. Leading to irregular and unpredictable rains and increase in sunshine hours, crops and livestock failures as well as food insecurity in general. It was suggested therefore that effective policy and planning measures should be put in place in order to overcome these problems.Keywords: Deforestation, desert encroachment, climate change, agriculture

Ants invading deserts: Non-native species in arid Moroccan oases

The oases of Morocco, located between the Mediterranean and the Sahara ecoregions, constitute the main defence system of the temperate region against desert encroachment. This study aims to determine species richness and distribution of native and non-native ants in the oases of southern Morocco. Survey campaigns were conducted in 11 oases between March and May 2017. Thirty-four ant species belonging to 13 genera and three subfamilies were collected. The regional catalogue of Formicidae is enriched by 27 new species (total 44 species) and five were listed as non-native species (11.4% of diversity). The most frequent species is Pheidole pallidula and the richest oasis is Allogoum (containing 11 species of which two are exotic and three are native and exclusively detected here). Of the 11 studied oases, only four were free from non-native ant species. Regression-based methods indicated that species diversity of non-native ants is related to water availability and total flow rate of sources, and only total flow rate of sources for all species combined. All correlations become non-significant when non-native species are removed from analyses, suggesting a recent colonisation and early invasion. Water availability is necessary to maintain local myrmecological diversity. This study sets the basis for future identification of the impacts of non-native ants on the ecological integrity of oasis ecosystem and to establish conservation measures.

Effects of planting Caragana shrubs on soil nutrients and stoichiometries in desert steppe of Northwest China

Caragana korshinskii shrubs are widely planted in desert steppe of Northwest China to mitigate desert encroachment. Soil nutrients and stoichiometries reflect the cycling of soil organic matter in ecosystems. Thus, there is a dynamic balance between soil nutrients and stoichiometries due to the establishment of Caragana shrubs in this region. Here, soil nutrients and stoichiometries were characterized with different planting densities of Caragana shrubs (HD, high density, 4530 bundle/hm2; MD, mid density, 3670 bundle/hm2; LD, low density, 2560 bundle/hm2) to explore how the planting of Caragana shrubs affects soil nutrients and stoichiometries in desert steppe of Northwest China. The results showed that soil available phosphorus (AP) and soil total phosphorus (TP) had no significant differences between LD and control (CK) (p > 0.05). Further, soil organic carbon (SOC), soil total nitrogen (TN), and soil alkali-hydrolyzable nitrogen (AN) followed the order of HD > MD > LD > CK, indicating that the planting of Caragana shrubs had an increasing effect to soil nutrients, with the exception of AP and TP (p < 0.05), and the increasing effect gradually died down along soil profile. In addition, the planting of Caragana shrubs significantly affected soil stoichiometries. Specifically, soil N/P and C/P gradually increased with soil depth with fluctuation, while soil C/N decreased with soil depth. Besides, soil water content (SW), AP, AN, and SOC had strong positive effects on soil C/N, while they had strong negative effects on soil C/P and N/P, highlighting the importance of soil properties in determining soil stoichiometries. Overall, our results indicated that planting Caragana shrubs can improve levels of soil nutrients, and HD can be considered the optimal planting density for vegetation restoration in desert steppe. Nevertheless, the threshold of the planting density most favorable for the special climates must be identified through further study in this region.

Industrial Development and Natural Resources Depletion in Nigeria

A number of Nigeria’s natural resources are being depleted at very fact rates, making their availability unsustainable for sustainable industrial development. The Nigerian soils are generally light texture and low in Cation Exchange Capacity (CEC) which ranged from 2.40 to 5.95 mc/100g of soils. Various soil fertility studies have shown that most Nigerian soils have pH ranges from 4.2 to 8.4 with a combined calcium content which varies from 0.5 to 5.55nc/100g and generally low potassium content (0.07 to 0.45) and an organic matter that varies from 1 to 2.55%. The level of micronutrients are low with fertility and productivity indices varying between 31-90% and 2-58% in most cases. Soil fertility and nutrient content are fast depleting by various factors which includes low use of mineral fertilizers, gully erosion, soil salinity, desert encroachment and others such as inappropriate agricultural practices, oil spillage, over population and lack of land use planning. Also, on the increase is groundwater depletion, deforestation which occurs at about 300,000-400,000ha per annum, loss of biodiversity which is threatening 484 plant species in 112 families of the 4,600 plant species in Nigeria. Fisheries resources are also depleting. Both the inland freshwater and the oceans are experiencing serious onslaught of the fish population with species such as the Atlantic cod and haddock already depleted in the salt waters. On the inland waters, fish production is being decimated on annual bases with production in the 80’s less than half of the 1950’s. The mineral resources have been mined since 1906. Currently, large scale exploration of limestone, marble, rock aggregates along with gold, oil and gas are on-going causing a lot of havoc to the environment. There is need to halt or reduce these occurrences in order to put industrial development on a sustainable path. Keywords : natural resources, depletion, minerals, biodiversity, deforestation. DOI : 10.7176/JESD/10-4-06