Rainforest Zone Research Articles

Soil fertility evaluation and land-use effects on soil properties, carbon and nitrogen sequestration in the rainforest of Nigeria

This study investigates changes in soil properties, specifically soil organic carbon (SOC) and total nitrogen (TN), associated with different land use systems derived from forests in the rainforest zone of Nigeria. The land use systems examined include mature oil palm plantation (OP), bush fallow or secondary forest (BF), alley cropping with multi-purpose trees (AC), and continuous cassava cropping with and without fertilizer (FC and UC). Converting forests to cultivated land led to a decrease in SOC and TN content and storage across all soil depths (0-10 cm, 10-20 cm, and 20-40 cm). In the top 0-10 cm depth, the average decrease in SOC and TN storage was 63% and 62%, respectively, while for 0-40 cm, the decrease was 48% and 46%, respectively, for all land use systems derived from forests. Furthermore, the study reveals that even after 5, 10, and 30 years of secondary forest regrowth (BF), alley cropping (AC), and oil palm plantation (OP), respectively, the fertility levels were not restored to those observed in the primary forest. These findings underscore the capacity of forest soils to conserve and enhance soil SOM (soil organic matter), which in turn plays an essential role in SOC sequestration, TN storage, and soil nutrient conservation.

Spatial heterogeneity of vegetation phenology caused by urbanization in China based on remote sensing

Vegetation phenology changes caused by urbanization could lead to shifts in ecosystem services in urban areas and impact on human health. The characteristics of urbanization affect vegetation phenology need to be emphasized, especially in China with a complex natural environment and rapid urbanization background. In this study, we used remote sensing-based phenological data (MODIS MCD12Q2) to analyze the spatial heterogeneity of vegetation phenology caused by urbanization between urban and non-urban areas in 320 cities across China. We found a significant difference between vegetation phenology in urban and its corresponding non-urban area at national and the regional scale. For national scale, the start of the growing season (SOS) was significantly advanced by 2.53 days (P < 0.001), and the end of the growing season (EOS) was significantly delayed by 6.72 days (P < 0.001), resulting in the growing season length (GSL) was significantly extended by 9.25 days (P < 0.001). For regional scale, the changes of SOS, EOS, and GSL caused by urbanization varied from seven vegetation zones in China. As expected for the Tropical monsoon rain forest and rain forest zone (TR) and Tibetan plateau alpine vegetation zone (TP), and Warm-temperate broadleaf deciduous forest zone (WTB), vegetation phenology in other four vegetation zones shows significant differences between urban and non-urban areas. Furthermore, the potential factors driving phenological changes through urbanization were discussed, which will be of great help in understanding the urban ecological process in future studies.

West African Dwarf goat populations of tropical rainforest zone: application of multivariate analysis tools on their characterization using morpho-biometric traits.

This research was carried out to characterize the West African Dwarf (WAD) goats using multivariate approach based on their morpho-biometric traits in the tropical rainforest zone of Nigeria. Data on four physical qualitative traits, six morphology indicators, and nine morphological characters were generated from 279 goats. Descriptive statistics, non-parametric analysis and one-way approach of ANOVA with post hoc tests, discriminant analysis (canonical), principal component analysis (categorical), and regression tree analysis were employed to discern the effects of location and sex on the parameters, as well as characterize the goats. The frequencies of the qualitative traits show black coat color predominated (60.2%) over other coat colors, plain color predominated (75.3%) over other color patterns, straight horns (38.1%) predominate over other horn shape, and beard presence (66.7%) predominated over non-beard presence among the goats in terms of locations and sexes. Location and age were significantly affected on the biometric characters (p<0.05 and p<0.001) with goats from Enugu having higher values than other states, while only head length (HL) was affected significantly by sex (p< 0.05). The morphological indicators were not significantly affected by location and sex (p>0.05 and p>0.001), while age was significant. The discriminant analysis revealed a sparse, non-intermingling populations for the physical traits, biometric characters, and body indices implying they are different distinct populations from each other. Generally, the goat populations could be characterized using heart girth (HG), rump height (RH), and body weight (BW) due to the principal components, while the CHAID and Exhaustive CHAID algorithm analysis revealed BW and HL as the genetic classifiers of the WAD goats, both in terms of locations. Basically, the goats from the 3 locations appeared to be more homogeneous in nature, implying that a deployment of specific complimentary genomics work targeted at future selection and breeding programs to improve their productivity in the tropical rainforest of Nigeria is necessary.

Socio-economic exploitation of edible caterpillars in the bimodal rainforest zone of Cameroon

Edible caterpillars are the most traded edible insects in Cameroon, particularly in the humid forest zone, where they are excellent sources of proteins and fats for many indigenous peoples. Their large consumption and their wild harvest have been a major concern, and there is a need for sustainable management. However, specific data on species’ diversity and trade are scarce. Hence, the present study aims to provide an overview of the socio-economic exploitation of edible caterpillars in the bimodal rainforest zone of Cameroon. Semi-structured interviews were conducted with caterpillar traders in six localities covering the three administrative Regions (East, Centre, and South) of the bimodal forest zone of Cameroon. The socio-demographic characteristics of traders, the traded species, quantities, and prices were recorded. Fresh and live samples were also recorded for morphological identification. A total of 129 traders were interviewed, with the majority being women (94.8%). Eleven species of caterpillars were involved in this trade, with the most remarkable diversity observed in the Centre Region. The traded quantity per species varied significantly with Regions, with the overall most exploited species beingImbrasia oyemensis (13,250.44 kg/year),Imbrasia truncata (4,992.30 kg/year) andAnaphe venata (2,589.51 kg/year). The price of caterpillars differed significantly depending on whether the locality was rural or semi-urban.Notodontidae sp. was the most valuable species (US$ 3.63/kg), followed by species of the genus Anaphe (US$ 3.1±0.5/kg). Special attention should be given to the most traded species to enhance their sustainable exploitation. Further studies on the bio-ecology, habitat and life cycle of these caterpillars are needed for the sustainable management of these beneficial insects. Forest authorities should enhance the regulations governing their exploitation and logging of their host trees.

Qualitative mutant traits within the indigenous chicken population in selected ecological zones of Ghana

A study was carried out to find out the various mutant traits present in the indigenous chicken population and their influence on egg production in the three ecological zones of Ghana. Four hundred and five (405) households were purposively selected across the Guinea Savannah, Semi-deciduous Rain Forest and Coastal Savannah ecological zones. Structured questionnaire and on-site interviews were used to obtain information from the local chicken keepers. The individual birds were phenotypically observed for the presence of the following genes; frizzle, naked neck, silkiness, polydactyl, ptilopody, crest feathered and flightless. Data on flightless chickens were not available except their gene frequencies since the respondents do not keep them for economic purposes. The data collected were organised and analysed such that phenotypic groups were considered as treatments and ecological zones as blocks. The frequency of the genes responsible for mutant traits were obtained from a count of the proportion of recessive in the sample using the Hardy Weinberg rule. The calculated gene frequencies for the mutant traits observed within the local chicken population ranged from 0.01 to 0.05 which differed significantly (p<0.05) from the expected Mendelian values of 0.75. Average clutch size per year, number of eggs set and chicks hatched per natural incubation were not significantly different (p>0.05) among the three ecological zones. The percentage hatchability for Guinea savannah and Coastal savannah were relatively higher compared to Semi-deciduous rain forest. In terms of phenotypes, polydactyl birds were significantly better (p<0.05) in average eggs per clutch per bird, number of eggs set for natural incubation and number of chicks hatched. Despite the low frequencies of these mutant birds, they had a higher potential for egg laying compared to their recessive counterparts.

Germination, Seedling and Early Growth of Monkey Kola (Cola parchycarpa) as Influenced by Different Organic Manures Mixed with Top Soil and White Sand in a Humid Tropical Rainforest Zone

Germination, Seedling and Early Growth of Monkey Kola (Cola parchycarpa) as Influenced by Different Organic Manures Mixed with Top Soil and White Sand in a Humid Tropical Rainforest Zone

Effects of Climate Change on Economic Growth: A Perspective of the Heterogeneous Climate Regions in Africa

Climate change is a negative global externality that threatens economic growth. In our study, we firstly reviewed the transmission mechanisms of climate change affecting economic growth based on existing literature. Secondly, we respectively used the fixed effect method and the panel vector autoregression method to test the short-run and long-run effects of climate change on the economic growth of 44 countries in six climatic zones in Africa, from 2000 to 2019. The results showed that temperature has inverted U-shaped effects on the economic growth of countries in tropical rainforest and tropical dry climate zones, but a U-shaped effect in warm temperate humid regions. The heterogeneity test was based on industrial and geographical perspectives. Climate change has a significant inverted U-shaped effect on agricultural and services output in tropical rainforest and tropical dry climate zones. Moreover, climate change positively impacts economic growth in coastal regions, but has no significant impact on inland countries. Lastly, the long-run results indicate that tropical rainforest and subtropical humid regions show a greater ability to adapt to climate change, while tropical desert regions show greater volatility resilience in response to climate change.

Runoff, Sediment Loss and the Attenuating Effectiveness of Vegetation Parameters in the Rainforest Zone of Southeastern Nigeria

The research was conducted to assess the pace of sediment loss in deserted 3-, 5- and 10-year-fallow traditional farmlands, as well as cultivated farmlands, in a remote forested zone in southern Nigeria. During the 2012 rainy and cropping season, field measurements of sediment and runoff caused by rainfall were carried out. Pearson’s correlation revealed that crown cover positively and significantly correlated with runoff on the cultivated farmland (r = 0.652, p &lt; 0.01). The results showed that the vegetation characteristics assessed on the different fallows explained 73.1%, 89.9%, 53.7% and 86.7% of the runoff variations. In addition, Pearson’s correlation demonstrated that girth explained sediment loss on the 5-year fallow (r = 0.807, p &lt; 0.01), while a strong positive and significant association existed between sediment loss and crown cover on the farmland plot (r = 0.835, p &lt; 0.01). The vegetation components were mutually responsible for 48.4%, 84.3%, 95.1% and 85.9% of the changes in sediment enrichment on the 5-year-, 10-year-, 3-year-fallow and cultivated farmland, respectively. The study found that mature/older fallows had a more substantial attenuating impact on soil erosion control than younger fallows.

Soil properties affecting soil organic carbon stock of different land use types in two agro-ecological zones of Nigeria

Soil organic carbon (SOC) stock is the carbon proportion that is of biological origin stored with respect to soil depth. It is more prone to loss than soil inorganic carbon. High sequestration of SOC in soil is germane to the improvement of soil quality and mitigating impact of climate change. Thus, this study was carried out to evaluate soil properties affecting SOC stock in the two agro-ecological zones, namely Upland Rainforest (Ado-Ekiti) and southern Guinea Savanna (Kabba) agro-ecological zones of Nigeria, with respect to three selected land use types; arable, oil palm and wetland. Random collection of soil samples was carried out at four varying depths (0-15, 15-30, 30-45, and 45-60 cm) for evaluation of soil properties. The SOC stock regression models for the two agro-ecological zones showed that land use, SOC, pH, SOM (soil organic matter), Ex-K, Ex-Ca, Ex-Mg (exchangeable potassium, calcium, magnesium, respectively), BD (bulk density), and gravel content would predict variation in SOC stock in the two agro-ecological zones with coefficient of determination (R2) values of 0.952 and 0.996 for Kabba and Ado-Ekiti respectively. Principal component analysis identified that in the soil of the southern Guinea Savanna agro-ecological zone, SOC, CEC, EA, Ex-Na, land use, clay content, and soil depth with Eigenvalues &gt; 1 explained 80.58% of sample variance while in the soil of the Upland Rainforest agro-ecological zone, Ex-Ca, SOC, Ex-Na, EA, sand and silt contents with Eigenvalues &gt; 1 explained 78.81% of sample variance as potential determinants of SOC stock.

Seasonal fluctuations of antioxidant enzymes and biochemical compositions of Apis mellifera adansonii L. from three ecological zones of Nigeria

BackgroundThe ability of honeybees to survive and sustain honey production depends on their ability to adapt to their environment. This study evaluated the seasonal fluctuations of antioxidant activities and biochemical compositions of honeybees, Apis mellifera adansonii L. from rainforest, guinea savannah and derived savannah zones of Nigeria during three seasonal periods (onset of rain, wet season and dry season) from January to December, 2017. Honeybees were collected from fully colonized colonies of two different apiaries from each of the ecological zones during the seasonal periods. Amino acid composition was determined using high-performance liquid chromatography. Antioxidant enzymes activity, body protein, glucose and lipid profile were evaluated using standard protocols.ResultsSeasonal periods showed significant (p < 0.05) effect on the eighteen amino acids, superoxide dismutase (SOD), triglycerides and fat-free nitrogen recorded in the honeybees. Amino acids were higher in the honeybees from the rainforest zone, regardless of the seasonal period. SOD and body protein were higher during the wet season in the three ecological zones. However, seasonal periods showed no significant (p > 0.05) influence on the body glucose, protein pattern, total cholesterol, activities of malondialdehyde, reduced glutathione, glutathione peroxidase and catalase. Body glucose content in the honeybees from the rainforest and guinea savannah zones was highest during the dry season.ConclusionsAntioxidant activities and biochemical compositions of honeybees are differently affected by both ecological zones and seasonal fluctuations.

Metal Fractionation and Leaching in Soils from a Gold Mining Area in the Equatorial Rainforest Zone

In this article, a modified BCR procedure and a column leaching test were used to examine the bioavailability and mobility of heavy metals in soils collected from a gold mining area in Ghana. The results for the fractionation of Cd, Cr, Fe, and Mn indicated that high percentages of metals were found in the residual fraction. This implies that the concentrations of metals in the soil are stable under normal environmental conditions. The bioavailability of metals in the soils declined in the following order: Mn (92.4%) &gt; Cd (64.6%) &gt; Cr (46.4%) &gt; Fe (39%). However, the concentrations of labile metals may pose no risk to the environment. In the column test, different rainwater conditions (i.e., natural rainwater and acidified rainwater) were used to imitate the leaching potential of the metals in the actual field. The pH of the soil primarily controlled metal migration into deeper layers. Cumulative metal concentrations in the leachates showed that Fe, Mn, and Cd were high in the tested soils but present at low concentrations, except for Cd. Cadmium showed a higher concentration than the WHO guideline for drinking water, and its seepage into deeper layers may affect the quality of groundwater.

Analysis of Land Use Change and Associated Implications on Soil Ecosystem Functions in South Eastern Nigeria

Land use change affects soil functions and its capacity to provide ecosystem services. Though much of the tropics are experiencing accelerated increases in land use change, associated impacts of such changes are poorly understood and studied. This study assessed the extent to which land use changes affect the soil ecosystem functions in a rainforest zone of south eastern Nigeria. Soil samples were collected from 24 sample locations in selected natural forest, cashew and palm plantations. Samples were analyzed in triplicate in the laboratory for geochemical analysis, after which the result was subjected to statistical analysis—ANOVA, correlation and regression. Forest carbon had higher % mean carbon content; though there was no significant difference (F (2, 21) = .246, p = .784) in carbon level across land uses. R value of .301 showed low correlation between % carbon, organic matter and % loss in ignition. Furthermore, R2 value of 9.1% total variation in the dependent variable could only be explained by the independent variables. CEC, Nitrogen, Potassium and Phosphorus content of the land uses did not differ significantly: CEC (F (2, 21) = .844, p (.44); Nitrogen (.243), p (.79), Potassium (.140), p (.87), Phosphorus (.783), p (.47). This showed that there was no significant variation in soil fertility of the land uses, although natural forest had higher concentrations for these variables. Across the land uses, soil texture equally had no significant variations: % sand (F (2, 21) = .320, p (.729) % clay (.430), p (.656), % silt (.043), p (.958). Soil carbon was seen to be more enhanced in natural forest ecosystems than other land uses. Though plantations had reduced capacities to provide ecosystem functions, establishing such in modified landscapes is still advocated as they can coexist with such and yet ensure ecosystem functions.

Precipitation Intensity-Duration Occurrence Models Development for Designated Locations in the Southern Humid Rain Forest Zones of Nigeria

This research work examined the tendencies and patterns in the rainfall in carefully chosen localities of Southwest and South-South Nigeria. Rainfall data from 1983-2014 in Ibadan, Lagos, Benin, Calabar, Port Harcourt and Warri were used for this study. Standard deviation, mean, coefficient of skewness, coefficient of kurtosis, coefficient of variation and standardized anomaly index were engaged to analyze the data and describe the distribution of rainfall in these stations. The data were analyzed using statistical package for social sciences, SPSS 17 and Minitab 16. The outcomes revealed that the maximum annual rainfall occurred at Warri station 4489.80 mm in the year 2008 and the minimum occurred at Benin 229.10 mm in 2005. Also, Benin has the maximum coefficient of variation of about 24.72%, while Port Harcourt has the minimum coefficient of variation of about 12.71%. Warri station was positively skewed indicating that it experienced frequent low rainfall values, while Port Harcourt was approximately symmetrical skewed. Warri has kurtosis coefficient of 4.45 which is highest among others. However, the patterns of rainfall in these areas are random or fluctuating. It is recommended that models built on the perceived decreasing rainfall, such as drainages, dams, have to be reviewed.

Effect of different fertilizers on yield and grain composition of maize in the tropical rainforest zone

This study assessed the quality of selected organic-based fertilizers (OBF) (neem-fortified (NM) and cow dung compost (CD)) and compared them with an inorganic fertilizer (IF) NPK 20-10-10 to determine the growth response and grain composition of maize. The field study was conducted in the early and late cropping seasons of 2015 at the Teaching and Research Farm of the Obafemi Awolowo University, Ile-Ife, Nigeria. The experiment, laid out in a randomized complete block design, consisted of six treatments: 100% NM and 100% CD, each at the rate of 3 and 6 t ha-1, IF at 0.3 t ha-1 (inorganic fertilizer recommendation for local maize production), and zero fertilizer application as control. The highest grain yield of maize (1.87 ± 0.13 t ha-1) was obtained with IF and the lowest one (1.01 ± 0.10 t ha-1) with zero fertilizer application. Maize grain yield from the repeated experiment without treatments applications reduced by about 50 and 75% for OBFs and IF and control plots, respectively. Low crude fiber, 2.62-4.13% obtained using OBFs was a good indicator of maize quality. Organic-based fertilizers demonstrated superior effects on the quality of maize grains when compared to the inorganic fertilizer.

Object-based characterization of vegetation heterogeneity with sentinel images proves efficient in a highly human-influenced National Park of Côte d’Ivoire

Forest monitoring requires more automated systems to analyze high ecosystem heterogeneity. The traditional pixel-based detection method has proven to be less and less effective. A novel change detection method is therefore proposed to detect changes in forest cover using satellite images at very high spatial resolution. This is object-oriented classification, which groups pixels into interpreted objects, based on their spectral values, spatial, and textural properties. Using sentinel and Lansat images, we tested for the first time in the West African rainforest zone the effectiveness of this method for better detection, delineation, and analysis of land use and occupation types. The mean shift algorithm was used in both the segmentation and classification processes. Next, we compared the proposed object-oriented method with a pixel-based image classification detection method by implementing both methods under the same conditions. High detection accuracy (> 90%) and an overall Kappa greater than 0.90 were obtained by the object-oriented method, which is about 20% higher than the pixel-based method. The object-based method was free of salt and pepper effects and was less prone to image misregistration in terms of change detection accuracy and mapping results. This study demonstrates that the object-based classifier is a much better approach than the classical pixel-based classifier. In addition, it shows the problems of detecting heterogeneous landscapes and explains the observed confusions between the types of vegetation formations specific to tropical wetlands. The results obtained are encouraging and the contribution of high-resolution images and the object-based method to better discrimination of tropical wetland vegetation is discussed.

FIBRE SOURCING FOR THE NIGERIAN PULP MILLS: EVALUATION OF SUITABILITY INDICES OF SELECTED NIGERIAN RAINFOREST WOOD FIBRES

To find a lasting solution to the problem of suitable fibre for pulp and papermaking in Nigeria, fibre suitability indices of nineteen wood species native to the rainforest zone of Nigeria were evaluated. Matured stems of the species were sourced and prepared for maceration. The fibre characteristics of the wood were carried out following ASTM D-1030-95 and ASTM D-1413-61. The fibres obtained were observed with the aid of a microscope and measurements of their morphology were done. A minimum of 25 fibres were measured for each species for accuracy. Selected morphological indices such as Runkel Ratio (RR), Flexibility Coefficient (FC), Slenderness Ratio (SR) as well as Rigidity Coefficient (RC) of the wood fibres were estimated. The results showed that the fibres lenght fall under short (1.05–1.36), medium-long (1.52–1.75), and long (2.0 mm) fibres criteria. All derived morphological indices showed significant variations from species to species. All fibres are not rigid and exhibited good SR with moderate rigidity and good felting power. They were all elastic; R. heudolotii and P. macrocarpa exhibited high elastic nature. They all have FC ≥ 50 and pass the RR ≤ 1, acceptable value for paper-making fibre except P. biglobosa and M. excelsa. The flexibility coefficients are in the range of 0.50 and 0.81. All the species pass the SR &gt; 33 acceptable value for paper-making fibres. The species if harnessed as fibre blends in pulp and paper making furnish will help to solve the problem of inadequate long fibres for paper production in Nigerian pulp mills.

Comparative Efficiency of Organic and Inorganic Fertilizers on Maize (Zea mays L.) Growth and Yield in the Rainforest Zone of Centre Cameroon

Maize is a major crop grown and consumed in the world and it requires a high fertilizer input. Although chemical fertilizers are an important input to get higher crop productivity, they have an impact on soil fertility, environment and human health. A field study was carried out to find alternatives to the mineral fertilization of maize. The aim of this study was to determine the influence of fertilizers on maize growth and yield while evaluating economic profitability. Four treatments (control, compost, poultry manure and mineral fertilizer NPK 20-10-10) and two maize varieties (local variety and improved variety CMS 8704) were used in a split-plot design with four replicates. Physicochemical analyses of soil and organic fertilizer were determined. Growth parameters, yield and acceptability index were evaluated. As results, poultry manure and compost are rich in nitrogen and phosphorus. At 9 weeks after sowing (WAS) the best stem diameter was obtained by the local variety in the plots fertilized with mineral fertilizer (2.83&amp;plusmn;0.31 cm). The yield of the CMS 8704 variety was significantly higher in the plots fertilized with poultry manure (2.23 t ha-1) than the yield of the local variety in the control plots (1.16 t ha-1). Principal component analysis (PCA) shows that compost and poultry manure were characterized by an increase in growth parameters as well as mineral fertilizer NPK. Poultry manure had the highest acceptability index of 1.25. In view of these results, it is clear that organic fertilizers; especially poultry manure, would have a positive impact on increasing maize production.

Evaluation of Plantain (Musa spp.) Varieties for Growth and Yield Characters in Humid Rainforest Zone of Nigeria

A field experiment was conducted to evaluate the growth and yield characteristics of plantain varieties in the humid rain forest zone of Nigeria. The research was conducted at the University of Uyo Teaching and Research Farm in Uyo, Akwa Ibom State, Nigeria. The objective of this study was to evaluate the performance of various plantain varieties with a view to identify high yielding genotypes. The planting material used for this study were the following varieties - 4479-1, 7152-2, Agbagba, Akpakpak, Mbiegome and a local cultivar called “Ogoni Red” obtained from the iInternational iInstitute of Tropical Agriculture (IITA), Onne, River State. Data collected on shoot and bunch yields characters were statistically assessed by analysis of variance. The growth characters showed significant variations among the plantain varieties. Plant height at 32 weeks after planting showed that variety 4479-1 recorded the highest height, 4.09 m while Agbagba and Mbiegome had heights 3.21 m and 3.07 m, respectively. The bunch characteristics measured after harvesting were statistically significant differences (P &lt; 0.05) among the varieties. The bunch weight differed significantly (P &lt; 0.05) amongst the varieties. The result showed that the yield (bunch weight) for Mbiegome was 10.55 kg, followed by 4479-1 with 10.28 kg., while 7152-2, Ogoni red and Agbagba varieties recorded 07.68 kg, 04.11 kg and 09.5 kg, respectively. In this study, variety Mbiegome outperformed other varieties in terms of yield and yield components apart from the finger thickness and length and is therefore recommended to promotion in Akwa Ibom State.

Insights from a Multi-Omics Integration (MOI) Study in Oil Palm (Elaeis guineensis Jacq.) Response to Abiotic Stresses: Part One-Salinity.

Oil palm (Elaeis guineensis Jacq.) is the number one source of consumed vegetable oil nowadays. It is cultivated in areas of tropical rainforest, where it meets its natural condition of high rainfall throughout the year. The palm oil industry faces criticism due to a series of practices that was considered not environmentally sustainable, and it finds itself under pressure to adopt new and innovative procedures to reverse this negative public perception. Cultivating this oilseed crop outside the rainforest zone is only possible using artificial irrigation. Close to 30% of the world’s irrigated agricultural lands also face problems due to salinity stress. Consequently, the research community must consider drought and salinity together when studying to empower breeding programs in order to develop superior genotypes adapted to those potential new areas for oil palm cultivation. Multi-Omics Integration (MOI) offers a new window of opportunity for the non-trivial challenge of unraveling the mechanisms behind multigenic traits, such as drought and salinity tolerance. The current study carried out a comprehensive, large-scale, single-omics analysis (SOA), and MOI study on the leaves of young oil palm plants submitted to very high salinity stress. Taken together, a total of 1239 proteins were positively regulated, and 1660 were negatively regulated in transcriptomics and proteomics analyses. Meanwhile, the metabolomics analysis revealed 37 metabolites that were upregulated and 92 that were downregulated. After performing SOA, 436 differentially expressed (DE) full-length transcripts, 74 DE proteins, and 19 DE metabolites underwent MOI analysis, revealing several pathways affected by this stress, with at least one DE molecule in all three omics platforms used. The Cysteine and methionine metabolism (map00270) and Glycolysis/Gluconeogenesis (map00010) pathways were the most affected ones, each one with 20 DE molecules.

Nodulation, dry matter accumulation and yields of soybean (glycine max L.) cultivars at varying plant spacing in a rainforest agro-ecology

Field trials were conducted during 2017 and 2018 late cropping seasons at the Teaching and Research Farm of the Faculty of Agriculture, University of Benin, in the rainforest zone of Nigeria to evaluate soybean (Glycine max L. Merrill) cultivars for nodulation, dry matter accumulation and seed and fodder yields at varying plant spacings. The trial was laid out in a randomized complete block design with split-plot arrangement replicated four times. Four plant spacings (50 × 30 cm, 60 × 25 cm, 75 × 20 cm, and 100 × 15 cm) were evaluated on six soybean cultivars: TGX1835-10E and TGX1987-62F (early maturing), TGX1951-3F and TGX1955-4F (medium maturing) and TGX1448-2E and TGX1904-6F (late maturing). Results showed that varietal performance depended on plant spacing. TGX1904-6F nodulated best at plant spacing of 50 × 30 cm, TGX1835-10E at 60 × 25 cm, TGX1987-62F at 75 × 20 cm, TGX1448-2E at 75 × 20 cm, and TGX1951-3 at 100 × 15 cm. TGX1835-10E accumulated dry matter most at plant spacing of 60 × 25 cm and 75 × 20 cm, TGX1987-62 at 75 × 20 cm, TGX1951-3F at 60 × 25 cm, TGX1955-4F at 60 × 25 cm and 75 × 20 cm, TGX1904-6F at 50 × 30 cm, and TGX1448-2E at 60 × 25 cm and 75 × 20 cm. TGX1448-2E and TGX1904-6F had higher seed and fodder yields at plant spacing of 50 × 30 cm, TGX1951-3F and TGX1955-4F at 60 × 25 cm, and TGX1835-10E and TGX1987-62F at 75 × 20 cm, relative to other plant spacing. Therefore, for higher yields in rainforest agro-ecology, farmers should adopt the right cultivar-plant spacing combination for soybean.