Evaluation of Four Anthropogenic Activity Impacts on Heavy Metal Quality of the Kumba River in the South West Region of Cameroon

Anthropogenic activities have contributed to pollution of water bodies through deposition of diverse pollutants amongst which are heavy metals. These pollutants, which at times are above the maximum concentration levels recommended, are detrimental to the quality of the water, soil and crops (plant) with subsequent human health risks. The objective of the work was to evaluate the impacts of human-based activities on the heavy metal properties of surface water with focus on the Kumba River basin. Field observations, interviews, field measurements and laboratory analyses of different water samples enabled us to collect the different data. The results show four main human-based activities within the river basin (agriculture, livestock production, domestic waste disposal and carwash activities) that pollute surface water. Approximately 20.61 tons of nitrogen and phosphorus from agricultural activities, 156.48 tons of animal wastes, 2517.5 tons of domestic wastes and 1.52 tons of detergent from carwash activities were deposited into the river each year. A highly significant difference at 1% was observed between the upstream and downstream heavy metal loads in four of the five heavy metals tested except for copper that was not significant. Lead concentrations were highest in all the activities with an average of 2.4 mg∙L−1 representing 57.81%, followed by zinc with 1.596 mg∙L−1 (38.45%) and manganese with 0.155 mg∙L−1 (3.74%) for the different anthropogenic activities thus indicating that these activities highly lead to pollution of the Kumba River water. The level of zinc and manganese was significantly influenced at ρ 005 by anthropogenic activities though generally the variations were in the order: carwash (3.196 mg∙L−1) < domestic waste disposal (3.347 mg∙L−1) < agriculture (4.172 mg∙L−1) < livestock (4.886 mg∙L−1) respectively and leading to a total of 14.04 tons of heavy metal pollutants deposited each day.

Agro-Morphology Evaluation and Gluten Content Estimation of Wheat (Triticum aestivum L.) in the Western Highland of Cameroon

Agriculture is amongst the major occupations in Cameroon where over 70% of citizens are involved and it contributes enormously to the economy of the country. Wheat is one of the most consumed cereals in Cameroon with very high importation rate. However, the adoption of wheat production in the cropping system could have the potential to pull farmers out of poverty. It is essential in human foods and animal feeds. This study aims to investigate on the adaptability of wheat varieties based on growth traits and yield as well as to estimate the gluten content in each of the tested variety in the North-West region. Eight wheat varieties (five from CIMMYT, two from IRAD and one local variety) were evaluated in a factorial design with two types of fertilization (organic and inorganic), in two site (Santa and UBa farm) and five environments. Agro-morphological data were collected and were subjected to the analysis of variance using R software. The gluten content related to the baking quality of wheat flour was estimated per tested variety. Highly significant differences were observed among varieties, sites, environment and fertilization for all parameters estimated. The general mean of all the traits evaluated was significantly higher when using organic fertilizer than inorganic, meaning that the application of organic fertilizer provides better performance of wheat growth. The elevated number of tillers found in Santa could inform on the high level of soil fertility for wheat production in that area. Environment 1 was found to be the best follow by environment 3 and 5. IRAD I gave the highest yield followed by Alexander Wonder and IRAD II. 11SATYND and 29SAWYT were promising introduced varieties in term of grain weight when using organic fertilization. Wet and dry gluten yield varied from 3.8 (ALEXANDER Wonder) to 5.5 (IRAD I) and from 3.7 (IRAD II) to 7.9 (IRAD I) respectively. All the introduced wheat varieties expressed low wet and dry gluten yield as compare to the check Amigo. IRAD I was the best variety to be produced for industrial purposes taken into account the high level of gluten content. IRAD I, 42ESWYTB and IRAD II were found to have their moisture content percentage of flour below that of the check (Amigo) and therefore could be recommended for manufactured foods.

Comparative Study of the Widal Test against Stool Culture in the Diagnosis of Suspected Cases of Typhoid Fever in Some Low Income Communities in the Adamawa Region of Cameroon

Introduction: Infectious diseases constitute a major concern of public health in developing countries. Facilities and well trained staff have been shown to be one of the major obstacles in the rapid and quality diagnosis of these diseases. As such, we carried out an analysis to compare the Widal test and stool culture to identify febrile patients with Salmonella infection. Method: A cross sectional study was conducted to diagnose salmonella infection with out-patients who demonstrated signs of salmonella infection. Serum was harvested from blood collected from 368 (Vina = 234, Mayo Banyo 65, and Djerem = 69) patients accompanied by stool, Widal test was conducted on the spot and stool was taken to a reference laboratory for culture using standard microbiological methods, sociological set up was calculated in percentages, prevalence was calculated using excel while statistical difference was calculated using SPSS. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to compare the Widal test against stool culture. Results: A total of 368 (50.8% females and 49.2% males) participants took part in the survey. Salmonella prevalence (66.24%) in stool culture in the Vina division was significantly different (p 0.05). The sensitivity,specificity, PPV, and NPV of slide agglutination test against stool culture varied from different areas (Vina: 51.6%, 73.62%, 79.21% and 43.61%;Mayo Banyo: 60.53%, 77.78%, 79.31% and 58.33%;Djerem: 53.18%, 83.73% 73.91% and 67.39%) respectively. Slide agglutination test has a fair agreement with the stool culture (kappa, Vina = 0.202;Mayo Banyo = 0.37 and Djerem = 0.38). Conclusion: Generally, in the three areas of study, the Widal test had a fair correlation with the stool culture;This means the Widal test should not be used alone but in combination with stool culture in the detection of salmonella infections.

Mobility of Major and Trace Elements during the Bauxitization Processes in Ngaoundal Area (Adamawa Cameroon): Implication on Mining Perspectives

This study was focused to assess major and trace elements in bauxitic duricrusts from Ngaoundal and its surroundings in order to establish their mining interest. To this end, fieldworks, mineralogical and geochemical analyses were carried out. Four facies of duricrust were identified and characterized from the summit to the top of the slope of the Ngaoundal mountain: scoriaceous, pisolitic, nodular and massive. Mineralogical and geochemical analyses performed on 16 samples, revealed a significant concentration of Al2O3 mainly in the scoriaceous facies (over 45% in grade), moderate in Fe2O3 (averaging 23.69%) and SiO2 (averaging 21.7%). Trace elements were generally low, excluding Cr (421 ppm on average), Zr (327 ppm on average and V (213 ppm on average). In addition, the limited quantities of alkalis (Na2O, K2O) and alkaline earths metals (MgO, CaO) coupled with the very high values of Chemical Index of Alteration (CIA) and Mineralogical Index of Alteration (MIA), (more than 99%) attest to the intense weathering of the studied materials. Allitization and monosiallitization constituted the crystallochemical phenomena that have led to the development of bauxitic minerals. More than 90% of gibbsite in scoriaceous facies, 52.21% - 76.01% of kaolinite in pisolitic facies and more than 40% of hematite in nodular facies were quantified. The relationships between the constitutive components indicated their interdependency during the bauxitization phenomenon. The mineralogical and geochemical properties highlighted the mining interest of the studied duricrusts to be valorized.

Farmers’ Knowledge and Awareness towards the Use of Agrochemicals in Vegetable Cultivation, Fako Cameroon

Agrochemicals are contemporary, omnipresent tool used in vegetable cultivation. Farmers’ knowledge and awareness of the proper usage of agrochemicals are critical for mitigating the negative effects on human health. This cross-sectional study was aimed at assessing the usage knowledge, risk awareness of toxicological and chemical classes, proper handling and use practices for agrochemicals homologated for use in vegetable farming, and the occurrence of health-related symptoms as a result of exposure among these farmers. The study included 93 vegetable growers from agricultural hotspot towns in Fako, southwest Cameroon. The field study, ran from November 2021 to December 2023, using a questionnaire to collect information on farmers demographic, and their knowledge of pesticide classes, and the related risk of associated with the handling of agrochemicals. Results show that all vegetable farmers, particularly those engaged in agribusiness, employ pesticide inputs to maximize production. Six pesticides, two fertilizer types, and one unknown substance were identified. While 23 active compounds were found, the most utilized were abamectin, emamectin (10.46%), dimethoate (9.30%,) and ethoprophos (8.13%). Two active chemicals, dimethoate and methalaxyl, are illegal yet remain in circulation. Toxicological classes I and II, with the greatest harmful effect on human health, were the most commonly utilized (64.27%). Thirty-nine percent of farmers never use personal protection equipment when working with agrochemicals, demonstrating a significant gap in knowledge and awareness of agrochemicals and their various applications and handling procedures in the field. The government should implement an intensive specialized educational program for on-field farmers with incentives in order to promote sustainable agriculture methods that ensure environmental and human safety.

Physicochemical Characterisation of Flours from Local Cereals and Powder from Cassava (Manihot esculenta Crantz) Leaves Varieties Cultivated in the Northern-Cameroon in Order to Supplement Infant Flours

The aim of the present study was to investigate on the inventory and determination of the nutritional value of cereals flour and cassava leaves powder in order to analyse their use in the production of infant flour. In this paper, a A survey to identify the cereals used in the preparation of infant porridge in the Northern Cameroon was done by using 447 mothers having children between 06 and 59 months from areas (Gbakoungue, Sassa-Mbersi, Sanguere-Ngal and Kotkong-Wouldata) with high rate on malnourished children. Flour was prepared from the most preponderant cereals and Cassava leaves powder from varieties identified by the Regional Centre of Agricultural Research (CRRA) of Wakwa and local population. Flour and powder samples obtained were subjected to chemical composition analysis. Parameters analysed were crude proteins, total carbohydrates, ash, total fats, total phenols, total tannins, total carotenoids, vitamin C or cyanide. Also Iron, calcium and zinc were determined. The results revealed that white maize (62%) was the main cereal used in the preparation of infant porridge followed respectively by red sorghum, white rice and muskwari. Ten cassava varieties were identified: three (03) by CRRA (TME, 96/1/14 and IRAD 4115) and seven (south, gambada, sweet, Benin, six months, M. glaziovii and grouna) by local population. Amongst cereals flour, those from white maize indicated high protein (10.09%), carbohydrates (84.46%) and total fat (7.46%) contents. The powder from 96/14/14 cassava variety showed high amount of iron (11.98 mg/100g), calcium (751.02 g/100g) and low cyanide content (1.21 ppm) amongst all the cassava leaves powder samples. The supplementation of white maize flour by cassava leaves powder from 96/14/14 variety could therefore be recommended for the preparation of infant flours.

Floristic Diversity and Conservation Status of Guineo-Congolese Species in Southeastern Cameroon: The Case of the Gari-Gombo Communal Forest

The conservation of plant biodiversity has become one of the most important objectives in the sustainable management of Guinean-Congolese ecosystems. However, in the south-east zone of Cameroon, there is a lack of rigor in the management of these forests, which can result in the loss of species of high conservation value. The study was carried out in communal forests in the south-east zone of Cameroon. Its aim was to carry out a floristic inventory and then compare the list of species with the IUCN catalog. Twenty-four plots, each with a surface area of 0.2 ha, were set up in the Gari-Gombo communal forest. All timbers with a DBH ≥ 5 cm were systematically counted. A total of 176 species, belonging to 144 genera and 45 families, were surveyed. Fabaceae (42.08%), Malvaceae (39%), Euphorbiaceae (24.64%), Moraceae (20.92%), Apocynaceae (18.64%), Cecropiaceae (16.60%), Ulmaceae (14.76%), Meliaceae (14.61%), Violaceae (14.08%), Combretaceae (12.67%), Theobroma cacao (21.17%), Baphia leptobotrys (18.06%), Rinorea sp. (14.09%), Musanga cecropioides (12.18%), Terminalia superba (10.32%), Neosloetiopsis kamerunensis (10.14%), Celtis zenkeri (8.29%) and Alstonia boonei (7.77%) were the most important taxa. Nearly 90% of the species in this forest are Guinean species, with a dominance of Guinean-Congolese species (66%). Fourteen (14) threatened species have been identified in the FCGG. This study, which highlights the rich biodiversity of communal forests, is important for guiding biodiversity conservation policies in ecosystems used for production.

Floristic Diversity in Forest Management Units: Implications for Biodiversity Conservation in FMU 09-025

The assessment of floristic composition and diversity is very important in forest management units. This study sets out to determine the species diversity and implications for biodiversity conservation in FMU 09-025 of the Campo Ma’an National park, South Region of Cameroon. Due to human activities in the area, the study site was divided into two Blocks (A and B). The transect method was employed in data collection. A total 14 long transects were established parallel to each other in blocks at a distance of 3 km apart, 8 transects in Block A and 6 Transects in Block. In each transect, plots of 20 × 500 m were established at intervals of 500 m. Within each plot, all individual trees ≥ 10 cm were identified, measured, and recorded. The DBH of all trees were measured at 1.3 using the DBH meter tape. The height of trees was measured through estimation (average estimates of all field researchers). Results revealed a total of eight thousand one hundred and twenty four (8124) individual plants with DBH ≥ 10 cm in the entire study area. From this number, 5113 tree stems ≥ 10 cm were identified and measured in Block A. This belongs to 216 species in 47 families. In block B a total of and 5011 stems were identified and measured. This belongs to 239 species in 47 families. Fabaceae, Annonaceae, Euphorbiaceae and Rubiaceae were found to be the most dominant plant families in the study site. Erythrophleum ivorense, Lophira alata, Dialium bipindense, Musanga cecropioides, Alstonia boonei, Pterocarpus soyauxii, Guibourtia ehie, Staudtia kamerunensis, Desbordesia glaucescens, Sacoglottis gabonensis were found to be the most dominant plant species. 41 species are of conservation concern according to the IUCN global Red List 2023 and IUCN local status. These species are considered species with high-priority for conservation. We have 6 endangered species, 11 near Threatened species, and 25 vulnerable species. There was no significant difference in species diversity in the two Blocks.

A Gender Analysis on the Participation and Choice of Improved and Local Haricot Bean (<i>Phaseolus vulgaris L</i>.) by Farmers in Cameroon

Men and women farmer participation and choice of variety could guide breeding and drive the adoption of different haricot bean varieties. Thus, understanding how gender influences participation and choice of bean cultivation and marketing is fundamental. The study sought to analyse how socio-cultural norms determine women and men, participation and choice of variety for cultivation and sale in Cameroon’s West region. A mixed-method was used in collecting data from men and women farmers in six subdivisions in the West region of Cameroon in 2019. Result reveals that women provide most of the labour on haricot bean production than men, who are more involved in selling to national and regional markets. Participation and role were driven by socio-cultural norms of what is expected of men and women in a society where women provide food and men income for household upkeep. Women preferred varieties that were less labour intensive and food taste for household consumption while men went for labour intensive as long as they were market-oriented and high yielding. Thus, breeders should develop varieties that are mostly preferred by women, which meet the market and household demand.

Impact of Organic Soil Amendments on the Physical Characteristics and Yield Components of Potato （Solanum tuberosurn L.） in the Highlands of Cameroon

A field experiment was conducted in the Western Highlands of Cameroon to study the effects of Calliandra calothyrsus, sterilized compost, non-sterilized compost and mineral fertilizers （NPK 11：11：22） on physical characteristics, yield components and late blight disease severity of potato （Solanum tuberosum）. A two factorial treatment combination made up of fertilization schemes and sanitary measures were laid out in a randomized complete block design （RCBD） with four replicates and 10 treatments. Data collected were subjected to a multivariate ANOVA and means separated with the Dunnett t-test with Calliandra calothyrsus considered as the main treatment. Mineral fertilizers and Calliandra calothyrsus significantly augmented stem diameter, plant height and plant vigor, total and marketable yields, despite the fact that late blight severity was high in the two treatments. The correlation matrix showed that total yield had significant and positive correlation with stem diameter （r = 0.74）, plant height （r = 0.61）, plant vigor （r = 0.61） and marketable yield （r = 0.99） and negative correlation （r = -37） with late blight severity. The increase observed is attributed to the nutrient contents of the treatments applied. Leafy prunings of C. calothyrsus increase soil organic matter which probably improves moisture retention and biological activity. The highest late blight severity recorded between the 45 and 60 coincides with active development of plant canopy which influences disease severity and create a canopy microclimate conducive to disease development. This study suggests that Calliandra calothyrsus has the potential of improving potato production provided appropriate fungicide is used.

Understanding Seasonal and Spatial Variation of Water Quality Parameters in Mangrove Estuary of the Nyong River Using Multivariate Analysis (Cameroon Southern Atlantic Coast)

To evaluate the actual status of water quality and conclude on the mains source of pollution in the Nyong estuary River, seasonal and spatial variation of water quality parameters was interpreted by multivariate statistical techniques (Principal Component analysis). Nine (09) environmental variables were monitored at four surface stations in the estuary for two seasonal cycles. The fieldwork was conducted from 2018 to 2019 during high tide and low tide for each survey. In situ physical parameters were measured for a total of 64 samples (32 samples for each tide). The laboratory works consisted of some physicochemical analyses and processing of these data by descriptive and multidimensional statistical analyses. Temperature, suspended particle matter, nitrate, nitrite and phosphate change significantly in the estuary with season (p < 0.05), while salinity, dissolved oxygen, pH, and ammonium do not vary significantly with season (p > 0.05). Principal Component analysis found temperature, salinity, pH, ammonium to be the most important parameters contributing to the fluctuations of surface water quality in the Nyong estuary during the dry seasons whereas suspended particle matter, nitrate, and phosphate are the most important parameters contributing to the fluctuation of surface water quality in the Nyong estuary during the rainy seasons. Based on spatial variation, the Principal Component analysis found that, suspended particle matter, nitrate and phosphate contribute to the fluctuation of surface water quality parameters upstream of the estuary while downstream salinity, pH, and ammonium contribute the most to the fluctuation of surface water quality. This study shows us the usefulness of multivariate statistical techniques used in assessing water quality data sets that would help us in understanding seasonal and spatial variations of water quality parameters to manage estuarine systems.

Impact of Heart Rot of <i>Pericopsis elata</i>(Harms) Van Meeuwen on Yield at Harvest in Production Forests in South-Eastern Cameroon

This study of the impact of heart rot of Pericopsis elata on logging yield was conducted in Libongo, in three logging concessions of the Société d'Exploitation Forestière et Agricole du Cameroun (SEFAC). An inventory of 92 P. elata stumps in four Annual Cutting Areas (AACs) divided among three Forest Management Units (FMUs) distinguished by Minimum Operating Diameter (MOD) revealed that 22 stumps were rotten. Decay was visible on stumps with a diameter of more than 100 cm with a frequency of occurrence of 23.91%, a percentage of abandonment of 55.20% and a yield of 44.79%. The most important economic loss was revealed on 9 abandoned whole logs that cumulated a volume of 145.547 m3. The correlation between the diameter of the stumps and that of the decay gives a coefficient or correlation rate r = 0.31. The MOD for P. elata could be 80 cm and covers the biological risk class. The results indicate that P. elata shows an increasing gradient of decay rate with increasing tree diameter, resulting in a loss of material for larger diameter trees, and consequently a decrease in material yield at processing.

Development of a Technical Itinerary for the Production of Avocado (Persea américana Mill.) Seedlings with Biofertilizers

The cultivation of fruit trees generally requires a nursery phase during which the young seedlings are monitored and treated to improve their ability to adapt to the environment. This leads to the production of seedlings that are used to create orchards. It consists of four essential steps or operations: 1) The germination phase of the seeds in germinators for the production of rootstocks;2) Transplanting into pots or bags;3) Fertilisation in order to obtain seedlings of a satisfactory vigour (stem diameter) ready for grafting. The nursery phase requires a good understanding and mastery of plant regeneration and fertilisation techniques. In Cameroon, the demand for avocado (Persea americana) fruits is increasing, but the supply is not keeping up with this demand. After a summary monograph on the production practices of avocado seedlings in the Yaounde area, this work aims to optimise the aforementioned three steps in order to obtain seedlings of sufficient sizes for grafting. Three factors are considered in this study: 1) The substrate (Substrate), whose effects are evaluated by the germination rate (GR), the daily average germination (DAG) and the root volume of seedlings (RootV). 2) The transplanting date (TransD), determined by considering three dates including 40 (Trans40), 65 (Trans65) and 75 (Trans75) days after sowing, and 3) Fertilisation using biological fertilisers, evaluated by testing four fertilisation levels, Fert1 (10 gr of 20-10-10 plus 10 gr fowl droppings), Fert2 (Acaulospora tuberculata), Fert3 (Gigaspora margarita) and Fert4 (Mixed mycorrhizal strains of Gigaspora margarita and Acaulospora tuberculata). This third factor is evaluated by growth parameters including leaf area (LeafA), chlorophyll index (ChlorInd), gain in Plant height (GainPltH) and plant diameter (GainPltD). The trial took place in the First Seed company, a seed production unit located in the Simbock district of Yaounde for the field phase, and the Biological Control Laboratory of the Institute of Agricultural Research for Development (IRAD), Nlolbisson, Yaounde. Two trials were conducted, the first with the objective of determining the best substrate with a completely randomized block design in 2 replications, three substrates/replication. The second trial was done with a factorial design (Split plot) with three replicates, the main factor being the Transplanting Date (TransD) and the second factor the biological fertilizer. Data were separated using least significant difference at 5% treshhold. Results indicate a highly significant effect of substrate on RootV (p = 5.00E-03). This effect translated by an increase of 49.42% and 19.53% of root volume on sawdust respectively to sand and soil. Sawdust (100%) and soil (98%) affect germination by 8 days reduction over sand and the germination rate on these two substrates is higher than the one on sand (92%). The early transplanting (TransD40) allows a better growth of the seedlings in terms of stem length and the collar diameter. The only observation variable that stands out for the early nursery stage fertilisation is leaf area, which shows significant differences between the 4 fertilisation formulae tested. The chlorophyll index and leaf area are also strongly correlated with the seedling growth parameters. Our results show that the early transplanting stage (40 days after planting) combined with a germination on white sawdust should be proposed to reduce the production cycle of grafted seedlings in association with early application of biofertilisers or organic fertilizer.

Potato (Solanum tuberosum L.) Flour Enriched with Date Palm Fruit (Phoenix dactylifera L.) Powder and Bean Milk for Cookies Production

This study emphasizes the formulation of three types of cookies viz potato flour with date powder and bean milk (PDBM), potato flour with sugar and bean milk (PSBM), and potato flour, sugar, and eggs as control. After the substitution, the highest protein content was observed in PDBM (1.78 ± 0.12)% followed by PSBM, (1.35 ± 0.01)% and the lowest was in the control (0.91 ± 0.55)%. Moreover, cookies fortified with date palm powder increased the carbohydrate and fat contents compared to the control and significantly increased the calorific value of PDBM. The formulated cookies were significantly higher (p < 0.05) in iron (39.95 ± 3.00) mg/100 g and zinc (13.65 ± 1.61) mg/100 g in PDBM compared to other cookies. The date palm powder incorporated in cookies significantly increases the darkening of biscuits during cooking. The organoleptic characteristics of PDBM and PSBM were rated overall best when specific parameters were tested. With the shortage of wheat and importation constraints, an alternative provides a great market opportunity for local products like potatoes and beans. In addition, fortifying food products as cookies eaten by all will contribute to a more food and nutrition-secured world.

Effect of Grafting on Growth and Shelf Life of Tomatoes (Solanum lycopersicum L.) Grafted on Two Local Solanum Species

The Rio Grande variety of tomato is widely grown because of its high productivity during the cold and dry seasons, and its resistance to Verticillium wilt (caused by Fusarium oxysporium) and to stem canker (Alternaria). Grafting tomato onto compatible rootstocks resistant to these diseases offers a better potential to overcome soil-borne diseases, abiotic stresses, improve growth, yield and fruit quality. However, in Cameroon, there is little or no information on grafting between Rio Grande tomato and selected eggplant rootstocks. The objectives of this study were: 1) To determine the compatibility between Rio tomato grafting and a popular local eggplant (Nkeya) rootstock;2) To verify the effect of grafting on flowering time;3) To evaluate the effect of eggplant rootstocks on growth, fruit shelf life and fruit quality of Rio tomatoes. The trial was conducted in a randomized complete block design with 3 replications. Rio Grande (To) was the ungrafted treatment used as a control. To/Ko, To/To and To/Nk were the grafted treatments eventually transplanted to the field. Growth data were subjected to analysis of variance using SPSS software. Descriptive analyses were performed for the other parameters. The results revealed that, 1) The cleft grafting method used was successful with success rate varying between 90 and 100%;2) Grafting influenced flowering date (DAT, p = 0.05) as well as tomato growth parameters including stem height (H, 1.49 × 10-10 p 0.00014) and collar diameter (SD, 4 × 10-14 p 0.009). The To/To treatment was significantly different from the ungrafted cultivar To, which had no significant difference in stem diameter. A significant difference in plant height was also observed between the ungrafted treatment To and the To/Ko and To/Nk treatments. In addition, only the collar diameter of To/Nk was different from To. Also, there was no significant difference between To/To and To, but a significant difference between To/Ko and To/Nk compared to To. Conversely, grafting improved the lifespan of To/Ko. Ultimately, the grafting method used was successful, but further studies are needed to overcome the problem of graft incompatibility in order to improve the agronomic performance of grafted plants.

Cultivar and Soil Fertilizer Treatment Affect Seed Production of Sweet Yellow Yam (<i>Dioscorea dumetorum</i>) on Highly Acidic Soils of the Western Highlands Region of Cameroon

The popularization of Dioscorea dumetorum (Dioscoreaceae), a nutritious yam species is still marginal due to constraints such as the low interest of research, poor cultural practices, insufficient and expensive seeds, pests, and diseases. The latter pushes producers to use about 50% of their harvest as seed for the next planting season. The lack of a specific fertilizer formulation for yam production on the oxysols of Cameroon is another constraint. This study was aimed at enhancing the availability of quality seeds through the characterization of five yam accessions. One experiment was performed to determine the effect of cultivar and origin of tuber sets on their germination rate. The second concerned the evaluation of cultivars and soil treatment effects on agronomic parameters of yam seedlings. Yam cultivars were subjected to nine fertilizer formulations as follows: T0: no fertilizer;T1: mycorrhizal fungi (MF) + 150 g manure + peanut waste;T2: 25 g chemical fertilizer (20.10.10);T3: MF + peanut waste;T4: 16 g chemical fertilizer (12.6.20);T5: 25 g (20.10.10) +100 g CaO + 150 g manure;T6: 100 g CaO + 150 g manure;T7: 20 g tropicote + 2 g DAP (Diammonium phosphate, a reference starter fertilizer coded N18P46) + 100 g CaO + 150 g manure;and T8: mycorrhiza. These treatments were tested in a factorial design. Results show that Ibo sweet 3 and Mabondji sweet white 1 yam accessions were less affected by anthracnose disease on the aerial parts. Guzang 1 showed the best germination rate and yield, making it appropriate for cultivation in the region. Soil treatments, T2, T5, T7 and T8 significantly increased the yield of yam cultivars. Mycorrhiza treatment alone gave a better response to seed weight, indicating the interest of this biofertilizer as a solution for good seedling production. These fertilizer treatments can be recommended to farmers for more seed production with optimum seed weight (300 g).

Effects of Different Levels of Fertilization with Hen Droppings on the Production and Chemical Composition of <i>Pennisetum clandestinum</i>(Poaceae)

The use of organic manures, constitute an alternative to that of polluting artificial fertilizers. In this study, the effect of various levels of hen droppings fertilization on the production of biomass, chemical composition and carrying capacity of P. clandestinum were evaluated at the Research and Experimental Farm (REF) and at the Animal Nutrition and Feeding Laboratory of the University of Dschang, between April and September 2016. A completely randomized block design comparing three nitrogen level of fertilization in hen droppings form (0;100 and 200 kg N/ha) on 4 m2 plot of P. clandestinum were used. Each treatment was carried out in four replications for a total of 12 experimental plots. Then a sample of 500 g of forage has been collected in the center of each plot, then dried and used for the evaluation of the biomass and the chemical composition of P. clandestinum, according to the level of fertilization and the cutting frequency. The results showed that the fertilization with the hen droppings positively influenced (p < 0.05) regeneration at the first cutting frequency and the highest value (47.12 cm) was obtained with of 200 kg N/ha rate of fertilization. The biomass of this fodder increased significantly (p < 0.05) with the level of fertilization with hen droppings. Besides, it decreases with the increasing cutting of frequency whatever the level of fertilization. Independently of the fertilization and the cutting frequency, the maximum biomass (6.22 t DM/ha) was obtained with the first cutting at the 200 kg N/ha of hen droppings fertilization. The fertilization influenced in variable way the chemical composition of P. clandestinum. The dry matter and organic matter content decrease with the level of fertilization and the highest values (83.79% and 89.39% respectively for the DM and OM) were obtained on the control plot at the third and the first cutting. Moreover, the ash and crude protein contents increased significantly (p < 0.05) with the cutting frequency of cutting and the level of fertilization applied. The highest ash (19.34% DM) and CP (20.04% DM) contents were obtained with of 200 kg N/ha of hen droppings at the second cutting frequency.

Farmers＇ Perceptions of Soil Fertility Status in the Savannah Zone of Centre Cameroon

In Cameroon, most farmers rely on their perceptions for fertility evaluation and choice of agricultural land units. However, because of environmental change, this knowledge is mostly disregarded. The use of farmers＇ knowledge is important for the identification of relevant information for the choice of agricultural land units. The objective of this study was to compare farmers＇ perceptions of soil fertility with a conventional scientific approach in two locations of the forest margin zone of Center Cameroon. Through interviews and soil analysis, this study spelled and weighed the relationships between farmers＇ perceptions and soil fertility status. One hundred and twenty households＇ heads were interviewed and 30 soil samples collected. Farmers＇ perceptions were used to assess the topsoil fertility status across the studied areas, while a conventional scientific approach was used to quantify soil fertility status by the means of a soil fertility index （SFI）. Results showed that farmers, for soil differentiation, used color, texture, depth, drainage and vegetation. Soil＇ names delivered key messages for their location. Although the low overall SFI approximated by the conventional approach, farmers＇ perceptions could differentiate fertility levels between soils. This knowledge is relevant for the design of technical innovations in perceived fertility niches.

Changes in Some Nutritional and Mineral Components of Nerica Rice Varieties as Affected by Field Application with Mycorrhiza and Chemical Fertilizer in Northern Cameroon

Rice as staple food is the most important and valuable cereal crop in Cameroon, particularly in rural areas where poor population cannot afford to cook and eat at their convenience. With the outbreak of Nerica varieties, it is important to evaluate and compare their nutritional and mineral properties to those of the local ones prior to their vulgarisation. Therefore, some nutritional and mineral properties of 4 Nerica and a local seeds varieties used in this study were harvested from control (T0), chemical fertilizer (TE), mycorrhiza (TM) applied plants, or their mixture (TEM). These seeds originating from Wakwa and/or Yagoua experimental sites were assessed and compared in a split-plot design (4 × 5) × 3 between treatments (4) and varieties (5). The local DIR-95 variety had values close to those of Nerica varieties in all the parameters assessed. Protein contents ranged from 17.66% - 24.35%, and was higher than those reported in rice samples elsewhere. All the studied varieties were classified as high amylose rice, and therefore, their textures in cooked form should be less sticky and harder, which is convenient to the diet behavior of many consumers. The relative low Fe content in Nerica rice suggest that these varieties may be resistant to Fe accumulation in seeds. The P, N, Mg contents were found to be more elevated in seeds harvested from mycorrhiza or chemical fertilizer applied plants, with Nerica seeds variety FKR62-N as the best of all in nutrients mineral and nutritional compositions. These results confirm varietal and site influences on proximate and mineral contents in the studied rice varieties.

Agriculture and Soil Management in the Context of Sustainable Development in the Sudano-Sahelian Zone of Cameroon

The Sudanian-Sahelian zone of the Far-North Cameroon faces an extreme climate challenge resulting in increased vulnerability to erosion, soil degradation, and the effects of climate change, impacting soil fertility and agricultural yields. The objective of this study was to analyze agricultural practices, challenges related to climate change and soil degradation, as well as the solutions adopted by farmers to address these issues. To achieve this, 600 farmers from the six departments of the region were interviewed. The results highlight the significant impact of climatic conditions on soil health, agricultural activities, and food security. Farmers identified various indicators of soil degradation, including agricultural yields, bioindicator plants, plant growth, soil fauna, and root density. The main causes of soil degradation are associated with practices such as deforestation, intensive agriculture, the use of chemical fertilizers and pesticides, overgrazing, and the effects of climate change. The impacts of this degradation are multiple, including soil fertility loss, reduced agricultural yields, deforestation, reduced biodiversity, income loss, water resource pollution, and food insecurity. In response to these challenges, farmers have adopted sustainable soil management practices, including crop rotation, intercropping, fallowing, the use of organic fertilizers, and the adoption of conservation agriculture. To effectively address these challenges, concerted collaboration between farmers, civil society organizations, and government authorities is imperative to develop sustainable and effective solutions against soil degradation in the region.