Soil quality and soil fertility status in major soil groups at the Tombel area, South-West Cameroon

Open Access Journal; Published online: 27 Feb 2020Among the greatest challenges of Sub-Saharan Africa is the need for more crop production for supplying the increasing demand of its growing population. For this purpose, knowledge on soil resources and their agricultural potentials is important for defining proper and appropriate land use and management. We thus investigated on the status of soil fertility in Tombel area, in order to produce such knowledge through understanding and monitoring the impact of physicochemical properties of soil. Diverse analyses performed on various datasets demonstrated the direct impact of physicochemical properties of soil and derived soil fertility parameters on major constraints for plant growth and optimal crop production such as water retention capacity, roots development, soils aeration, nutrients availability, nutrients abundance and cations balance. Based on physicochemical soil properties, fertility parameters and Soil Quality Index (SQI), four soil fertility classes were identified in the area: (i) very good fertility soils (66 km2) that corresponds to Dystric Vitric Andosols (Melanic) above 500m asl; (ii) good fertility soils (506 km2), grouping Dystric Vitric Andosols (Melanic) below 500m asl and Leptic Fragic Umbrisols; (iii) fairly good fertile soils (787 km2) including Dystric Fragic Cambisols (Humic), Rhodic Acrisols (Cutanic Humic), Fragic Umbrisols (Arenic), and Mollic Ferralsols (Eutric Humic); (iv) poorly fertile soils (375 km2) including Umbric Andosols (Fragic) and Umbric Pisoplinthic Plinthosols (Haplic Dystric). The principal indicators controlling soil quality in the Tombel area as derived from ANOVA and PCA analyses, are: Ca, Mg, pH water, organic matter (OM), available P, total Nitrogen and CEC. Four of the seven indicators (Ca, pH, OM, P) were also identified as important indicators for assessing the fertility status of the different soils groups in the Tombel area

Pollution des eaux superficielles et des nappes en milieu urbain : cas de la zone industrielle de Douala-Bassa (Cameroun)

Une étude a été menée dans la zone industrielle de Douala-Bassa afin d'évaluer l'ampleur de la pollution des cours d'eau et des nappes superficielles et de prédire la vulnérabilité de ces dernières. L'étude est basée sur l'analyse des eaux issues de deux campagnes de terrain portant chacune sur 7 prélèvements dans les eaux de surface et 8 dans les eaux souterraines. Outre les analyses physico-chimiques de base, la particularité de l'étude a porté sur la caractérisation de la matière organique et la dynamique de métaux lourds, notamment le plomb, lenickel et le cuivre. Les résultats montrent que les eaux de surface sont neutres (pH 6,2), peu minéralisées (conductivité moyenne 262 mS/cm) et peu turbides (7 NTU) à l'amont. Elles s'enrichissent ensuite dans leréseau où elles deviennent acides (pH 5,8), plus minéralisées (623 à 818 mS/cm) suite aux apports générés par les activités industrielles et domestiques. Les eaux de surface sont polluées (carbonique organique total, 13,0 mg/l ; turbidité 168 NTU). Une source potentielle de pollution au nickel et en matière organique est observée dans les eaux souterraines qui compromet l'exploitation durable de cette ressource en eau

Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity

Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)

Differentiated Neogene bauxitization of volcanic rocks (western Cameroon): morpho-geological constraints on chemical erosion

Published online: 30 May 2020Lateritic weathering of Miocene volcanic rocks from western Cameroon highlands formed duricrusted bauxitic profiles. Two weathering profiles on ca. 14 Ma basalt and ca. 16 Ma trachyte were studied using geochemical mass balance functions. Less mobile elements Ti and Zr were used as references to quantify volumetric change (strain, ε), element transfer rate (τ) and geochemical mass transfers during the bauxitization process of basalt and trachyte. Conversion of parent rocks to kaolinite and goethite rich saprolites evolved to Al-Fe rich bauxites, mostly composed of gibbsite and iron oxy-hydroxides (goethite and hematite). However, formation of Al-Fe bauxitic profiles required higher Si leaching on trachyte than on basalt. Our results document that chemical weathering of a larger thickness of trachyte than basalt has been required to form a unit meter of weathering profile, implying differential rates of rock chemical erosion and topographic decay of landscapes. Rates of chemical erosion and formation of lateritic weathering profiles in western Cameroon have been mostly controlled by drainage conditions and volcanic rocks composition (mostly SiO2 content differences), that also resulted in contrasted landscapes evolution during the Neogene

Granulometric Evolution of Soils in Response to Their Fertilization with Crushed Rocks: Case Study of the Western Highlands Andosols Treated with Trachyte Powder

The present paper aims to highlight the consequence of the fertilization of soils with rock powder on their granulometric evolution. For that purpose, Andosols developed on trachyte in the upper part of the southern limb of the Bambouto Mountains were fertilized with trachyte powder at different rates, activated with water and incubated during nine months. The different treatments generate the granulometric evolution of soils. The increasing of the amounts of trachyte powder as same as the duration of the incubation process makes the evolution more significant. In the detail, that treatment induces the enrichment of the treated soils in silts particles in the expense of clay and sands. At the end of the process, soils with high amounts of sands and silts in general are engendered. The use of rock powder as fertilizers must be gainfully preceded by the acquisition of informations concerning their amounts in organic matters. In case of low amounts, a supply with organic fertilizers would be necessary.</jats:p

Impact of the Mixture of Water from Cooked Bean and Human Urine on the Growth of Some Common Plants in Cameroon: Case Study of Talinum fruticosum L. and Ocimum gratissimum L.

The sustainable improvement of plant nutrition can provide sufficient food for all and can keep the environment clean. In that point of view, the present study aims to provide to farmers some contextualized and efficient fertilizers. In the present work, 161 plants of Talinum fruticosum L. and 161 plants of Ocimum gratissimum L. were regularly treated with a mixture of human urine and water from cooked beans (Phaseolus vulgaris) in a 1:1 ratio during three months. 161 of each of these plants were used as control. The experimental design was a randomized complete block in 4 replicates. The size of the studied parts of the targeted plants was highly enhanced in three months in response to the use of the mixture. The leaves of Ocimum gratissimum L. treated shew an average of 22 cm of length and 7.7 cm of width while those of the control shew an average length of 8 cm and 4.8 cm of width. Concerning the leaves of Talinum fruticosum L. treated, they measured 10.1 cm of length and 4 cm of width in average and those of the control 4.1 cm of length and 2 cm of width in average. Peasants could thus save a lot of money by using their excreta and some of their sewages as fertilizers to promote the sustainable development of their ecosystems. Further lab analysis on water from cooked beans alone and on the mixture made of human urine and water from cooked beans could ease in the future the acquirement of new knowledge about them. The consequence of that improvement will simply be the capitalization of those fluids as source of easily absorbable nutrients for plants nutrition.</jats:p

Organisation of Soils along the Sides of Interfluves in the Western Highlands of Cameroon: Case Study of an Andosolic Toposequence on Trachyte in the Upper Part of the Southern Limb of Bambouto Mountains

The acquisition of knowledge on soils tells how to use them sustainably. So, the organization of soils along the sides of interfluves in the western highlands of Cameroon was put into relief in order to understand their genesis, organization, and evolution. Field work and lab analysis helped to reach the focuses. These soils are thin, highly differentiated, with many local specificities. Their organization and their thickness vary from up to downhill. Vertically, they include: An isalteritic horizon; a yellow vague polyhedral horizon; a red distinct polyhedral horizon; a discontinuous breastplate with two facies; a porous vague crumby dark reddish brown horizon; and a strongly dark grey, porous, thixotropic and crumby superficial horizon. The pedon/alterite ratio is about 2/1, and the hardened level/alterite ratio is 1/4. The alteritic level represents about 1/3 of the whole soil profile. Microscopically, these soils lack plasmic separations. Plasmas are respectively isotic in the dark reddish brown and strongly dark grey horizons, clayey asepic in the yellow and red polyhedral horizons, cristic in the isalteritic horizon, cristic and locally isotic in the discontinuous breastplate. Gibbsite, halloysite, kaolinite and allophane are the main minerals; goethite, quartz, hematite and rutile are also present. Geochemically, aluminum is the main chemical component in the deepest horizons, while in those at the top of the soil profile, silicon and aluminum has quite similar concentrations. Others specificities include their low bulk density (0.6 to 0.9 gcm-3), the abundance of clayey particles at the bottom of the soil profile, sand and silt at its summit. Ferrallitic and andosolic characteristics coexist in the studied soils. This ambivalence makes them to be simply «andic ferallitic, desaturated, humic and strongly rejuvenated soils».</jats:p

Water from Cooked Beans as Substrate for Some Heterotrophic Organisms: Case Study of Moulds

The discovery of new ecological fertilizers can sustainably enhance plants nutrition. In that point of view, the present study aimed to demonstrate the high concentration of water from cooked beans in organic compounds, various mineral salts and water. For that purpose, moulds were used because of the above listed elements as their basic feeding needs. Cold water from cooked beans was collected and kept during five days at open-air; the evolution of its aspect was daily followed up. The experimental design was a randomized complete block in 10 replicates; an eleventh bucket filled with the same water was used to perform some of its characterization. The moulds are Aspergillus L. The water from cooked beans is a heterogeneous mixture and particularly a globular proteic suspension. At rest, it organizes itself in a superficial flaky domain and a lower liquid domain. The flaky domain is mainly organic and the liquid domain is mainly both mineral and aqueous. The density of the flaky domain was 0.964 and that of the aqueous domain was1.011. The average speed of the growth of Aspergillus L. at the surface of the water from cooked beans was 3,17 cm2/H; they cover then in five days a surface of 379.74 cm2. The exponential growth of Aspergillus L. at the surface of the water from cooked beans generated a continuous decreasing of the pH; this behavior shows that the water from cooked beans seems to be an adequate substrate; it then implicitly contains all the nutrients required for their optimal development; this include water, organic matters and mineral salts among which nitrogen, potassium, phosphorus, sulfur and calcium can be named; it is then a complete liquid organic fertilizer. That water appears also as a high grade activator for soils micro flora. Peasants could thus save a lot of money by using this liquid single or in combination with other fertilizers to promote the sustainable development of agriculture in their ecosystems.</jats:p