Among 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.

Banded iron formations (BIFs) are the most significant source of iron in the world. In this study, we report petrographic and geochemical data of the BIF from the Meyomessi area in the Ntem Complex, southern Cameroon, and discuss their genesis and the iron enrichment process. Field investigations and petrography have revealed that the studied BIF samples are hard; compact; weakly weathered; and composed of magnetite, subordinate quartz, and geothite. The geochemical composition of the whole rock reveals that iron and silica represent more than 98 wt% of the average composition, whereas Al₂O₃, TiO₂, and high‐field strength elements (HFSE) contents are very low, similar to detritus‐free marine chemical precipitates. The total iron (TFe) contents range from 48.71 to 65.32 wt % (average of 53.29 wt %) and, together with the low concentrations of deleterious elements (0.19 wt % P on average), are consistent with medium‐grade iron ores by global standards. This interpretation is confirmed by the SiO₂/Fe₂O_3total versus (MgO + CaO + MnO)/Fe₂O_3total discrimination plot in which most of the Meyomessi BIF samples fall in the field of medium‐grade siliceous ore. Only one sample (MGT94) plots in the high‐grade magnetite–geothite ore domain. The high Fe/Ti (376.36), Fe/Al (99.90), and Si/Al (29.26) ratios of the sample are consistent with significant hydrothermal components. The rare earth elements (REE) contents of the studied BIF samples are very low (∑REE: 0.81–1.47 ppm), and the Post‐Archaean Australian Shale (PAAS)‐normalized patterns display weak positive Eu anomalies (Eu/Eu*: 1.15–1.33), suggesting a syngenetic low‐temperature hydrothermal solutions, similar to other BIF worldwide. However, the Meyomessi BIFs show high Fe contents when compared to the other BIFs. This indicates an epigenetic mineralization process affected the Meyomessi BIF. From the above results and based on the field and analytical data, we propose that the genetic model of iron ores at the Meyomessi area involves two stages of the enrichment process, hypogene enrichment of BIF protore by metamorphic and magmatic fluids followed by supergene alteration as indicated by the presence of goethite in the rocks.

The impact of direct-seeding mulch-based cropping systems (DMC), direct seeding (DS) and tillage seeding (TS) on Sorghum yields, soil fertility and the rehabilitation of degraded soils was evaluated in northern Cameroon. Field work consisted of visual examination, soil sampling, yield and rainfall data collection. Three fertilization rates (F1: 100 kg ha−1 NPK + 25 kg ha−1 of urea in DMC, F2: 200 kg ha−1 NPK + 50 kg ha−1 of urea in DMC and F3: 300 kg ha−1 NPK + 100 kg ha−1 of urea in DMC) were applied to each cropping system (DS, TS and DMC), resulting in nine experimental plots. Two types of chemical fertilizer were used (NPK 22.10.15 and urea) and applied each year from 2002 to 2012. Average Sorghum yields were 1239, 863 and 960 kg ha−1 in DMC, DS and TS, respectively, at F1, 1658, 1139 and 1192 kg ha−1 in DMC, DS and TS, respectively, at F2, and 2270, 2138 and 1780 kg ha−1 in DMC, DS and TS, respectively, at F3. pH values were 5.2–5.7 under DMC, 4.9–5.3 under DS and TS and 5.6 in the control sample. High values of cation exchange capacity were recorded in the control sample, TS system and F1 of DMC. Base saturation rates, total nitrogen and organic matter contents were higher in the control sample and DMC than in the other systems. All studied soils were permanently not suitable for Sorghum due to the high percentage of nodules. F1 and F2 of the DS were currently not suitable, while F1 and F3 of DMC, F3 of DS and F1, F2 and F3 of TS were marginally suitable for Sorghum due to low pH values.