This study was set up to compare the inoculation of Bradyrhizobium japonicum strains and the application of nitrogen (N) fertilizers (urea with 46% nitrogen) on the growth and yield of Bambara groundnut accessions. The study results suggest that the benefits of Bradyrhizobium japonicum (B. japonicum) strain inoculation are greater and that the strain could reduce reliance and the excess amount spent by farmers to procure inorganic fertilizers and avoid the negative effect of N fertilizer on the environment after its use. Field studies were conducted in two different geographical locations, in Ibadan (Ib) and Ikenne (Ik), Nigeria, during the rainy season between August and December in 2019 and 2020. The experiment was arranged in a randomized complete block design (RCBD) in both locations and seasons and was replicated three times, with each block representing each replicate. It had a 10 × 6 factorial arrangement with one block holding the 10 accessions of Bambara groundnut inoculated with four B. japonicum strains. The second block had N fertilizer application and the third control block was without inoculation or fertilizer application. The 10 accessions of Bambara groundnut used in the study were as follows: TVSu-378, TVSu-506, TVSu-787, TVSu-1606, TVSu-1698, TVSu-1739, TVSu-710, TVSu-365, TVSu-475, and TVSu-305. Six seeds of each accession were coated with each of the four B. japonicum strains, namely, FA3, USDA110, IRJ2180A, and RACA6, before planting them in the field in both locations during the rainy season. In the next block, urea as N fertilizer (46% nitrogen) was applied to the uninoculated seedlings of accessions of Bambara groundnut 2 weeks after planting (WAP). The third block was the control with zero inoculation and zero fertilizer application. Data collected were subjected to an analysis of variance and mean and were separated using Duncan's Multiple Range Test (DMRT) at a p > 0.05 level of probability. It was found that FA3 inoculation significantly enhanced the growth traits of the accessions than other strains and N fertilizer application. In both locations and seasons, at 7 weeks after planting (WAP) and 12 WAP, plant height (19.54 and 22.71 cm), number of branches (33.63 and 62.77), number of leaves (116.54 and 209.25), terminal leaf length (5.62 and 6.00 cm), and width (2.09 and 2.56 cm) were recorded. The yield and yield components recorded at harvest were as follows: pod length (13.27 cm), pod width (9.08 mm), seed length (9.39 mm), seed width (6.92 mm), weight of 100 seeds (56.85 g), and yield/ha (750.72 kg). The yield and yield components were also significantly influenced by the inoculation of FA3 and RACA6 than other inoculated strains and N fertilizer application in both locations and seasons.

Compost is an inexpensive agricultural waste which improves soil health and quality. The experiment was carried out to assess the influence of compost and mycorrhizal inoculation (Glomus mosseae) on soil properties and growth of yellow bell pepper in pots under screen house conditions, in a completely randomized design with three replicates. The treatments included mycorrhizal inoculation only (C0M1), compost at 20 t ha-1 only (C1M0), compost at 30 t ha-1 only (C2M0), compost and mycorrhizal inoculation at 20 t ha-1 (C1M1), compost and mycorrhizal inoculation at 30 t ha-1 (C2M1) and control (no amendment / uninoculated). Compost and mycorrhizal inoculation (C1M1 and C2M1) significantly improved soil N, P and K compared to control. Inoculation with mycorrhizal only (C0M1) increased uptake of N, P, K, Ca and Mg compared to uninoculated. Co-utilization of compost and mycorrhizal inoculation significantly increased root and shoot dry biomass compared to uninoculated. The highest fruit yield was obtained at C2M1 followed by C1M1 in comparison to compost application only. Treatment C2M1 recorded the highest prevalence of percent root colonization. This suggests that compost and Glomus mossea could be considered to have a sustainable potential for better growth and yield performance in the production of yellow bell pepper in an Alfisol.

Field experiments were conducted in two different agroecological locations of Ibadan and Ikenne in Nigeria from August through December during the 2019 and 2020 cropping seasons. The studies were set up to reduce reliance on inorganic nitrogen fertilizer and to embrace the use of nitrogen-fixing bacteria to improve legume production to increase farmers' output and profitability. Ten accessions of the Bambara groundnut (BGN) were used in the trials. Seeds of each BGN accession were coated with each of the following Bradyrhizobium japonicum strains (B. japonicum): FA3, RACA6, USDA110, and IRJ2180A before planting. Furthermore, Nitrogen (N) fertilizer (20 kg/ha, urea) was applied to seedlings without inoculation, and uninoculated seedlings (without inoculation and without fertilization) served as control. The experiment was, therefore, a factorial arrangement (10 BGN accessions, 4 B. japonicum strains, N fertilizer application, and an uninoculated control). The yield and yield components of the inoculated BGN accessions were significantly enhanced at both agroecological locations and seasons. Among the B. japonicum strains used for inoculation, RACA6 strains significantly enhanced the yield and yield component of TVSu-1698 than other inoculated BGN accessions with a mean value of 6,234 ± 87 kg ha−1 recorded in both locations and seasons, compared to the result obtained in the combination of TVSu-1698 with N fertilizer with a mean value of 3,264 ± 943 kg ha−1. By using TVSu-1698 with RACA6 strain, farmers can get 85% more yield than on average with other genotypes/strains combination, while an average yield of 60% could be obtained by farmers using N fertilizer application.

Striga species are obligate parasitic weeds most of which are members of the Orobanchaceae family. They are commonly associated with staple crops and constitute threats to food security, especially in Sub-Saharan Africa. They pose deleterious impacts on staple cereal crops like maize and pearl millet, resulting in 7–10 billion dollars yield losses or, in extreme infestations, entire crop losses. Farmers' limited knowledge about the weed (genetics, ecology, nature of the damage caused, complex life cycle, interactions with its host and associated microbes) and their attitude toward its control have negatively affected its management and sustainability. With the present Striga management such as mechanical, chemicals, cultural and biological measures, it is extremely difficult to achieve its active management due to nature of the association between host plants and parasites, which requires highly selective herbicides. The use of soil microbes has not been well explored in the management of Striga infection in African countries. However, many soil microorganisms have been considered viable biological control techniques for fighting parasitic weeds, due to their vast action and roles they play in the early stage of host-Striga interaction. Their application for pest control is well perceived to be cost-effective and eco-friendly. In this review, we gave a comprehensive overview of major knowledge gaps and challenges of smallholders in Striga management and highlighted major potentials of microbial-based approach with respect to the mechanisms of host-Striga-microbe interactions, and the metagenomics roles on Striga management that include understanding the microbe and microbial systems of Striga-infested soil.