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The persistence of inoculants from year to year in soybean [Glycine max (L.) Merr.] cultivation and the residual benefits in soybean production are pertinent to adopting such practices in sub-Saharan Africa countries such as Ghana. A study was conducted to determine the residual effect of commercial rhizobium inoculants on soybean and selected soil health parameters after three cropping seasons. The experimental design was a split-plot. The main plot consisted of three soybean cultivars (Jenguma, Afayak, and Songda), and the subplot comprised of three peat-based commercial bradyrhizobium inoculants (Biofix, Legumefix, and NoduMax) and an uninoculated control. Assessments were made on nodulation, shoot dry matter (DM), grain yield, grain total N uptake, permanganate-oxidizable carbon (POXC), soil pH, and potentially mineralizable C. Among the soybean cultivars, Afayak produced greater nodule mass on the lateral root and the whole root system compared with the other cultivars. Jenguma and Afayak yielded greater shoot DM relative to Songda. Regarding the inoculants, Biofix increased nodule mass on the lateral root and the whole root system compared with the control. Biofix and NoduMax produced superior grain yield relative to the control. Biofix also produced greater grain yield than Legumefix. A superior pod harvest index and an improved grain total N uptake were produced by Biofix compared with Legumefix and the control. Commercial inoculants enhanced POXC availability at harvest, whereas potentially mineralizable C declined with inoculation treatments.Commercial inoculants (Biofix and NoduMax) enhanced nodulation, grain yield, and selected soil health indicators 3 yr after inoculation.

Changes in land cover (LC) can lead to environmental challenges, but few studies have investigated LC changes at a country wide scale in Ghana. Tracking LC changes at such a scale overtime is relevant for devising solutions to emerging issues. This study examined LC changes in Ghana for the past almost two and half decades covering 1995–2019 to highlight significant changes and opportunities for sustainable development. The study used land cover data for six selected years (1995, 2000, 2005, 2010, 2015, and 2019) obtained from the European Space Agency. The data was analyzed using R, ArcGIS Pro and Microsoft Excel 365 ProPlus. The original data was reclassified into eight LC categories, namely: agriculture, bare area, built-up, forest, grassland, other vegetation, waterbody, and wetland. On average, the results revealed 0.7%, 131.7%, 23.3%, 46.9%, and 11.2% increases for agriculture, built-up, forest, waterbody, and wetland, respectively, across the nation. However, losses were observed for bare area (92.8%), grassland (51.1%), and other vegetation (41%) LCs overall. Notably, agricultural land use increased up to 2015 and decreased subsequently but this did not affect production of the major staple foods. These findings reveal the importance of LC monitoring and the need for strategic efforts to address the causes of undesirable change.

Background and aim : Soybean seeds inoculation with effective rhizobia (Rh) strains and phosphorus (P) application are agricultural best practices that enhance grain yield. However, in Northern Ghana, where these practices are progressively under adoption, unpredictable yield, and poor understanding of factors of yield variation often limit its potential. We assessed the influencing factors to soybean yield variability from biophysical and managed input variables (Rh inoculants, P rates, and sources). Methods On-station and on-farm soybean plots were inoculated with three Rh inoculants (Rh1, Rh2, and Rh3), treated with two P rates (0 and 30 kg P ha-1), and two P sources [rock phosphate and Triple superphosphate forms]. Yield data was predicted using the random forest (RF) model, and factors of yield variability were assessed using the linear mixed models and the forward redundancy analysis (rda). Results The yield prediction accuracy was greater for the on-station experiment compared to the on-farm dataset with a trained coefficient of determination (R2) of 0.77 and 0.66, respectively. The top variables of yield prediction were the Rh × P fertilizer, P sources, Rh strains, and exchangeable soil Mg2+ concentrations. The Rh × P treatment increased soybean grain yield by 3.0 and 3.9 folds for the on-farm and on-station trials respectively, compared to the control. Conclusion The RF model and the forward rda unearthed a significant contribution of the soil exchangeable Mg2+ to the yield variation. The mechanisms underlying the role of Mg on soybean growth deserve further research investigations to increase soybean production in Ghana sustainably.

Soybean is rarely inoculated with commercial Bradyrhizobium inoculants in Ghana's cropping systems. A 2-year field study was conducted at Council for Scientific and Industrial Research-Savanna Agricultural Research Institute's experimental field at Nyankpala, Ghana to assess how commercial inoculants affect growth, nodulation, nitrogen fixation, and grain yield of promiscuous nodulating soybean cultivars. The experiment was a split-plot design with the main plot factor as soybean [tropical Glycine max (L.) Merr. crosses (TGX) cultivars]; Jenguma (TGX1448-2E), Afayak (TGX1834-5E), and Songda (TGX 1445-3E). The subplot factor consisted of three commercial Bradyrhizobium japonicum inoculants, namely, Biofix (strain USDA 110), NoduMax (strain USDA 110), and Legumefix (strain 532c) plus uninoculated control. Shoot biomass and nodulation were assessed at vegetative (V8, 8-leaf stage), full bloom (R2), beginning to pod (R3), full pod (R4), and full seed (R6) stages, respectively, and N fixation and grain yield at maturity. Shoot dry matter increased with growth stage and peaked at the R6 stage with significant effect associated with Biofix and NoduMax. Nodulation on the upper root and the whole root also peaked at the R4 stage, with pronounced effects associated with Biofix and Nodu-Max. Enhanced grain yields of up to 30% were achieved with Biofix and NoduMax compared to the uninoculated control in both 2016 and 2017. Regarding the cultivars, shoot biomass increased with growth stage and peaked at R6 stage and Afayak yielded greater shoot biomass. On average (2 years), Afayak produced greater grain yields than Jenguma and Songda. In conclusion, Biofix and NoduMax were the most promising commercial inoculants for soybean production in Northern Ghana.