Food security issues continue to be a challenge in most parts of the globe, especially in sub-Saharan Africa (SSA). Several research attempts on addressing this issue have mainly been on nutrient replenishment using combined nutrient application of organic amendments and mineral fertilizer inputs. However, there is limited information available on the potential mechanisms underlying nutrient interactions associated with co-application of organic amendments and mineral fertilizers. Therefore, this review focuses on the mechanisms underlying crop nutrient interactions, with particular emphasis on improved nutrient synchrony, priming effect, general soil fertility improvement and balanced proportion of nutrients required by crops. Following a brief overview of the mechanisms, the review describes four common pre-determined nutrient ratios required by plants depending on its life cycle, environment and genotypic characteristics in order to attain the crop’s maximum genetic potential. The review concludes with the need for future research to understudy mechanisms causing nutrient interaction under cropping systems, so as to apply nutrients at the most appropriate time to synchronize nutrient release with crop uptake, with the utmost goal of promoting sustainable crop production and enhancing food security.

Low inherent nitrogen (N), phosphorus (P), and potassium (K) contents of smallholder farms limit maize grain yield. Maize grain yield response to N, P, and K mineral fertilizer application and economically optimal rates for nitrogen (EOR^N), phosphorus (EOR^P), and potassium (EOR^K) were evaluated on a Ferric Acrisol within the semi-deciduous forest zone of Ghana. The nutrient rates evaluated were N (0, 30, 60, 90, and 120 kg N ha⁻¹), P (0, 30, 60, and 90 kg ha⁻¹ P₂O₅), and K (0, 30, 60 and 90 kg ha⁻¹ K₂O). The treatments were arranged in a randomized complete block with three replications using an incomplete factorial design. Nutrient responses were determined using asymptotic quadratic-plus plateau functions. The best nitrogen rate for all P and K levels was 60 kg ha⁻¹, which gave grain yield of 5 t ha⁻¹. Nitrogen uptake, N agronomic and N recovery efficiencies peaked at 60 kg N ha⁻¹ while N partial factor productivity declined with increasing N application rate. Cost to grain price ratios (CP) were 1.29, 1.65, and 1.65 for N, P, and K, respectively. The EOR^N was 61 kg ha⁻¹, 32% less than the recommended 90 kg N ha⁻¹ for maize production in the semi-deciduous forest zone of Ghana. Nitrogen application had the lowest CP ratio, making its application economically profitable than P and K. The findings suggest that the application of N at 61 kg N ha⁻¹ to maize is economically profitable than at higher application rates. However, further studies should be conducted on farmers’ fields to validate the results obtained.

Mechanisms underlying interactive effects of nutrient inputs on crop yields are poorly understood especially throughout sub-Saharan Africa. This research thus sought to evaluate the possible mechanisms causing the interaction effects from compost and mineral fertilizer and quantify the relative contribution(s) of the mechanisms to added benefits in grain yield. The research involved a 3-year field experiment followed by a greenhouse incubation study. Both field and incubation experiments were 5 × 5 factorial arranged in Randomized Complete Block Design and Completely Randomized Design (CRD) with three replications, respectively. The factors considered were five levels of mineral fertilizer (0, 25, 50, 75, and 100% of 90:60:70 kg ha⁻¹ N:P₂O₅:K₂O) and compost (0, 25, 50, 75, and 100% of 5 Mg ha⁻¹ compost). The mechanisms evaluated were nutrient synchrony, priming, general soil fertility improvement (GFI), and balanced ratio of nutrients. The conjoint application of compost and mineral fertilizer significantly (p ≤ 0.05) influenced grain yields of maize, with 50%_RRMF + 100%_RRCo producing the highest average grain yields in 2015 and 2017 with relative average grain yield increases of 167 and 98% over the control (no application), respectively. The conjoint application of nutrients resulted in synergistic and antagonistic interactions. Synergistic interactions were observed in the first 2 years of the study, followed by antagonistic interactions in the third year. Three principal components cumulatively explained 86% of the variation among the mechanisms. The mechanisms which contributed most to the added benefits were priming effect, balanced nutrient ratio, and nutrient synchrony.

Rice production in Ghana is limited by low varietal choices, which puts farmers at a disadvantage in meeting the market demand for consumers. The objectives of this study were to (i) assess the yield potentials of improved rice varieties developed by the Africa Rice Center (AfricaRice), and (ii) to allow farmers to select improved varieties of their choice based on growth and yield, as observed in the field, in order to ensure a high adoption rate, increase productivity and food security. Two seasons (i.e. 2020 major and 2020–2021 minor) field experiments were conducted at two lowland within the Mankran watershed in the Ashanti region of Ghana. The experiment comprised thirteen (13) improved varieties and two local checks and was conducted using recommended good agronomic practices. The key findings of the study showed that growth and yield parameters vary significantly between varieties across locations. The biplot analysis showed that varieties FARO 66, SAHEL 317, and Amankwatia are the best in the major season while WITA 9, GT 11, ARS-957-BGJ-171-15-D-B, NERICA L36, and AGRA were the best in the minor season at both locations. Farmers’ preference for the varieties was based not only on growth and yield but on resistance to lodging, pests, and diseases. In conclusion, the best performing varieties have demonstrated yield potential which is about 92% higher than the yield of the local checks and can be recommended for adoption by farmers. Future breeding programs on these varieties should include the most preferred attributes by farmers in this study. GRAPHICAL ABSTRACT

Highly vulnerable to climate change. With the average temperature risen by 1.2℃ since precolonial times, exceeding the global average, the effects of climate change pose and thereby posing a challenge in feeding the ever-increasing projected 8.6 billion human population by 2030 (UN DESA, 2021). In recent times, several agriculture and soil management practices such as agricultural residue burning, application of mineral fertilizers and crop residues to the soil, the use of nitrogen-fixing crops in soil management, production of paddy rice, tillage practices, land use change, and other anthropogenic factors have contributed to greenhouse gas (GHG) emissions, a major contributing factor to climate change. These have seriously resulted in suboptimal crop yields and consequently hunger, malnutrition and food insecurity.Climate change is thus, a threat to sustainable crop production and food security. While global discourses often emphasize climate adaptation, there is a growing recognition that mitigation strategies; those that reduce or sequester GHGs must be integrated into agricultural planning to achieve long-term sustainability. Furthermore, as envisioned by the United Nation's Agenda 2030 to achieve a better and more sustainable future for all people and the world by 2030, strategies adapted to mitigating climate change effects on sustainable crop production is thus necessary for achieving the sustainable development goals (SDG) 1 and 2 with the outcome target of ending hunger and improving access to food; achieving food security and improved nutrition; promoting sustainable agriculture and resilient agricultural practices in SSA. This Research Topic on explores climate change mitigation strategies as reflected across six recent studies from Ethiopia, Nigeria, Tanzania, and broader African agro-ecosystems.Drawing on empirical field trials from these countries, as well as thematic reviews, the studies explore the integration of conservation agriculture (CA), underutilized legumes, biofertilizers, and intercropping strategies. For years, the dominant discourse in African agricultural research has focused on climate change adaptation. However, mitigation is no longer optional. Agriculture contributes approximately 20% of total GHG emissions globally (Ahmed et al., 2020), and SSA's share is rising due to deforestation, livestock, and fertilizer overuse. Therefore, these studies together present a roadmap for low-cost, ecologically sound, and scalable mitigation solutions that directly support sustainable crop production.The studies reviewed under this Research Topic position African agriculture not only as a climate victim but also as a climate solution. Hailu and Teka present a thematic review of CA, highlighting how integrating mitigation into farming systems through carbon sinks, reduced tillage, and biodiversity can reduce emissions while boosting productivity. Among the most promising mitigation strategies is conservation agriculture, contributing to climate change mitigation via carbon sequestration and enhanced soil organic carbon. However, the authors argue that CA adoption remains low due to lack of mechanization, competing crop residue uses, and limited awareness. Scaling CA, thus, requires mechanization subsidies, stakeholder training, and subsidies for CA-compatible inputs. Replacing chemical fertilizers with organic and biological options is another key strategy. Marzouk et al. showed that the optimal combination of Azolla + rice straw + 50% synthetic N in Tanzanian rice paddies outperformed 100% N fertilizer treatments in terms of increased yields (5.3 t/ha) and nitrogen recovery efficiency (163%), while reducing GHG emissions, and improving soil organic carbon and pH levels. The study thus, calls for biofertilizer-based nutrient management to meet the dual goals of sustainability and productivity.In a review by Ayilara et al. , the authors explored how neglected and underutilized legumes like Bambara groundnut, velvet bean, and winged bean offer both nutritional benefits and ecosystem services. They emphasized on how their incorporation into intercropping systems enhances biodiversity, reduces emissions per unit of production, and improves soil quality. Yet, these indigenous species are often excluded from mainstream seed systems and research agenda.The study thus, presents a strong case for mainstreaming indigenous legumes in food security and soil rehabilitation programs. Also, in a follow-up field study by the same authors Ayilara et al., they demonstrated how intercropping legumes with maize revitalized degraded soils and boosted crop nutritional profiles via microbial activity. Biological interactions were found to increase soil organic matter, contributing to mitigation through natural ecosystem restoration. Methodologically, they employ a mix of reviews, field trials with focus-group discussions, mixed methods approach, and trend analysis under different agricultural systems in SSA. The six studies reviewed demonstrate that climate mitigation in African agriculture is multi-faceted in nature, as it is both feasible and transformative. For policy makers, these findings represent scalable and context-responsive solutions that can reduce GHG emissions, enhance soil health, and improving farmer livelihoods, highlighting the need to integrate agroecological and climate-smart practices into national agricultural strategies. Integrating CA, biofertilizers, indigenous crops, and farmercentered CSA offers a practical roadmap toward resilient, productive, and low-emission farming systems. Future research must therefore build upon these insights through long-term, multilocation trials that assess environmental tradeoffs of different climate mitigation pathways, taking into consideration their financial implications as well.