Soils are critical to the carbon cycle, sequestering atmospheric carbon and facilitating carbon fixation and stabilization through plant and microbial activity (Trivedi et al., 2013). However, the agricultural sector is also a significant source of greenhouse gas (GHG) emissions, with CO₂, CH₄, and N₂O contributing substantially to climate change. Emissions are primarily as CO₂ (98%) with smaller but highly impactful contributions from N₂O (1.98%), which has 265 times the global warming potential of CO₂  (Fuentes-Ponce et al., 2022; Iqbal et al., 2023).

Modern agriculture has increased crop yield significantly (Knapp and van der Heijden, 2018). To meet the demands of a growing population, intensive agricultural practices have been used to increase crop yields (Boone et al., 2019; Knapp and van der Heijden, 2018). Since the 1970s, however, over-exploitation of soils with conventional agriculture has been considered a non-sustainable management practice due to increased soil degradation (Sumberg and Giller, 2022; Pereira et al., 2020). Despite the production needs being met by conventional farming, sustainable agriculture has the potential to produce a high crop yield while also being environmentally sustainable (Seufert et al., 2012).

Nitrogen and phosphorus nutrients boost plant growth (Brady and Weil, 2010). The input of inorganic nitrogen fertilizer reduces essential nutrients in plants after a long term (Shiwakoti et al., 2019). Attention should be taken to efficiently use nitrogen fertilizers, enabling crop production with less use of chemicals (Balmford et al., 2018; Tilman et al., 2011). 

Organic soil amendments can help mitigate the environmental impacts of intensive farming. Adding carbon to soil benefits microbial communities and supports plant growth. Carbon primarily enters soils through plant-derived organic matter (OM), such as shoots, roots, litter, and microbial necromass (Gross and Harrison, 2019). Compost introduces fresh OM into the soil, enhancing fertility and structure, while biochar reduces greenhouse gas emissions by stabilizing carbon (Iqbal et al., 2023). Properly managed biochar and compost are promising amendments for reducing GHG emissions and improving soil health, though their effects on CO₂ and N₂O emissions depend on composition and application methods (Shaaban et al., 2018; Jiang et al., 2011; Han et al., 2023).

Compost is a product of the aerobic decomposition of organic materials, such as manure and food waste (Jiang et al., 2011; Sadaka and El–Taweel, 2003) and can be used as a rich organic fertilizer. For a good quality composting, proper aeration, moisture, and C/N ratio are important to ensure the process remains aerobic, and to create an environment that promotes microbial activity (Geisseler et al., 2021; Sadaka and El–Taweel, 2003). The benefit of adding compost as an agricultural soil amendment is to improve SOC, thus increasing carbon sequestration (Chen et al., 2023).

Biochar, a carbon-rich product of biomass pyrolysis, can be produced from materials such as wood, crop residues, and manure, with wood yielding the highest carbon content (El-Naggar et al., 2019; Shaaban et al., 2018). It has the benefit of increasing stable SOC, soil water retention, and soil fertility (Zhang et al., 2022; El-Naggar et al., 2019; Liu et al., 2016). Regarding greenhouse gas emissions, biochar has the potential to reduce N₂O emissions by improving soil aeration and adsorbing nitrogen compounds (Cayuela et al., 2014). On a short-term, biochar may increase CO2 emissions due to priming effect, which happens because the increase in carbon stimulates microbial activity. On a long-term though, studies show that N2O and CO2 emissions can be reduced significantly (Wang et al., 2021).

Wood ash and gypsum are soil amendments that focus on enhancing soil health thus can only indirectly mitigate GHG emissions. Wood ash, a byproduct of biomass combustion, is rich in calcium, potassium, and trace minerals, making it an effective liming agent to reduce soil acidity and improve nutrient availability (Demeyer et al., 2001). Gypsum, composed of calcium sulfate, improves soil structure by reducing compaction and improves sodicity, replacing sodium in the soil with calcium to enhance fertility (Chen and Dick, 2011).