Significance: The world has been struggling to find sustainable ways to increase crop production to satisfy the needs for food, feed, fiber, and industrial uses while reducing negative environmental impacts. This challenge is magnified in countries/regions where the availability of farmable land for agriculture is limited. We developed an integrated cropping system that incorporates key farming tactics. Tested in 16 field experiments over 12 consecutive years (2006 to 2017), the integrated system increased crop yields while decreasing the environmental footprint. The integration enables significant synergies in biophysical processes to occur under a wide range of crop inputs, suggesting that system integration can be adopted globally for a range of smallholder farming.

This study investigated the influence of biosolid applications on soil carbon storage and evaluated nutrient management strategies affecting soil carbon dynamics. The research assessed alterations in soil pH, soil carbon stock, and soil nitrogen content within short-term and long-term biosolids-amended soils in Bible Hill, Nova Scotia, Canada, extending to a depth of 0-60 cm. The findings indicated an increase in soil pH with alkaline treatment biosolids (ATB) applications across both study sites, with a legacy effect on soil pH noted in the long-term biosolids-amended soil following a single ATB application over 13 years. Both sites demonstrated significant increases in soil total carbon (STC) and soil organic carbon (SOC) within the 0-30 cm soil depth after biosolid application, and soil inorganic carbon (SIC) accounted for approximately 5-10% of STC, specifically in the surface soil layer (0-15 cm). In the long-term study site, annual 14, 28 and 42 Mg ATB ha^-1 treatments resulted in a substantial rise in soil carbon stock (59.5, 60.1 and 68.0 Mg C ha^-1), marking a 25% increase compared to control soil. The SOC content in biosolids-amended soil showed a declining trend with increasing soil depth at both study sites. Notably, the carbon stock in the short-term site was observed in composted biosolids (COMP) > ATB > liquid mesophilic anaerobically digested biosolids (LMAD) from the 0-60 cm soil depth. Approximately 79-80% of the variation in SOC response at both sites was concentrated within the top 30 cm soil. Soil total nitrogen (STN) showed no significant differences at the short-term site, and STN in biosolids-amended soil decreased with increasing soil depth at the long-term site. Biosolids-induced C retention coefficients (BCR) for ATB remained consistent at both sites, ranging from -13% to 31.4% with a mean of 11.12%. BCR values for COMP ranged from 1.9% to 34.4% with a mean of 18.73%, while those for LMAD exhibited variability, spanning from -6.2% to 106.3% with a mean of 53.9%.

Canada has a quarter of the world's peatlands accounting for an estimated 150 Gt of stored carbon. While over 98% of Canadian peatlands are intact, agriculture has been estimated as accounting for the greatest peatland disturbance by area. Greenhouse gas (GHG) emissions from peatland agriculture can contribute a large proportion of national anthropogenic emissions for some countries. In Canada, estimates of GHG emissions from cultivated peat soils are incomplete. Improved accounting of these GHG emissions is required to inform decisions about where to deploy ecological restoration projects and where to allow future agricultural expansion as climate warms. Compiled studies that measured GHG fluxes from agricultural peat fields in Canada resulted in mean emissions factors of 5.1 t CO₂e ha⁻¹ year⁻¹, −0.12 kg CH₄ ha⁻¹ year⁻¹, and 14.3 kg N₂O‐N ha⁻¹ year⁻¹ for carbon dioxide, methane, and nitrous oxide, respectively. Combining these values with a compilation of estimates of agricultural peatland disturbance area in Canada, GHG emissions estimates in Canada arising from peatland converted to agriculture remain highly uncertain, ranging from 1.4 to 35 Mt CO₂e year⁻¹, with a median value near 18 Mt CO₂e year⁻¹. The largest contributor to this wide range of estimates is uncertainty peatland area affected, indicating an urgent need to improving mapping of organic soils under agriculture in Canada. To help guide decision‐making in Canada, we recommend a network of research stations across a range of agricultural management intensities and climate regions for monitoring hydrological conditions and GHG exchange on organic soils affected by agriculture.