This study aimed to investigate the characteristics of gaseous emission (methane—CH₄, carbon dioxide—CO₂, nitrous oxide—N₂O, nitric oxide—NO, hydrogen sulfide—H₂S and sulfur dioxide—SO₂) and the conservation of carbon (C), nitrogen (N), and sulfur (S) during cattle manure composting under different aeration strategies. Three aeration strategies were set as C60, C100, and I60, representing the different combinations of aeration method (continuous—C or intermittent—I) and aeration rate (60 or 100 L·min⁻¹·m⁻³). Results showed that C, N, S mass was reduced by 48.8–53.1%, 29.8–35.9% and 19.6–21.9%, respectively, after the composing process. Among the three strategies, the intermittent aeration treatment I60 obtained the highest N₂O emissions, resulting in the highest N loss and greenhouse gas (GHG) emissions when the GHG emissions from power consumption were not considered. Within two continuous aeration treatments, lower aeration rates in C60 caused lower CO₂, N₂O, NO, and SO₂ emissions but higher CH₄ emissions than those from C100. Meanwhile, C and N losses were also lowest in the C60 treatment. H₂S emission was not detected because of the more alkaline pH of the compost material. Thus, C60 can be recommended for cattle manure composting because of its nutrient conservation and mitigation of major gas and GHG emissions.

The one-time application of blended urea (BU), combining controlled-release urea (CRU) and uncoated urea, has proven to be a promising nitrogen (N) management strategy. However, the long-term sustainability of blending urea remains largely unexplored. To assess whether a single application of blended urea could effectively replace split uncoated urea applications, a long-term field experiment was conducted in the North China Plain (NCP). The results indicated that, when compared to common urea (CU) at the optimal N rate (180 kg N ha⁻¹), BU achieved comparable grain yields, N uptake and NUE (61% vs. 62). BU exhibited a 12% higher 0–20 cm soil organic nitrogen stock and a 9% higher soil organic carbon (C) stock. Additionally, BU reduced life–cycle reactive N (Nr) losses and the N footprint by 10%, and lowered greenhouse gas (GHG) emissions and the C footprint by 7%. From an economic analysis perspective, BU demonstrated comparable private profitability and a 3% greater ecosystem economic benefit. Therefore, BU under the optimal N rate has the potential to substitute split applications of common urea in the long–term and can be regarded as a sustainable N management strategy for wheat and maize production in the NCP.

Acidic additives have garnered significant attention due to their ability to reduce ammonia (NH₃) emissions, enhance nitrogen retention, and balance function with cost-effectiveness. This study aimed to investigate the potential of oxalic acid (OA) in reducing gas emissions, promoting compost humification, and enhancing nutrient retention during the co-composting of chicken manure. Moreover, the comparative analysis of the effects and the economic benefits was conducted among OA groups with varying concentrations (OA1: 0.03 mol·kg⁻¹, OA2: 0.10 mol·kg⁻¹, and OA3: 0.15 mol·kg⁻¹) and a sulfuric acid (SA) group (SA1: 0.03 mol·kg⁻¹). The results indicated that the addition of OA can extend the thermophilic phase to some extent and achieve the required composting maturity. As the amount of OA increased, the NH₃ emissions (p < 0.05) and the total nitrogen loss rate was decreased; however, this also increased the cost. No significant difference in the total nitrogen loss rate was observed between SA1 and OA1 (p < 0.05). It is worth noting that the addition of SA increased the SO₄²⁻ content, leading to an increase of 113.52% in H₂S emissions. In contrast, the addition of OA resulted in a reduction in H₂S emissions by 29.92–45.90%. In terms of economic analysis, OA1 was the most effective (OA1 > OA2 > OA3 > SA1). Thereby, OA was proved to be a good alternative for SA in the co-composting of chicken manure, and 0.03 mol·kg⁻¹ OA is recommended.