Organic fertilizer is an effective substitute for mineral fertilizer that improves crop yield and is environmentally friendly. However, the effects of substitution often vary due to complicated interactions among the organic fertilizer substitution rate (Rs), total nutrient supply, and type of cropping system used. We performed a meta-analysis of 133 maize studies, conducted worldwide, to assess maize yield and environmental performance with substitution of mineral fertilizer with organic fertilizer. At an equivalent nitrogen (N) rate, substituting mineral fertilizer with organic fertilizer increased maize yield by 4.22%, reduced NH₃ volatilization by 64.8%, reduced N leaching and runoff by 26.9%, and increased CO₂ emissions by 26.8%; however, it had no significant effect on N₂O or CH₄ emissions. Moreover, substitution with organic fertilizer increased the soil organic carbon sequestration rate by 925 kg C ha⁻¹ yr⁻¹ and decreased the global warming potential by 116 kg CO₂ eq ha⁻¹ compared with mineral fertilizer treatment. The net global warming potential after organic fertilizer substitution was −3507 kg CO₂ eq ha⁻¹, indicating a net carbon sink. Furthermore, the effect of organic fertilizer substitution varied with the fertilization rate, Rs, and treatment duration. Maize yield and nitrogen use efficiency tended to increase with increasing N application rate following substitution of mineral fertilizer with organic fertilizer. Full substitution reduced N losses more than partial substitution. Further analysis revealed that the yield-optimal Rs for organic N in maize production was 40–60%. Moreover, maize yield and nitrogen use efficiency were further increased after long-term (≥ 3 years) combined use of organic and mineral fertilizers. These findings suggest that rational use of organic and mineral fertilizers improves maize productivity, increases soil organic carbon sequestration, and reduces N and C losses.

Gongbuzeren, J. Zhang, M. Zhuang, J. Zhang, and L. Huntsinger. 2021. Mitigating the impacts of fragmented land tenure through community-based institutional innovations: two case study villages from Guinan County of Qinghai Province, China. Ecology and Society 26(2):15. https://doi.org/10.5751/ES-12326-260215

Rising CO₂ and O₃ concentrations significantly affect plant growth and can alter nutrient cycles. However, the effects of elevated CO₂ and O₃ concentrations on the nutrient dynamics of bamboo species are not well understood. In this study, using open top chambers (OTCs), we examined the effects of elevated CO₂ and O₃ concentrations on leaf biomass and nutrient (N, P, and K) dynamics in two bamboo species, Phyllostachys edulis (Carrière) J.Houz. and Oligostachyum lubricum (wen) King f. Elevated O₃ significantly decreased leaf biomass and nutrient uptake of both bamboo species, with the exception of no observed change in K uptake by O. lubricum. Elevated CO₂ increased leaf biomass, N and K uptake of both bamboo species. Elevated CO₂ and O₃ simultaneously had no significant influence on leaf biomass of either species but decreased P and N uptake in P. edulis and O. lubricum, respectively, and increased K uptake in O. lubricum. The results indicate that elevated CO₂ alleviated the damage caused by elevated O₃ in the two bamboo species by altering the uptake of certain nutrients, which further highlights the potential interactive effects between the two gases on nutrient uptake. In addition, we found differential responses of nutrient dynamics in the two bamboo species to the two elevated gases, alone or in combination. These findings will facilitate the development of effective nutrient management strategies for sustainable management of P. edulis and O. lubricum under global change scenarios.