Background Biochar (BC) is an excellent strategy for reducing greenhouse gas emissions. However, the impacts of BC in combination with sheep manure (SM) and nitrogen (N) fertilizers on nitrogen cycling genes, carbon sequestration, rice productivity, and nitrous oxide (N2O) emissions are not understood. Thus, this study was designed to determine the impacts of combined BC, SM, and N fertilizers on nitrogen cycling genes, carbon sequestration, rice productivity, and N2O emissions. Methods The study included the following treatments: T1: control, T2: 150 kg N ha− 1 (100%), T3: biochar (33.18 t ha− 1), T4: sheep manure (3.75 t ha− 1), T5: 75 kg N ha− 1 (50%) + biochar (50%: 16.59 t ha− 1), T6: 75 kg N ha− 1 (50%) + sheep manure (50%: 1.87 t ha− 1); and T7: 75 kg N ha− 1 (50%) + biochar (25%: 8.29 t ha− 1) + sheep manure (25%: 0.937 t ha− 1). Results Integrated BC, SM, and N application increased the soil pH and NH+ 4-N content and decreased the availability of NO− 3-N, leading to a substantial reduction in N2O emissions. Co-application of BC, SM, and N decreased the cumulative N2O emissions by 223% and 197%, respectively, during the first and second years. Integrated BC, SM, and N application also increased soil organic carbon (SOC), microbial biomass carbon (MBC), and carbon fractions (water-soluble organic carbon (WSOC), easily oxidizable carbon (EOC), and particulate organic carbon (POC)). The same treatment combination also increased the carbon liability index (CLI: 69.89 and 70.51%), carbon pool index (CPI: 95% and 114%), and carbon management index (CMI: 234.41 and 264.92%) over the control in both years. Moreover, BC, SM, and N also decreased AOA and nirK abundance and increased nosZ abundance, leading to lower N2O emissions. Additionally, the combined use of BC, SM, and N significantly increased the kernel yield (66.67 and 83.34%), biomass yield (31.77 and 51.26%), kernel weight (104 and 106%), and harvest index (19.11 and 21.29%) over the control in both years. Conclusion Therefore, BC and SM combined with reduced N application may be suitable strategies for improving rice productivity and reducing N2O emissions from paddy field. These findings also highlight the viability of combining BC and SM with reduced N application to achieve environmental sustainability while aligning with global climate resilience goals.

Biochar and Sheep Manure with Reduced Nitrogen Application Increases Rice Productivity and Mitigates N₂O Emissions in Paddy Fields

期刊论文
发表日期：

2025年9月23日

查看全文

Tahir Abbas Khan,
Huang Guoqin,
Muhammad Umair Hassan,
Mehmood Ali Noor,
Muhammad Aamer,
Tahani A.Y. Asseri,
Rehab O. Elnour

摘要

Background

Biochar (BC) is an excellent strategy for reducing greenhouse gas emissions. However, the impacts of BC in combination with sheep manure (SM) and nitrogen (N) fertilizers on nitrogen cycling genes, carbon sequestration, rice productivity, and nitrous oxide (N₂O) emissions are not understood. Thus, this study was designed to determine the impacts of combined BC, SM, and N fertilizers on nitrogen cycling genes, carbon sequestration, rice productivity, and N₂O emissions.

Methods

The study included the following treatments: T1: control, T2: 150 kg N ha^− 1 (100%), T3: biochar (33.18 t ha^− 1), T4: sheep manure (3.75 t ha^− 1), T5: 75 kg N ha^− 1 (50%) + biochar (50%: 16.59 t ha^− 1), T6: 75 kg N ha^− 1 (50%) + sheep manure (50%: 1.87 t ha^− 1); and T7: 75 kg N ha^− 1 (50%) + biochar (25%: 8.29 t ha^− 1) + sheep manure (25%: 0.937 t ha^− 1).

Results

Integrated BC, SM, and N application increased the soil pH and NH⁺ ₄-N content and decreased the availability of NO⁻ ₃-N, leading to a substantial reduction in N₂O emissions. Co-application of BC, SM, and N decreased the cumulative N₂O emissions by 223% and 197%, respectively, during the first and second years. Integrated BC, SM, and N application also increased soil organic carbon (SOC), microbial biomass carbon (MBC), and carbon fractions (water-soluble organic carbon (WSOC), easily oxidizable carbon (EOC), and particulate organic carbon (POC)). The same treatment combination also increased the carbon liability index (CLI: 69.89 and 70.51%), carbon pool index (CPI: 95% and 114%), and carbon management index (CMI: 234.41 and 264.92%) over the control in both years. Moreover, BC, SM, and N also decreased AOA and nirK abundance and increased nosZ abundance, leading to lower N₂O emissions. Additionally, the combined use of BC, SM, and N significantly increased the kernel yield (66.67 and 83.34%), biomass yield (31.77 and 51.26%), kernel weight (104 and 106%), and harvest index (19.11 and 21.29%) over the control in both years.

Conclusion

Therefore, BC and SM combined with reduced N application may be suitable strategies for improving rice productivity and reducing N₂O emissions from paddy field. These findings also highlight the viability of combining BC and SM with reduced N application to achieve environmental sustainability while aligning with global climate resilience goals.

Biochar and Sheep Manure with Reduced Nitrogen Application Increases Rice Productivity and Mitigates N2O Emissions in Paddy Fields

摘要

Biochar and Sheep Manure with Reduced Nitrogen Application Increases Rice Productivity and Mitigates N₂O Emissions in Paddy Fields