Influence of variable biochar concentration on yield-scaled nitrous oxide emissions, Wheat yield and nitrogen use...

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Nitrous oxide (N2O) is a potent greenhouse gas emitted from agricultural soils, particularly during nitrogen fertilizer conversion.
• Ammonium-based fertilizers contribute to N2O emissions through nitrification, a process favored in semi-arid environments like Pakistan.
• Biochar application has shown potential in reducing N2O emissions, but data from semi-arid regions is limited.

Purpose of the Study:

• To investigate the impact of varying biochar rates on yield-scaled N2O emissions in wheat cultivation.
• To assess the effects of biochar on wheat yield and nitrogen use efficiency (NUE) in urea-amended soils.
• To determine the efficacy of biochar as a mitigation strategy for N2O emissions in semi-arid agricultural systems.

Main Methods:

• Field experiment conducted on wheat (Triticum aestivum L.) using a randomized complete block design with four replications.
• Treatments included control, sole urea application (150 kg N ha⁻¹), and combinations of urea with two biochar rates (5 Mg ha⁻¹ and 10 Mg ha⁻¹).
• Measurements included total N2O emissions, yield-scaled N2O emissions, wheat biomass, grain yield, total nitrogen uptake, and NUE.

Main Results:

• Biochar application (5 and 10 Mg ha⁻¹) reduced total N2O emissions by 27% and 35%, respectively, compared to sole urea.
• Yield-scaled N2O emissions were 34% and 46% lower with urea + 5 Mg biochar and urea + 10 Mg biochar, respectively.
• Wheat above-ground biomass, grain yield, N uptake, and NUE increased by 24-38%, 9-13%, 12-27%, and 35-43%, respectively, with biochar amendments.

Conclusions:

• Biochar application effectively mitigates N2O emissions from urea-amended soils in semi-arid environments.
• Increased ammonium (NH4⁺) retention by biochar likely limited nitrification, reducing N2O production.
• Biochar amendment presents a viable strategy for enhancing wheat productivity and reducing greenhouse gas emissions in semi-arid agriculture.