Combined biochar and nitrogen application stimulates enzyme activity and root plasticity

Area of Science:

• Soil Science
• Agronomy
• Environmental Science

Background:

• Biochar (BC) and nitrogen (N) fertilizers are common soil amendments.
• Their combined effects on plant-soil interactions, enzyme activities, and nutrient cycling are not fully understood.

Purpose of the Study:

• To investigate the individual and combined effects of BC and N on soil enzyme activities, N and P cycling, and root plasticity using a split-root system.
• To elucidate the mechanisms behind plant-soil interactions under different amendment strategies.

Main Methods:

• A split-root system in rhizoboxes was used with treatments: BC/Control, N/Control, and BC/N.
• Soil properties, enzyme activities (β-glucosidase, leucine aminopeptidase), N and P availability, root morphology, and plant biomass were analyzed.
• Wheat straw-derived biochar (15 g kg⁻¹ soil) and KNO₃-N (0.05 g kg⁻¹ soil) were applied.

Main Results:

• Combined BC/N application yielded the highest plant biomass (0.91 g pot⁻¹).
• Biochar significantly increased root length (1.4-1.8 times) by improving soil structure and P availability, independent of N.
• Biochar boosted β-glucosidase and leucine aminopeptidase activities (33-39%) in BC/N soil, indicating enhanced C, N, and P cycling.

Conclusions:

• Combined BC/N application significantly enhances plant growth and nutrient cycling compared to single applications.
• Biochar stimulates root growth and enzyme activities, while N fertilization further boosts enzyme activity, leading to synergistic benefits.
• This combined approach offers a sustainable strategy to overcome nutrient limitations and maintain crop productivity by enhancing root-microbial interactions.