Biochar type and pyrolysis temperature effects on soil quality indicators and structural stability.

Area of Science:

• Soil Science
• Environmental Science
• Agronomy

Background:

• Arid soils often have low organic matter, limiting their quality and productivity.
• Natural amendments, particularly biochar, offer a sustainable solution for soil improvement.
• Understanding feedstock type and pyrolysis temperature is crucial for optimizing biochar efficacy.

Purpose of the Study:

• To evaluate the impact of corn residue and poultry manure biochars on key soil quality indicators.
• To assess the influence of feedstock type, application rate, and pyrolysis temperature on soil properties.
• To determine the effectiveness of biochar in enhancing soil organic carbon (SOC) and structural stability.

Main Methods:

• Sandy loam soil was amended with corn residue (CR) and poultry manure (PM) feedstocks and their biochars at 1, 2, and 4% rates.
• Biochars were produced via slow pyrolysis at 350°C and 650°C.
• Soil organic carbon (SOC), hot-water soluble carbohydrates (HWSC), basal soil respiration (BSR), and structural stability (HEMC indices) were measured after maize cultivation.

Main Results:

• All treatments significantly increased SOC (1.5-10x), HWSC (1-7x), and structural stability indices (VDPR 1.5-3.5x, SR 1-3x).
• Higher pyrolysis temperatures generally decreased SOC, BSR, and aggregate stability.
• Corn residue biochar, especially at higher pyrolysis temperatures, was more effective than poultry manure biochar due to lower sodium adsorption ratio (SAR).

Conclusions:

• Biochar application, particularly from corn residue, is a viable strategy to enhance soil organic matter and structural stability in arid soils.
• Pyrolysis temperature significantly influences biochar's impact on soil properties, with higher temperatures potentially reducing some benefits.
• Poultry manure biochar's effectiveness is limited by its higher SAR, leading to poorer soil structural stability compared to corn residue biochar.