A recent study by Shin et al., published in the Korean Journal of Agricultural Science, investigates the impact of poultry manure-based biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More on soil health and crop yield in Saemangeum, South Korea’s reclaimed agricultural land. The researchers found that applying 10.0 Mg·ha⁻¹ of poultry manure biochar without rice husk significantly improved soil nutrient levels and increased lettuce yield to 33.52 Mg·ha⁻¹.

Reclaimed Soils and the Need for Soil Improvement

Reclaimed agricultural soils, like those in Saemangeum, often suffer from poor nutrient content and low organic matter, limiting their productivity. Poultry manure is rich in nitrogen and phosphorus, making it a valuable soil amendmentA soil amendment is any material added to the soil to enhance its physical or chemical properties, improving its suitability for plant growth. Biochar is considered a soil amendment as it can improve soil structure, water retention, nutrient availability, and microbial activity.   More. However, improper handling can cause environmental issues such as odor and greenhouse gas emissions. Converting poultry manure into biochar through pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More offers a potential solution by stabilizing nutrients and reducing environmental risks.

Study Design: Testing Different Biochar Compositions

The researchers tested biochars made from poultry manure with varying proportions of rice husk (0–100%) at a pyrolysis temperature of 350°C. They applied different biochar treatments to soil at three rates (1.0, 5.0, and 10.0 Mg·ha⁻¹) and measured soil properties, nutrient availability, and lettuce yield.

Key Findings

1. Soil Nutrients and Organic Matter:

• Increasing the rice husk proportion in biochar lowered pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More, electrical conductivity, and nutrient content (N, K₂O, CaO, MgO).
• Higher rice husk content led to increased organic matter (OM) and total carbon (T-C).
• Biochar application at 5.0 Mg·ha⁻¹ or more significantly improved soil nutrient levels.

2. Lettuce Yield:

• Lettuce growth responded positively to biochar, with yields increasing as biochar application rates increased.
• The highest yield (33.52 Mg·ha⁻¹) was achieved with 10.0 Mg·ha⁻¹ of poultry manure biochar containing no rice husk.
• Biochar treatments generally outperformed both the control and urea-only fertilizer treatments.

3. Optimizing Biochar Composition:

• Minimizing the rice husk proportion in poultry manure-based biochar was most effective for improving soil nutrients.
• Conversely, increasing rice husk content enhanced organic matter and carbon sequestration.

Implications for Sustainable Agriculture

This study demonstrates that poultry manure biochar can be a powerful tool for improving soil fertility in reclaimed lands. By adjusting biochar composition, farmers can balance nutrient availability with organic matter enrichment, enhancing both productivity and soil health. These findings support biochar’s role in sustainable agriculture by reducing waste, improving soil properties, and boosting crop yields.

Future research could explore long-term impacts and optimal biochar formulations for different crops and soil types.

SOURCE: Shin, J. H., Kang, Y. G., Lee, J. Y., Kim, J. H., & Oh, T. K. (2024). Effect of poultry manure biochar on soil nutrition and carbon improvement in Saemangeum reclaimed soils. Korean Journal of Agricultural Science, 51, 643–654. https://doi.org/10.7744/kjoas.510418