## 4 Discussion  
The study shows that pyrolyzing poultry feathers and bones offers a viable solution for creating biochar-based soil amendments. The optimized pyrolysis temperature of 500 \({}^{\circ}\)C yields a stable biochar with properties proper to enhancing soil quality. The high nitrogen content observed in biochar derived from poultry feathers and bones supports nutrient enrichment, essential for soil fertility in degraded landscapes. Lower pyrolysis temperatures retained higher char yields, which are critical for maximizing soil-conditioning properties. The paper outcomes not only contribute to sustainable waste management but also address soil fertility and water-management challenges, an integrated approach that is not addressed in many other similar studies. Furthermore, the application of this biochar in compartmentalized furrows significantly enhances moisture retention and improves soil structure. This implicitly improves other soil performances such as erosion risk reductions, which is essential for soils on slopes or in regions prone to degradation. The integration of furrow diking with biochar application offers multiple ecological and agricultural benefits, particularly on sloped or erosion-prone soils. This combination promotes water retention by trapping runoff, and also stabilizes the toposoil, which is often a limiting factor in challenging terrains. Compared to conventional biochar applications, the compartmentalized furrows increase biochar's efficacy by ensuring it remains within the soil matrix, improving its longevity and reducing the need for repeated applications. The study also highlights the potential of this approach for reducing poultry-processing waste through a circular agricultural model. Converting waste into soil amendments can simultaneously address waste-management issues and enhance sustainable agricultural practices. However, further studies are required to evaluate long-term effects on soil microbial activity and nutrient cycling, as well as the potential toxicity of tar byproducts, which could impact surrounding ecosystems if not managed properly. The distinct behaviors observed between feathers and bones during pyrolysis--such as varying devolatilization times and char yields--indicate that tailored processing conditions could further optimize biochar characteristics for specific agricultural applications. Figure 11 shows biochar's impact on moisture retention in challenging soils, highlighting a significant improvement in the soil's ability to retain water after biochar application. This increase in moisture retention is likely high due to biochar's high surface area and porous structure, which can hold water and release it slowly over time. The findings suggest that biochar acts as a water reservoir within the soil, which is particularly valuable in challenging terrains prone to rapid drainage or low water availability. Improved moisture retention can be transformative for degraded soils, enhancing plant growth by maintaining a more stable water supply. The application of biochar significantly improves soil structure across various depths, as evidenced by a notable reduction in soil compaction. This improvement is attributed to biochar's porous structure, which enhances soil aeration and water infiltration, ultimately promoting better root growth potential. The improvement was most pronounced in the toposoil layers, where biochar was applied directly, suggesting its efficacy in creating a more favorable environment for plant roots and microbial activity at shallower depths. These results align with prior research that shows that biochar's capacity to increase porosity can mitigate soil compaction issues that are common in degraded or heavily trafficked soils. By reducing bulk density and enhancing water retention, biochar application in compacted soils could help sustain crop yields, particularly in areas with limited water availability.