Researchers evaluated the agronomic effectiveness of sewage-sludge-based organomineral fertilizers produced through different technologies as a sustainable alternative to conventional mineral fertilization for tropical pasture systems. The investigation focused on Urochloa brizantha cultivar Paiaguás, a forage grass widely cultivated across tropical regions for livestock feeding and soil cover. While mineral fertilizers are traditionally utilized to meet plant nutritional demands, their production relies on energy-intensive, non-renewable resources that generate greenhouse gas emissions and high economic costs. Organomineral fertilization combines organic residues, such as sewage sludge and sawdust, with essential mineral nutrients to enhance plant nutrition, improve soil microbial activity, and recycle urban and agricultural waste products.

The findings revealed that granulated biochar organomineral fertilizer increased shoot dry matter production by up to forty-three percent compared to other organomineral formulations, performing equally as well as conventional mineral fertilization. Throughout the one hundred twenty day greenhouse trial, plants treated with granulated biochar exhibited superior growth and development. Furthermore, the granulated biochar treatment increased phosphorus accumulation in plant shoots by forty-nine percent compared to mineral fertilization. Total phosphorus accumulation reached values close to those achieved with mineral inputs, outperforming alternative organomineral mixtures significantly. Both the granulated biochar and mineral treatments also produced the highest total accumulations of nitrogen, magnesium, and sulfur within the plant tissues.

The application of organomineral fertilizers also induced positive changes in soil chemical attributes by improving nutrient availability and reducing environmental risks. Specifically, granulated biochar fertilization increased the cation exchange capacity of the soil compared to mineral treatments. The organic compounds and biochar matrix helped reduce potential acidity and aluminum toxicity, creating a more favorable root environment that encouraged robust plant uptake. Soils treated with organomineral formulations showed substantial increases in organic carbon content, which enhances long-term soil health, moisture retention, and structural stability.

Ultimately, the research confirms that converting sewage sludge and sawdust into granulated biochar organomineral fertilizer offers an efficient and environmentally sound approach to agricultural management. By matching the productive performance of mineral fertilizers while simultaneously improving soil chemical properties, this strategy supports circular economy goals and sustainable livestock production in tropical regions.

Source: Bicalho, S. F., Viana, L. B., Pegoraro, R. F., Almeida Neta, M. N., Barroso, A. M. F., Tuffi Santos, L. D., & Colen, F. (2026). Organomineral fertilization with sewage sludge on the production and nutrient accumulation in Urochloa brizantha cv. Paiaguás. Environmental Science and Pollution Research.