Assessing Nitrogen Release from Organic Fertilizers with Biochar Addition in a Laboratory Incubation Trial
Year: 2026
Type: article
Abstract: In temperate agricultural systems, biochar is commonly added to organic fertilizers before field application. The impact of biochar on nitrogen (N) release from organic fertilizers (based on equivalent N input) remains largely unexplored. To assess net N release from different organic fertilizers (with biochar addition), 104-day laboratory incubations were conducted. Net N release was measured from cattle slurry, dairy manure compost, and grass-clover compost. Each fertilizer was co-fermented or co-composted with biochar at rates of 0, 500, 1,000, or 2,000 kg ha − 1 , derived from two manufacturing processes. All amendments were applied at an N rate of 1,200 kg ha − 1 . In addition, the effect of pristine biochar (0, 500, 1,000, 2,000, and 20,000 kg ha − 1 ) on N release from the experimental soil was investigated. Net N release was highest from cattle slurry (34.4%), followed by grass-clover compost (17.1%) and manure compost (7.4%). Biochar addition reduced net N release from all fertilizers, e.g., for cattle slurry, to 30.2% at 500 kg ha − 1 , 28.6% at 1,000 kg ha − 1 , and 23.5% at 2,000 kg ha − 1 biochar C. Pristine biochar had negligible effects on soil N release at low rates but slightly reduced soil N release at a high rate. These results highlight the role of on-farm biochar pretreatment on the N fertilizer value of organic amendments. To maintain crop yields, fertilizer requirement calculations should account for potential N limitations associated with biochar addition, and N fertilizer rates may need to be tailored.
Institution: Technical University of Munich
Language: English
Subfield: Soil Science
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,190
OpenAlex ID: W7165116573