Nitrate capture and slow release in biochar amended compost and soil

• DOI: 10.1371/journal.pone.0171214
• Publication Date: 2017-02-15T15:22:13Z
• Authors: Nikolas Hagemann; Claudia I. Kammann; Hans-Peter Schmidt; Andreas Kappler; Sebastian Behrens
• Keywords: Nitrates; Time Factors; Science; Q; R; Temperature; Sterilization; Hydrogen Peroxide; 04 agricultural and veterinary sciences; 6. Clean water; Soil; Charcoal; Ammonium Compounds; Medicine; 0401 agriculture, forestry, and fisheries; Fertilizers; Research Article

Slow release of nitrate by charred organic matter used as a soil amendment (i.e. biochar) was recently suggested potential mechanism nutrient delivery to plants which may explain some agronomic benefits biochar. So far, isolated soil-aged and composted biochar particles were shown considerable amounts only in extended (>1 h) extractions ("slow release"). In this study, we quantified ammonium biochar-amended compost during up 167 h repeated six consecutive steps determine the effect on overall mineral nitrogen retention. We composts produced from mixed manures amended with three contrasting biochars prior aerobic composting loamy that years analysis compared both non-biochar controls. Composts extracted 2 M KCl at 22°C 65°C, after sterilization, treatment H2O2, removing or without any modification. Soils 22°C. Ammonium continuously released extractions, independent is probably result abiotic ammonification. For pure compost, extraction complete 1 h, while composts, 30% total subsequent steps. The 70% its amount 58%. However, doubled extractable nitrate. Thus, capture can be relevant contribution retention agroecosystems. Our results also indicate soils frequently underestimated. Furthermore, could prevent loss agroecosystems developed into slow-release fertilizers reduce global N fertilizer demands.