Environmental Science · Environmental Chemistry
Nitrogen fertilizer increased nitrous oxide emissions from Chinese croplands by an estimated 237.8% compared with unfertilized controls in a meta-analysis of 462 field observations. The size of the increase varied among regions and was also linked to fertilizer rates, fertilizer type, cropping systems, weather and soil texture.
Hydrogen peroxide-treated biochar made from waste tyres removed 99% of phosphorus from a simulated wastewater solution, compared with 20% for untreated tyre biochar. After capturing phosphorus, the treated material was used in nutrient-poor soil, where maize biomass was nearly three times higher than with untreated material or no added fertiliser.
A study in *Scientific Reports* tested phosphorus recovered from human urine as a fertilizer in a tropical Oxisol planted with maize. The urine-derived struvite supported substantial shoot growth and left higher residual phosphorus in soil after cultivation, suggesting it released phosphorus in a way that better resisted soil “locking up.”
