The impact of activated carbon on NO3−‐N, NH4+‐N, P and K leaching in relation to fertilizer use

Summary The ability of light‐textured soils to retain nutrients and water is small. In agriculture such soils pose a risk of nutrient leaching when amended with fertilizers. This study investigated the effects of the incorporation of activated carbon ( AC ) into the soil to determine (i) if it would decrease leaching of major nutrient ions and (ii) if its effect on leaching is influenced by fertilizer use. Nitrate nitrogen ( NO 3 − ‐N ), ammonium nitrogen ( NH 4 + ‐N ), phosphorus ( P ) and potassium ( K ) leaching through two substrates (sandy loam soil ( S ) and a sandy loam soil mixed with activated carbon ( S + AC ), which were unfertilized ( NF or control) or fertilized with inorganic fertilizer ( F ), pig slurry ( PS ), pig slurry digestate ( PD ) or sewage sludge digestate ( SD ) was studied using mini‐lysimeters. In soil enriched with AC mark K‐835 , water percolation and NO 3 − ‐N and P leaching were significantly reduced, and K leaching was increased. Ammonium nitrogen leaching was not influenced by the AC amendment. The impact of AC on NO 3 − ‐N and P leaching and water percolation did not change during the two‐year period, from which it is concluded that AC mark K‐835 prevents the leaching of NO 3 − ‐N and P and increases soil water retention ability, and thus it is beneficial for light‐textured soils.