Gross N mineralization and immobilization was examined in soil amended with compost and sewage sludge on seven occasions during a year using N-15 pool dilution and enrichment techniques. Gross N mineralization was initially stimulated with both wastes and accelerated through the first 112 days of incubation, peaking at 5 mg N.kg(-1).d(-1) with compost compared with 4 mg N.kg(-1).d(-1) in control and sludge-treated soil. The magnitudes of mineralization rates exceeded those of immobilization by on average 6.3 ( compost) and 11.4 ( sludge) times, leading to a persistent net N mineralization cumulating up to 160 mg N.kg(-1) soil(compost) and 54 mg N.kg(-1) soil (sludge) over the season from May to November. The numerical model FLUAZ comprehensively predicted rates of gross mineralization and immobilization. Sludge exhibited an early season N-release, whereas compost released only 10% of the N during the first two months of incubation. This indicates that compost should be applied well in advance of sowing in order to match crop N demands.
|Publication status||Published - 2002|
|Event||11th Nitrogen workshop - Reims, France|
Duration: 9 Sep 2001 → 12 Sep 2001
|Conference||11th Nitrogen workshop|
|Period||09/09/2001 → 12/09/2001|