04313naa a2200289 a 450000100080000000500110000800800410001910000210006024500920008126000090017352035760018265000110375865000220376965000110379165000090380265000120381165000110382365000190383465000090385365300240386265300060388665300110389265300110390370000180391470000210393277300700395316211892001-01-05       2000    bl ---       0--  u    #d1 aCHANTIGNY, M. H.  aActive carbon pools and enzyme activities in soils amended with de-inking paper sludge.  c2000  aApplication of paper mill wastes generally improves soil organic matter content, biological activity and physical properties. However, the impact of large application rates (&gt 50 Mg ha-1) on soil microflora and their activity has not been assessed. A field study was undertaken on a well-drained clay loam and a poorly drained silty clay loam amended with de-inking paper sludge (DPS) at rates of 0 (control), 50 or 100 Mg ha-1, K2SO4-extractable C (Cext), soil water content (SWC), microbial biomass C (MBC) and different enzyme activity rates were periodically measured in soil during 1075 d following DPS incorporation. Compared with control soils, C ext content increased by 100 to 200%, and soil water content increased by 35% following incorporation of DPS at 100 Mg ha-1. Those differences decreased in time as DPS decomposed. Soil MBC increased proportionally with the rate of DPS amendment and was about twice the amount in soils amended with 100 Mg ha-1 compared with the control. Microbial quotient (ratio of MBC to total soil organic C) was greater in DPS-amended than in control soils until day 370, reflecting the input of labile C from DPS. Compared with the control, fluorescein diacetate hydrolysis and alkaline phosphatase activity rates increased by 40 to 100% when adding 50 Mg DPS ha-1. However, the rates were similar for 50 and 100 Mg DPS ha-1. We concluded that DPS promoted microbial growth and activity in the soil by improving C and water availability. However, levelling off of enzyme activity at a DPS loading rate above 50 Mg ha-1 could reflect changes in soil microbial community, or some kinetic interference or nutrient deficiency induced by excessive C input.  L'utilisation de residus de papier peut ameliorer la leneur en matiere organique, l'activite biologique et les proprietes physiques du sol. Toutefois, l'impact de doses elevees (&gt 50 Mg ha-1) sur la microflore du sol et ses activites n'a pas ete etudiee. Une etude de champ s'est deroulee sur un loam argileux bien et un loam limono-argileux mal draine amendes avec 0 (temoin) 50 ou 100 Mg ha-1 de residus de desencrage du papier (RDP). Le C extractible au K2SO4 (Cext), la teneur en eau, le C de la biomasse microbienne (CBM) et differentes activites enzymatiques ont ete suivies pendant 1075 jours suivant l'incorporation des RDP. Les teneurs en Cext ont augmente de 100 a 200%, alors que la teneur en eau a augmente de 35% suite a l'ajout de 100 Mg ha-1 de RDP. Ces augmentations ont graduellement disparues a mesure que les RDP se sont decomposes. Le CBM a augmente de facon proportionnelle a la dose de RDP et etait deux fois plus eleve dans le sol amende avec 100 Mg ha-1 que dans le sol temoin. Le quotient microbien (rapport CBM sur C organique total) a ete plus eleve dans les sols avec RDP que dans les sols temoins jusqu'au jour 370, ce qui reflete l'apport de C disponible provenant des RDP. Les activites de la phosphatase alcaline et d'hydrolyse du diacetate de fluorescine ont augmente de 40 a 100 % suit a l'incorporation de 50 Mg ha-1 de RDP. Les niveaux d'activite ont toutefois ete similaires dans les sols recevant 50 ou 100 Mg ha-1 de RDP. Nous concluons que les RDP ont stimule la croissance et l'activite microbiennes en ameliorant la disponitilite de l'eau et du C du sol. Toutefois, le plafonnement des activites enzymatiques a des doses &gt 50 Mg ha-1 de RDP pourrait etre le reflet d'une modification des communautes microbiennes ou de la cinetique des reactions enzymatique, ou d'une deficience en nutriments causes par un apport excessif de C.  acarbon  amicrobial biomass  asludge  asoil  aCarbono  aEnzima  aRede de Esgoto  aSolo  aBiomassa microbiana  aC  aEnzyme  aEsgoto1 aANGERS, D. A.1 aBEAUCHAMP, C. J.  tCanadian Journal of Soil Science, Ottawagv. 80, p. 99-105, 2000.