title: Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land.
abstract: In many temperate agricultural areas, riparian forests have been converted to cultivated land, and only narrow strips of herbaceous vegetation now buffer many farm streams. The afforestation of these riparian zones has the potential to increase carbon (C) storage in agricultural landscapes by creating a new biomass sink for atmospheric CO2. Occurring at the same time, the storage of nitrogen (N) and phosphorus (P) in plant biomass, is an important water quality function that may greatly vary with types of riparian vegetation. The objectives of this study were (1) to compare C, N and P storage in aboveground, belowground and detrital biomass for three types of riparian vegetation cover (9-year-old hybrid poplar buffers, herbaceous buffers and natural woodlots) across four agricultural sites and (2) to determine potential vegetation cover effects on soil nutrient supply rate in the riparian zone. Site level comparisons suggest that 9-year-old poplar buffers have stored 9-31 times more biomass C, 4-10 times more biomass N, and 3-7 times more biomass P than adjacent non managed herbaceous buffers, with the largest differences observed on the more fertile sites. The conversion of these herbaceous buffers to poplar buffers could respectively increase C, N and P storage in biomass by 3.2-11.9 t/ha/yr, 32-124 kg/ha/yr and 3.2-15.6 kg/ha/yr, over 9 years. Soil NO3 and P supply rates during the summer were respectively 57% and 66% lower in poplar buffers than in adjacent herbaceous buffers, potentially reflecting differences in nutrient storage and cycling between the two buffer types. Biomass C ranged 49-160 t/ha in woodlots, 33-110 t/ha in poplar buffers and 3-4 t/ha in herbaceous buffers. Similar biomass C stocks were found in the most productive poplar buffer and three of the four woodlots studied. Given their large and varied biomass C stocks, conservation of older riparian woodlots is equally important for C balance management in farmland. In addition, the establishment of poplar buffers, in replacement of non managed herbaceous buffers, could rapidly increase biomass C, N and P storage along farm streams, which would be beneficial for water quality protection and global change mitigation.
authors.affiliation: Fiducie de recherche sur la forêt des Cantons-de-l'Est/Eastern Townships Forest Research Trust, 1 Rue Principale, Saint-Benoît-du-Lac, QC J0B 2M0, Canada; Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888 succ. Centre-ville, Montréal, QC H3C 3P8, Canada. Electronic address: fortier.julien@courrier.uqam.ca.
authors.forename: Julien
authors.initials: J
authors.lastname: Fortier
authors.affiliation: Fiducie de recherche sur la forêt des Cantons-de-l'Est/Eastern Townships Forest Research Trust, 1 Rue Principale, Saint-Benoît-du-Lac, QC J0B 2M0, Canada. Electronic address: btruax@frfce.qc.ca.
authors.forename: Benoit
authors.initials: B
authors.lastname: Truax
authors.affiliation: Fiducie de recherche sur la forêt des Cantons-de-l'Est/Eastern Townships Forest Research Trust, 1 Rue Principale, Saint-Benoît-du-Lac, QC J0B 2M0, Canada; Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada. Electronic address: daniel.gagnon@uregina.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gagnon
authors.affiliation: Fiducie de recherche sur la forêt des Cantons-de-l'Est/Eastern Townships Forest Research Trust, 1 Rue Principale, Saint-Benoît-du-Lac, QC J0B 2M0, Canada. Electronic address: france.lambert@frfce.qc.ca.
authors.forename: France
authors.initials: F
authors.lastname: Lambert
mesh_terms: D000383:Agriculture; D018533:Biomass; D002244:Carbon / Q000032:analysis; D004784:Environmental Monitoring; D006801:Humans; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D010944:Plants; D014197:Trees
chemical_list: D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
keywords: Aboveground biomass; Agroforestry; Belowground biomass; C, N and P concentrations; Detrital biomass; Soil nutrient availability (supply rates)