TY  - JOUR
A1  - Hund, Silja V.
A1  - Brown, Sandra
A1  - Lavkulich, Les M.
A1  - Oswald, Sascha
T1  - Relating P Lability in Stream Sediments to Watershed Land Use via an Effective Sequential Extraction Scheme
JF  - Water, air & soil pollution : an international journal of environmental pollution
N2  - High applications of P fertilizers and manure are general practice in intensive agriculture and may cause eutrophication in adjacent streams. Bioavailability of P can be estimated by sequential extractions commonly used for soil or sediment. A single combined method may facilitate more effective comparisons of topsoils and adjoining stream sediments, and enhance management decisions. In this study, the suitability of an established soil P sequential extraction was tested on stream bed sediments. The study was conducted in the Sumas River watershed in the agricultural Lower Fraser Valley, Canada. Sediment samples with differing land use (forest, low and high intensity agriculture) from 1993, 1994, 2008, and 2009 from 14 sites along the Sumas River and tributaries were used. Total sequential extraction concentrations were in agreement with aqua regia digestion (Rs=0.96) and showed consistency over the study time sequence. P fractions released by 0.5 M NaHCO3 (median 14 %), 0.1 M NaOH (33 %), and 1.0 M HCl (38 %) were significantly (alpha=0.05) higher than P released by other extractants. These three extraction steps provide a practical and time-effective assessment of P lability in stream sediments and may be used as a combined scheme for sediment and soil. Analytical results further revealed that land use has a major and characteristic impact on P lability. With a land use change from forest to intensive agriculture, results showed an increase in total P concentrations (30 to 4,000 ppm) and in P lability, in particular for the moderately labile NaOH-P fraction (20 to 50 %).
KW  - Phosphorus
KW  - Eutrophication
KW  - Availability
KW  - Sequential extraction
KW  - Agriculture
KW  - River bed sediment
Y1  - 2013
U6  - https://doi.org/10.1007/s11270-013-1643-9
SN  - 0049-6979
SN  - 1573-2932
VL  - 224
IS  - 9
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Klaus, Valentin H.
A1  - Kleinebecker, Till
A1  - Prati, Daniel
A1  - Gossner, Martin M.
A1  - Alt, Fabian
A1  - Boch, Steffen
A1  - Gockel, Sonja
A1  - Hemp, Andreas
A1  - Lange, Markus
A1  - Müller, Jörg
A1  - Oelmann, Yvonne
A1  - Pasalic, Esther
A1  - Renner, Swen C.
A1  - Socher, Stephanie A.
A1  - Türke, Manfred
A1  - Weisser, Wolfgang W.
A1  - Fischer, Markus
A1  - Hölzel, Norbert
T1  - Does organic grassland farming benefit plant and arthropod diversity at the expense of yield and soil fertility?
JF  - Agriculture, ecosystems & environment : an international journal for scientific research on the relationship of agriculture and food production to the biosphere
N2  - Organic management is one of the most popular strategies to reduce negative environmental impacts of intensive agriculture. However, little is known about benefits for biodiversity and potential worsening of yield under organic grasslands management across different grassland types, i.e. meadow, pasture and mown pasture. Therefore, we studied the diversity of vascular plants and foliage-living arthropods (Coleoptera, Araneae, Heteroptera, Auchenorrhyncha), yield, fodder quality, soil phosphorus concentrations and land-use intensity of organic and conventional grasslands across three study regions in Germany. Furthermore, all variables were related to the time since conversion to organic management in order to assess temporal developments reaching up to 18 years. Arthropod diversity was significantly higher under organic than conventional management, although this was not the case for Araneae, Heteroptera and Auchenorrhyncha when analyzed separately. On the contrary, arthropod abundance, vascular plant diversity and also yield and fodder quality did not considerably differ between organic and conventional grasslands. Analyses did not reveal differences in the effect of organic management among grassland types. None of the recorded abiotic and biotic parameters showed a significant trend with time since transition to organic management, except soil organic phosphorus concentrations which decreased with time. This implies that permanent grasslands respond slower and probably weaker to organic management than crop fields do. However, as land-use intensity and inorganic soil phosphorus concentrations were significantly lower in organic grasslands, overcoming seed and dispersal limitation by re-introducing plant species might be needed to exploit the full ecological potential of organic grassland management. We conclude that although organic management did not automatically increase the diversity of all studied taxa, it is a reasonable and useful way to support agro-biodiversity.
KW  - Agri-environmental schemes
KW  - Fertilization
KW  - Fodder quality
KW  - Land-use intensity
KW  - Nitrogen
KW  - Biomass nutrient concentrations
KW  - Organic farming
KW  - Phosphorus
KW  - Species richness
KW  - Nutrient availability
Y1  - 2013
U6  - https://doi.org/10.1016/j.agee.2013.05.019
SN  - 0167-8809
VL  - 177
IS  - 3
SP  - 1
EP  - 9
PB  - Elsevier
CY  - Amsterdam
ER  -