Biology and Fertility of Soils, July, 2011, Vol.47(5), p.483(12)
Byline: Nadine Jager (1), Claus Florian Stange (2), Bernard Ludwig (3), Heiner Flessa (4) Keywords: [N.sub.2]O; CO.sub.2; SOC; Long-term fertilization Abstract: Increasing organic matter stocks in soils reduce atmospheric carbon dioxide (CO.sub.2), but they may also promote emissions of nitrous oxide ([N.sub.2]O) by providing substrates for nitrification and denitrification and by increasing microbial O.sub.2 consumption. The objectives of this study were to determine the effects of fertilization history, which had resulted in different soil organic matter stocks on (1) the emission rates of [N.sub.2]O and CO.sub.2 at a constant soil moisture content of 60% water-holding capacity, (2) the short-term fluxes of [N.sub.2]O and CO.sub.2 following the application of different fertilizers (KNO.sub.3 vs. farmyard manure from cattle) and (3) the response to a simulated heavy rainfall event, which increased soil moisture to field capacity. Soil samples from different treatments of three long-term fertilization experiments in Germany (Methau, Sproda and Bad Lauchstadt) were incubated in a laboratory experiment with continuous determination of [N.sub.2]O and CO.sub.2 emissions and a monitoring of soil mineral N. The long-term fertilization treatments included application of mineral N (Methau and Sproda), farmyard manure + mineral N (Methau and Sproda), farmyard manure deposition in excess (Bad Lauchstadt) and nil fertilization (Bad Lauchstadt). Long-term addition of farmyard manure increased the soil organic C (SOC) content by 55% at Methau (silt loam), by 17% at Sproda (sandy loam) and by 88% at Bad Lauchstadt (silt loam extreme treatment which does not represent common agricultural management). Increased soil organic matter stocks induced by long-term application of farmyard manure at Methau and Sproda resulted in slightly increased [N.sub.2]O emissions at a soil moisture content of 60% water-holding capacity. However, the effect of fertilization history and SOC content on [N.sub.2]O emissions was small compared to the short-term effects induced by the current fertilizer application. At Bad Lauchstadt, high [N.sub.2]O emissions from the treatment without fertilization for 25 years indicate the importance of a sustainable soil organic matter management to maintain soil structure and soil aeration. Emissions of [N.sub.2]O following the application of nitrate and farmyard manure differed because of their specific effects on soil nitrate availability and microbial oxygen consumption. At a soil moisture content of 60% water-holding capacity, fertilizer-induced emissions were higher for farmyard manure than for nitrate. At field capacity, nitrate application induced the highest emissions. Our results indicate that feedback mechanisms of soil C sequestration on [N.sub.2]O emissions have to be considered when discussing options to increase soil C stocks. Author Affiliation: (1) Soil Science of Temperate and Boreal Ecosystems, Busgen-Institute, University of Gottingen, Busgenweg 2, 37077, Gottingen, Germany (2) Helmholtz Centre for Environmental Research--UFZ, Department Soil Physics, Theodor-Lieser-Strasse 4, 06120, Halle/Saale, Germany (3) Department of Environmental Chemistry, University of Kassel, Nordbahnhofstr. 1a, 37213, Witzenhausen, Germany (4) Institute of Agricultural Climate Research, Johann Heinrich von Thunen-Institut, Bundesallee 50, 38116, Braunschweig, Germany Article History: Registration Date: 03/03/2011 Received Date: 24/08/2010 Accepted Date: 03/03/2011 Online Date: 29/03/2011
Soil Carbon ; Green Technology ; Silt ; Soils ; Rain ; Soil Aeration ; Air Pollution Control ; Soil Moisture ; Ecosystems ; Atmospheric Carbon Dioxide ; Soil Structure ; Soil Microbiology ; Emissions (Pollution) ; Nitrous Oxide ; Denitrification ; Nitrification ; Organic Fertilizers
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