Browsing by Subject "Treibhausgasemission"

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Effects of nitrification inhibitors and application technique on trace gas fluxes from a maize field after cattle slurry fertilization
(2019) Herr, Christina; Müller, Torsten
In a time of climate change and against the background of intensive animal husbandry and biogas production in Germany, strategies for mitigation of greenhouse gas (GHG) release and Nitrogen (N) losses from silage maize production become increasingly important, especially for organic fertilizers. Consequently, the main objective of this study was to determine the height of GHG release from silage maize production on a medium textured soil which is typical for this region in Southwest Germany and to evaluate useful fertilization opportunities to mitigate carbon dioxide (CO2) footprint per yield unit. To identify management factors improving GHG budget from silage maize, annual nitrous oxide (N2O) and methane (CH4) measurements were carried out during maize growth and subsequent black fallow at least weekly. Investigations were conducted over two years on two adjacent fields (one for each study year). Amounts of ammonia (NH3) volatilizations after fertilization and nitrate (NO3-) leaching losses were also included in GHG balances. In dependence on available data, determined or estimated values were used. Additionally, yield and N removal from maize plants were quantified. The basic treatments of this study which investigated impact of fertilizer form and application techniques, were an unfertilized control (CON), a mineral fertilization (MIN), a banded cattle slurry application by trailing hose and subsequent incorporation (INC) and a cattle slurry injection (INJ). As confirmed repeatedly, in contrast to broadcast slurry incorporation, slurry injection efficiently reduced the risk of NH3 losses by direct slurry placement into the soil, but simultaneously provoked N2O formation more strongly, probably due to the anaerobic conditions in the injection slot favoring denitrification. For reducing N2O release from slurry injection, the applicability of six single or combined nitrification inhibitors (NIs) concerning potential GHG reduction were investigated. This N2O reduction should be reached through the desynchronized availability of carbon (C) and NO3-, derived from nitrified slurry ammonium (NH4+). Thus, in the period after slurry application, N2O losses from denitrification as well as from nitrification should be reduced through NIs. For final evaluation, collection of measured and estimated data (including direct and indirect N2O losses (NH3, NO3-), CH4 budget, pre-chain emissions from mineral fertilizer and fuel consumption) were converted into CO2 equivalents and summarized as area- or yield-related GHG balances. Except for one of the INJ treatments with NI (exclusively investigated in the first year) and one INC treatment with NI (exclusively investigated in the second year), all remaining treatments were tested in both experimental years. The height of NH3 emissions from INC treatment (12-23 % of applied NH4+-N) was more weather-dependent than those from INJ treatment (12-15 % of applied NH4+-N). In mean over both years, cumulative N2O emission from INJ treatment (13.8 kg N2O-N ha-1 yr-1), was significantly higher than from CON, MIN, and INC which recorded 2.8, 4.7, and 4.4 kg N2O-N ha-1 yr-1. NIs decreased the fertilization-induced N2O emissions from injection by 36 % (mean over all NIs and years) by an order of magnitude comparable to slurry incorporation. The NIs investigated tended to be categorized in inhibitors with prior and delayed inhibitory maximum. Whether low persistence, or poor biological degradability was an advantage, depended on environmental conditions. A combination of two NIs, one with putative prior and one with delayed release behavior reached the highest N2O reduction. In the additional INC treatment, this NI combination tended to reduce annual N2O release by 20 % in comparison to incorporation without inhibitor. Beside the potential of reducing fertilization-induced N2O emissions, NIs might also help to improve CH4 budgets in silage maize production. In general, CON, MIN and INC were net CH4 sinks in both years with mean uptakes of 460, 127, and 793 g CH4-C ha-1 yr-1, respectively. Conversely, slurry injection resulted in net CH4 emissions of 3144 g CH4-C ha-1 yr-1 (mean over both years). However, NIs tended to reduce CH4 emissions from injection by around 48 % and increased CH4 consumption from slurry incorporation by 20 %. Across all treatments and years, direct N2O emissions were the major contributor to total GHG balance. Yield-related GHG budgets from both years were lowest for CON, followed by INC or MIN treatment and significantly highest for sole slurry injection. NIs decreased fertilization-induced GHG release from injection in mean over both years by order of magnitude comparable with slurry incorporation. Consequently, alongside slurry incorporation and broadcast mineral fertilization, slurry injection combined with recommended NIs was evaluated as an equally appropriate fertilization strategy in terms of the atmospheric burden for livestock farmers.
Gesamtbetriebliche Analyse von Weidebetrieben und Weidesystemen in der Milchviehhaltung in unterschiedlichen Regionen Süddeutschlands
(2014) Kiefer, Lukas Robert; Bahrs, Enno
Grassland use and particularly pasture milk production is considered a highly sustainable milk production method which renders many ecosystem services for society (such as greater biodiversity, maintenance of rural cultural regions, climate protection due to higher carbon storage capacity of grassland, better animal appropriateness by regular grazing) as opposed to permanent indoor housing with its high portion of concentrate feed. Nevertheless, the share of pasture farming in overall milk production falls behind production by increasing permanent indoor housing in Germany. Therefore, it appears appropriate to analyze the necessary business environment for pasture farming with consideration of selected ecosystem services actually provided and to sketch suitable recommendations for consultation of farmers. Against this background, the research project “Business analysis and optimization of pasture-based farms and pasture systems in dairy farming in different regions of South Germany” was designed. The research project evaluated production technology, labor economics, business success, greenhouse gas emissions and specific ecosystem services of more than 80 specialized pasture milk producers through three economic years (2008/09-2010/11) and was dedicated to analysing economic and ecological competitiveness of pasture milk production at specific locations. As a result the most profitable pasture farms of the sample regarding management income and hourly rate can compete with the most profitable farms that practice permanent indoor housing; thus, they demonstrate potential economic strength of pasture farms at suitable locations. Decisive determinants of economically successful pasture management include organic farming (higher milk prices and financial compensation), high amounts of milk from forage, sufficient milk yield of the individual cow (>6,000 kg), and a great portion of pasture grass in the feed as well as high work efficiency via seasonal calving, all-day grazing and short-lawn pasture. High profitability and low greenhouse gas emissions can be achieved simultaneously through high efficiency of production. Some farms can even make “greenhouse gas avoidance gains” when production costs and proportionate emissions decrease at the same time thanks to reduced feed demand per kg milk. There is still a substantial need for research in the field of greenhouse gas balancing, particularly regarding evaluation of the manifold ecosystem services of pasture milk production. Many pasture-based farms are compensated for the above-mentioned services via the 2nd pillar of Common Agricultural Policy, but such services remain unconsidered in greenhouse gas balancing so far. It is for this reason that pasture-based farms with low productivity as well as organic farms perform poorly compared to more intensive farming with high productivity if they are measured by the established formulas of greenhouse gas balancing. Consideration of ecosystem services in the framework of greenhouse gas balancing would be possible via economic allocation of emissions between milk, meat, and subsidies of the 2nd pillar of Common Agricultural Policy, however. Based on our sample, this approach would result in an approximation of the carbon footprints per kg milk produced by extensive and intensive or organic and conventional farms, respectively. Nevertheless, a fundamental antagonism still persists between high production efficiency, which is desirable from the point of view of climate protection on the one hand and ecosystem services attainable by extensive production on the other hand. Like other milk production systems, profitable pasture milk production associated with lowest possible greenhouse gas emissions requires first of all competent training and consultation of farmers, which meets the requirements of the respective production method. Policy could improve the relevant framework conditions. Successful pasture milk producers are margin optimizers whose economic success depends above all on higher producer prices (organic milk, pasture milk), cost minimizing milk production based on pasture as the cheapest feed for many farms as well as funding of the ecosystem services which are desired by society. Farm growth and increases in milk yield are harder to achieve for pasture milk producers because consolidated areas are missing or more concentrate feed would be necessary. According to the results of the investigated sample, stronger support of the unique image of pasture milk (which does not necessarily mean monetary funding in this context) as well as increased know-how in the field of pasture milk production is desirable in order to establish or develop the numerous very positive approaches of pasture use in grassland regions that were analyzed in our investigation. The latest EU agrarian reform as well as new EAFRD regulations offer some good starting points in this regard.