Vergleich der Klimarelevanz ökologischer und konventioneller Landbewirtschaftung

Die Charakterisierung der mit den Begriffen "Ökologischer" und "Konventioneller" Landbau bezeichneten Wirtschaftsweise bleibt ebenso wie der Vergleich dieser landwirtschaftlichen Produktionssysteme auf den für die Studie notwendigen Rahmen begrenzt. Emissions- und Senken- Potentiale von klimarelevanten Gasen im Agrarsektor werden im Systemvergleich erarbeitet. Die aktuellen Ergebnisse der beteiligten Studiennehmer innerhalb des Studienprogramms "Landwirtschaft" der Enquetekommission zu den landwirtschaftlichen Emissionen von klimarelevanten Gasen konnten leider nicht in diese Studie eingearbeitet werden, da sie zeitgleich erstellt wurden. Zwar ist der Anteil des Agrarsektors am nationalen Gesamtenergieverbrauch in den Industrieländern nur gering, aber der Energieeinsatz ist für den Primärsektor Landwirtschaft von grundsätzlicher Bedeutung und bildet auch vor dem Hintergrund der aktuellen agrarpolitischen Diskussion zu nachwachsenden Energieträgern einen weiteren Schwerpunkt dieser Studie. Die Nutzungspotentiale regenerativer Energieressourcen sind in den beiden betrachteten Produktionssystemen in unterschiedlichem Maße realisierbar. Die Restriktionen im Ökologischen Landbau ebenso wie die daraus ableitbaren Konsequenzen für die künftige Ausrichtung der Flächennutzung werden dargelegt. Die systembedingt unterschiedlichen Anpassungspotentiale an den prognostizierten Klimawandel können mangels regionaler Auflösung der Vorhersagen und ungenügendem Grundlagenwissen nur angedeutet werden. Von grundsätzlicher Bedeutung ist die "Streßsituation" von Agrarökosystemen bei sich ändernden Umwelt- und Klimaverhältnissen. Die Darstellung unterschiedlicher Wirkungen von Anbausystemen des Konventionellen und des Ökologischen Landbaus wird schwerpunktmäßig für die BR Deutschland bzw. Nordwesteuropa vorgenommen. Ergebnisse eines Vergleichs dieser Agrarsysteme in Entwicklungsländern (Agroforstsysteme, Monokulturen von Export-cash-crops) können im Rahmen dieser Studie nur angedeutet werden. Konsumenten ökologisch produzierter Lebensmittel zeigen in ihrem Kaufverhalten differenzierte Verbrauchspräferenzen. Ein verändertes Nachfrageverhalten hat für den Vergleich verschiedener Anbausysteme eine entscheidende Bedeutung. Ebenso sind bei der gesamthaften vergleichenden Betrachtung von unterschiedlichen landwirtschaftlichen Produktionssystemen u.a. der Energieaufwand für verschiedene Vermarktungswege (Ferntransport, Erfassungsaufwand, Produktionsstättendichte etc.) und Verarbeitungs¬formen mit einzubeziehen. Diese Schnittstelle zwischen landwirtschaftlicher Erzeugung und dem Konsum von Lebensmitteln ist Inhalt der Folgestudie "Landwirtschaft und Ernährung" innerhalb des Studienprogramms "Landwirtschaft" der Enquete-Kommission "Schutz der Erdatmosphäre". Schwerpunkt der vorliegenden Studie bildet deshalb die landwirtschaftliche Produktion selbst

Organic Pilot Farms in North Rhine-Westphalia (Germany)

Since 1993, research, advisory service and practice work together in the German Federal State of North Rhine-Westphalia (NRW) on solutions for selected issues of plant cultivation and animal husbandry with practical relevance for organic farmers. The project that is funded by NRW and the European Union entails demonstration and optimisation of selected organically operating farms and their methods of production as well as professional advice. The project is coordinated by the Institute of Organic Agriculture and executed in cooperation with the Chamber of Agriculture and contributes effectively to the expansion of Organic Agriculture (OA) in NRW. In this successful participatory and interdisciplinary cooperation between practice, extension service and research, 30 farms that are distributed all over NRW and integrate a wide range of different types of production in their typical local region are involved in developing the research questions, executing experiments and discussing results. Solutions are assessed and optimised on farm level and demonstrated in the practice of major farms in order to secure the knowledge transfer in extended agricultural practice. The feasibility of the methods is immediately assessed by practitioners and transmitted to colleagues

Nutrient cycle on organic farms: stall balance of a suckler herd and beef bulls

In organic agriculture, the internal farm nutrient cycle must be quantified to ensure high system productivity along with environmentally sound production processes. In contrast to common farmgate and field balances, budgeting at the stable level is seldom undertaken. When budgeting mixed farming systems, a substantial lack of nutrients can be detected in the nutrient flow chain "forage and straw input - stable - manure output". Therefore, stable balances focus on a central component of whole farm nutrient budgets for developing efficient nutrient management strategies. At the experimental farm for organic agriculture Wiesengut in Hennef, Germany, all solid mass flows for a suckler herd and a herd of beef bulls were measured. Relative balance values obtained for dry matter and C (45 to 56%), N (16 to 36%), P (-7 to 22.5%), K (0 to 13%) and ash (-4 to 7%) showed a wide range. Balances are very sensitive to variations in mass flow and nutrient content for components with high nutrient contents and/or a large contribution to total mass flow (e.g. manure, silage). In developing strategies to minimize N losses, by reducing N surplus in the ration, it has to be considered, that in contrast to dairy farms, a suckler herd for beef production integrated in an organic farm has to adapt to crop production demands. from: HAAS, G., B. CASPARI, U. KÖPKE 2002: Nutrient cycle on organic farms: stall balance of a suckler herd and beef bulls. Nutrient Cycling in Agroecosystems 64, 225-230

Farm gate nutrient balances of organic dairy farms at different intensity levels in Germany

Organic farms are characterized as low external input agro-ecosystems. Currently, some organic dairy farmers feed higher amounts of concentrates and succulent feed, some of which is purchased, to increase the dairy performance of their cows. To assess the environ¬mental impact of this practice, nutrient balances at the farm-gate level of 26 organic dairy farms located in two different regions in Germany were compiled and analysed. The farms are characterised by different production features and feeding intensity levels (0 - 2.72 t DM of concentrates per cow and year, which was 0 - 378 g kg-1 milk) yielding 5,150 - 8,790 kg milk on average per cow and year. The area- and product- (milk) related farm-gate nutrient budgets for P and K are almost balanced (mean -3 kg P ha-1, range (R): -14 to 4 kg P ha-1; -0.5 g P kg-1 milk, R: -2.8 to 0.9 g P kg-1 milk and 1 kg K ha-1, R: -13 to 15 kg K ha-1; 0.1 g K kg-1 milk, R: -2.4 to 3.9 g K kg-1 milk). The N surplus averages only 43 kg ha-1 (R: 8 to 85 kg N ha-1) and 8.2 g kg-1 milk (R: 2.1 to 17.1 g kg-1 milk), but the correlation between the amount of feed purchased on a net basis and N surplus is significant (r = 0.56, p = 0.003). Average area-related nutrient use efficiency for all farms calculated as the proportion of input to output is high for N (45%), P (164%) and K (91%). The share of nutrient input and output components and correlations between parameters are presented. To classify the results, investigations comparing organic and conventional dairy farming in Europe are listed, indicating an N surplus for organic farms, which is often only half or a third of the surplus of conventional farms. However, intensification in organic dairy farming has, in some cases, significant impacts that need to be assessed to determine its environmental performance and profile

Weed Control with Straw Residues in Occasional Direct Seeding of Faba Bean (Vicia faba sp.) in Organic Agriculture

In order to gain momentum in the consolidation process of no-tillage systems in Europe’s Organic Agriculture, occasional direct seeding (DS) of faba bean (FAB) into a mulch layer of residues from precrop oats should be scrutinized. In contrast to non-legumes, grain legumes do not depend on soil-borne nitrogen due to their ability to fix nitrogen symbiotically. Concerning weed infestation, straw residues left by precrops may at least physically suppress weeds. In order to prove this hypothesis, two field experiments were carried out in 2009 at two sites in the lower Rhineland region, Germany. DS treatments were combined with 0, 4, and 6 t ha-1 of straw residues. Mouldboard ploughing (MP) combined with conventional seedbed preparation was used as control. Compared to the DS treatment without straw residue (0 t ha-1), DS treatments with straw residues (4 and 6 t ha-1, resp.) resulted in significantly lower weed density (70 and 84 % resp.). Neither differences were observed in both shoot dry matter of FAB and weeds for DS with straw residues compared with MP, nor for the grain yields of FAB. We conclude that occasional DS of FAB in OA is successful to reduce annual weeds sufficiently and may not lead to reduced FAB yields

Yield and quality of potato tubers: Effects of different intensity and kind of manuring (biodynamic or organic)

Biodynamic farming is the oldest organic farming movement in Germany. Since Dr. Rudolf Steiner’s “Course on Agriculture” held in 1924, the number of biodynamic farmers in Germany has grown continuously, with 1,317 farmers currently producing on 47,592 ha. One of the most distinctive aspects of biodynamic farming is the use of the so-called biodynamic preparations, which are applied in homeopathic doses. Biodynamic preparations are supposed to improve plant growth and food quality, minimising natural variations. This paper deals with investigations of influences of these preparations and increased manure application on potato yield and tuber quality. The results are drawn from extensive research on organic potato production carried out by several institutes of the University of Bonn, sponsored by the Deutsche Forschungsgemeinschaft (Bonn), and the Eden Foundation (Bad Soden)

Possibilities and limits of reduced primary tillage in organic farming

In two organically cultivated field trials, located in Germany and Greece, effects of reduced primary tillage systems on root and shoot growth of cereals were investigated. The field trial in Rommersheim near Mainz, Germany, was established in 1994 by the foundation „Stiftung Ökologie und Landbau“. The Agricultural University of Athens established in 1995 a similar experiment in a field trial carried out by The Laboratory of Crop Science, located in Athens, Greece

Ökobilanz integrierter und ökologischer Apfelerzeugung in Hamburg

In 1997-1999 a life-cycle assessment of organic-extensive, organic-intensive and integrated apple production in Hamburg was carried out. The investigation was based on an analysis of 7 organic and 7 integrated farms in Hamburg and the surrounding area. The life-cycle assessment included 12 impact categories. The functional unit (1 kg apple or 1 ha farm land) differed depending on the impact categories. Compared to integrated production, organic production gave advantages in the impact categories ecotoxicity, human toxicity, drinking water protection, biodiversity and landscape image, whereas integrated production showed better results in the environmental effects that are caused by energy use. The investigation revealed potential for optimisation of organic production concerning the biotope structure, the use of copper preparations and especially the use of energy and machinery

Competitiveness of winter wheat stands against weeds: Effects of cultivar choice, row width and drilling direction

The need for competitive crop stands can be regarded as a basic requirement for weed control, potentially reducing the need for direct control measures. One way the crop may suppress weed growth is by the restriction of light through crop shading. As part of the EU-project ²Strategies of weed control in Organic Farming² (WECOF) trials with winter wheat were carried out to evaluate the potential of wheat shading ability as a weed control measure. Factors included were cultivar, row width and drilling direction. Results of the first experimental year are presented

Environmental Impacts and Economic Differences in grassland based Organic Dairy Farms in Germany – Modelling the Extremes

Differences in environmental impact and economic returns between intensive and low-input organic dairy production are investigated using two simplified model farms with different amounts of concentrates being fed. In four scenarios, ecological and economic effects of restricting the more intensive farm management practice beyond the existing regulations of organic farming are analysed. In the initial situation, the intensive farm has a financial advantage of about 600.00 € per ha compared with the low-input farm, while the environmental risks caused by its production system are higher in several Life Cycle Assessment (LCA) categories. We showed for the model case that limiting livestock density and using regional grown concentrates bring about considerable improvements in LCA results, while restricting the amount of concentrates used does not. These three scenarios result in economic deterioration for the intensive farm. A fourth scenario increasing the share of pasture in daily dry matter intake (DMI) to a minimum of 50% during the grazing season has positive effects environmentally as well as economically