Comparative analysis of conventional and organic farming systems: Nitrogen surpluses and nitrogen losses

Nutrient management is a key factor for both economic viability and environmental performance of farming systems. On 32 representative conventional and organic farms in Northern Germany, nutrient management was analyzed in the interdisciplinary monitoring project “COMPASS”. Organic farms had significantly lower nitrogen (N) surpluses compared with conventional farms. The majority of organic farms had very low or even negative N surpluses, indicating insufficient N supply in the cropping system. Nitrogen leaching, however, was too high in many cases on both conventional and organic farms. Strategies for a more targeted nutrient supply in organic farming need to be developed and implemented

Impact of organic agriculture on diversity and abundance of farmland birds in an arable landscape with hedges

A comparative study of breeding bird communities of organically and conventionally cultivated arable fields was carried out in northern Germany in 2005. The research was conducted on 40 pairs of fields (conventional/organic), which were selected with regard to similar field sizes and comparable boundary structures (particularly presence of hedges). Bird communities were solely dominated by the skylark Alauda arvensis L., which was the only frequent species on the tested pairs of fields. Diversity of farmland birds (number of species, Shannon-Index) was not affected by type of management. However, the abundance of skylarks (territories/10 ha) was significantly higher in organic than in conventional fields. As the study will be continued, the one-year findings will be verified with respect to changes of crops in rotations

Untersuchungen zum Einsatz von Pflanzenstärkungsmitteln im ökologischen Futtererbsenanbau

There is a great requirement for cultivation of grain legumes (e.g. peas) in organic farming systems (protein supply for animals, biological nitrogen fixation, previous crop effects). The occurrence of pests and diseases, e.g. Acyrthosiphon pisum, leads to strong yield losses and yield fluctuations. In organic farming systems the use of plant protection products is strongly limited. Plant strengthening products are compatible to this kind of land use and enhance the resistance of plants to harmful organisms. Field trials with some selected plant strengthening products achieve small yield growth under North-German site and climatic conditions, but rarely it is possible to produce statistical evidence. At low up to medium level of disease attack they show good results, meanwhile strong disease attacks lead to unsatisfied results

Futterqualität, Vorfruchtleistung und Nitratauswaschung von über Winter beweideten Kleegrasbeständen

In comparison to harvesting, grazing is less cost intensive. For economical reasons an extended duration of grazing period is recommended. Grazing during winter can cause pasture damages, which is of minor relevance for older grass clover grown on arable land, which will be ploughed in the following spring. Against this background yield and forage quality of 3 different legume species, i.e. white clover, red clover and alfalfa, grown in binary mixtures with two grass species, perennial ryegrass and tall fescue, respectively, were examined before grazing the third growth in autumn or winter. Nitrate leaching losses during winter and yield of the following spring wheat were recorded. Yield and forage quality of the total sward was not significantly influenced by grass species while the interaction of legume species and grazing date had a high impact on yield and quality of the swards. Before grazing in October, swards with white clover showed lower yields and through lower legume contents also lower crude protein concentrations compared to swards with alfalfa or red clover. Losses of leave material led to losses of crude protein concentration in swards with alfalfa or red clover as well as high losses of energy content in swards with alfalfa, which at the latest grazing date were significantly lower than in sward with white clover. Mulching the last growth and autumn grazing led to higher nitrate losses than late winter grazing. After ploughing, no effect of clover grass management on spring wheat yields was observed. Grazing in January led to higher grain crude protein contents in spring wheat than autumn gazing or cutting of the last growth for silage

Brutplatzqualität unterschiedlich ökologisch bewirtschafteter Ackerfrüchte für die Feldlerche (Alauda arvensis)

Habitat quality of different arable crops for skylarks (Alauda arvensis) was analysed in a three year field study on 12 organic farms in northern Germany. Grass clover, spiked spring cereals (barley/spelt/wheat), winter wheat as well as grain legumes (including mixtures) hold constant abundances of skylarks during the whole breeding period. In spring oats, winter spelt and winter cereals with awn (barley/rye), however, skylark densities decreased during the breeding time, which might be explained by comparatively taller and/or denser vegetation structure of theses crops during June/July. Crops showed no significant differences in maximum abundances of skylarks. Concerning possible effects on breeding success, harrowing and/or hoeing of cereals and grain legumes should be completed as early as possible in spring to prevent breeding losses. Compared to cereals and grain legumes, the management of grass clover crops probably resulted in higher breeding losses due to a high intensity of mowing. While the cutting regime of grass clover used as green manure crops can be adapted to breeding phenology of skylarks, modification of cutting systems of forage crops should cause negative effects on quality of forage

Beisaat von Zwischenfrüchten als Möglichkeit zur Reduzierung der N-Auswaschung in Wintergetreide?

In a field experiment the potential of mixtures of winter cereals and catch crops to reduce nitrate leaching was investigated. Pure winter wheat showed the highest N-losses (56 kg N ha-1). Compared to a control without a catch crop, winter rye and oilseed radish grown in pure stand or in mixture with a winter cereal reduced nitrate-leaching by 30 to 80 %. However, common vetch had a significant lower potential compared to the tested non-legume catch crops. Further investigations are needed to optimize the system with special regards to the concurrence between cereal and catch crop in autumn and in early spring

N-Bilanzen ökologischer und konventioneller Praxisbetriebe in Norddeutsch-land – Ergebnisse aus dem Projekt COMPASS

Nutrient balances are important agri-environmental indicators, which describe the magnitude of potential nutrient losses from farming systems to the environment. In order to analyze production systems at the entire farm scale, nitrogen balances and other agri-environmental indicators were assessed on 32 organic and conventional farms in Northern Germany. On organic farms, nitrogen fixation of legumes was determined on representative fields. Irrespective of the specialization (all-arable farms, dairy farms), nitrogen surpluses were always pronouncedly lower on organic farms compared to conventional farms. Organic farms generally conducted a sustainable nutrient management. However, the total nitrogen supply at the farm scale was not sufficient on many organic arable farms

Beitrag einer termingerecht durchgeführten Kainit-Düngung zur Beikrautregulierung in Winterweizen

Due to etching effects on broad leafed weeds, fine ground kainite was used for weed control before synthetic herbicides have become common practice in conventional farming. According to the organic standards kainite can be used as potassium fertiliser. The present study investigates optimal growing stages for application in organic winter wheat and the range of effectiveness. Kainite was applied at a rate of 800 kg per hectare alternatively at EC 29 and EC 30 under the conditions of morning dew on days with high sunshine duration. At both growing stages kainite application reduced the population of hairy vetch, chamomile, cornflower, field pansy, winter rape, common chickweed and persian speedwell. Application at early growing stages led to a higher weed reduction

Zum Einfluss von Standort und Sorte auf Ertrag, Sortierung und Qualität von ökologisch erzeugten Kartoffeln für die Verarbeitung zu Chips

Previous experiments (2000-2001) suggested a strong impact of the site on which organic potatoes are cultivated on the quality of tubers for processing to crisps. In 2003 and 2004, six varieties were selected to be examined consequently on three different sites. Total and graded yield was affected by variety and site. Dry matter content of all varieties was on each site above the required level of 235 %. Reducing sugar content of tubers after harvest was very low and crisps quality very high, only after a storage period varieties could be differentiated. Cautious recommendations of varieties for organic crisp production are given in the paper

Plants for health - primary production of plants containing bioactive compounds that hold a preventive effect towards diabetes II

Ecologically grown medicinal plants containing bioactive compounds hold great potential as high-value niche crops for farmers. However, the way to grow these plants differs from traditional crops. Growing techniques, harvest methods and post-harvest handling of the raw material plays a crucial role regarding the quality of the raw material that the farmers can offer. The purpose of a new research project financed by EU-Interreg IIIA programme is among other things to carry out production, harvest and processing experiments with plants containing bioactive plant compounds that hold a preventive effect towards diabetes II. One of the project’s goals is to draw up cultivation instructions for the primary producers to use when cultivating the plants in question. Examples of the plants that are being examined in the project are Goat’s Rue (Galega officinalis) and Fenugreek (Trigonelle foenum-graecum