Newsletter from Danish Research Centre for Organic Farming • December 2004 • No 4

Feeding with lupines reduces the amount of skatole in organic pigs

Female and castrate organic pigs fed with 25 pct. lupines had significantly lower skatole concentrations in backfat compared with the control treatments without lupines. The effect of lupines was probably independent of the other food components and it is expected the skatole concentration could be decreased by ca. 50 pct. also in entire male pigs fed with lupine, thereby reducing the number of entire male pigs with boar taint.
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Landscape and nature quality in the development and profiling of organic farming

Organic agriculture has potential for making a special contribution towards nature and landscape. And the farmer plays an important part as decision maker. A qualitative interview study show that the farmer’s production strategy often has an impact on how he acts in relation to nature. At the same time it is difficult for the individual farmer to express concrete expectations of nature quality. Read the article

Nitrogen and weeds determine crop yields in arable organic crop rotations

Crop yields in the organic arable crop rotation experiments have mainly been limited by nitrogen supply and by competition from weeds. In spring barley, weeds have in several years reduced yields just as much as yields have been raised by manure application. The use of catch crops in a rotation with grass-clover had a very limited effect on yield at the crop rotation level. Read the article

Spread of salmonella bacteria in organic pigs

Experiments have shown a possible transfer of salmonella bacteria from infected organic pigs to non-infected pigs kept on outdoor pastures. Furthermore, salmonella can survive in the pasture environment and infect new pigs under certain circumstances. An unexpected variety of salmonella types were found in both pigs and the environment during the experiment. Read the article

Common Couch-grass control with less tillage

Control of Common Couch-grass often conflicts with the need to retain nutrients in organic cropping systems, as it involves intensive tillage in the post-harvest period. Thus, preferably the soil should be cropped through the entire year to prevent nutrient leaching from the root zone. Research has shown that new control strategies may combine the reduction of couch infestations and a soil cover with plants during the post-harvest period. This may have potential for practical implementation. Read the article

Simulating crop production and nitrate leaching losses from organic arable crop production

The dynamic FASSET model adequately simulated the crop yield and N-leaching in a 4-crop rotation experiment at three different locations. Scenario analyses showed that crop yields increased and N-leaching decreased by use of catch crops and/or by use of grass-clover for biogas rather than as a green manure, assuming that the digested slurry was returned to the cereal crops. Difference in the responses of crop management between the three sites demonstrated that specific soil and climate conditions should be accounted for in the design of cropping systems. Read the article

Grazing and nitrogen fertilisation increases nitrous oxide emissions from grasslands

Modelling of nitrous oxide emissions from agricultural systems shows that estimates based solely on fertilizer use are too simple. There are large differences between soil types in the emissions, and the proportion of fertiliser nitrogen emitted as nitrous oxide is smaller at lower nitrogen rates. This indicates that organic farming is an interesting option for reducing greenhouse gas emissions, because the nitrogen input is lower in organic farming.

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Molecular diagnostic methods can prevent unnecessary rejection of organic seed lots

In some years, large amounts of organic seed lots are discarded due to the presence of seed-borne diseases. Sensitive and fast diagnostic methods, based on molecular techniques such as PCR, may be helpful tools to identify specific pathogens and thereby avoid unnecessary rejection of organic seed lots.

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Crop rotation limits Canada thistle, but not Couch-grass or annual weeds

Direct weed control of annual as well as perennial weeds was necessary to reduce the amount of weeds in organic crop rotation experiments at three locations in Denmark. For Canada thistle, however, the rotation was the most important controlling factor: the rotation with grass-clover had less thistle biomass than the one without.

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News briefs

  • Trends and developments in organic livestock farming systems.
  • Webpage on Mediterranean long-term crop rotations.
  • Successful congress on Organic Farming, Food Quality and Health.
  • SAFO workshop.

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