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- Danfors, Birger
(författare)
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Changes in subsoil porosity caused by heavy vehicles
- 1994
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Ingår i: Soil & Tillage Research. - : Elsevier BV. - 0167-1987 .- 1879-3444. ; 29:2-3, s. 135-144
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Tidskriftsartikel (refereegranskat)abstract
- Previous Swedish studies led to a recommendation to limit the load on a single axle to 6 Mg and on a tandem axle unit to 8 Mg in order to avoid permanent subsoil compaction in wet soil. In recent years large tyres that can carry large loads at low inflation pressure have been available. In a new project it was studied whether the use of such tyres may change the recommended load limits. Loads of 8-12 Mg on a single axle or 10-20 Mg on a tandem axle unit significantly reduced the porosity in the 300-400 and 400-500 mm soil layer. In the 400-500 mm soil layer in inflation pressure of 50 or 100 kPa compared with 150 kPa did not substantially reduce compaction. The results indicate that no important increase in the previously recommended limits can be proposed. © 1994.
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- Danfors, Birger
(författare)
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Equipment for seed placement below a removed and replaced surface tilth
- 1987
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Ingår i: Journal of Agricultural Engineering Research. - : Elsevier BV. - 0021-8634 .- 1095-9246. ; 38:3, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish Institute of Agricultural Engineering (JTI) started the development of a new seeding technique in 1979. The basic ideas are founded on model experiments performed at the Swedish University of Agricultural Sciences. These experiments led to the development of an optimum seedbed where the seed emerged early and evenly, and the weeds met strong competition. The crop grew and ripened uniformly. The early JTI experiments were performed with a small machine with a width of only 1200 mm. Nevertheless, these tests showed that it was possible to sow seed according to the model experiments. The guidelines recommended that the seed should be spread uniformly on a smooth moist surface and be covered with a fine structured soil to act as a vapour barrier. Stones and organic residues should be left on top of the seedbed. In 1984, JTI, in cooperation with AB Överums Bruk, one of the leading manufacturers of agricultural machinery, constructed a new seeder with a working width of 3000 mm. This machine has been tested in field experiments over two years. The most important benefits are the potential to increase the yield and decrease the total energy requirement due to reduced soil tillage and soil compaction. If the yield with the standard technique is around 6 t/ha the results achieved with the presented technique indicates yield increases of at least 5%. The technique also offers means of combating competition from weeds. Finally, the method also offers a solution to the problem of crop residues in connection with seeding. © 1987.
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