| 1. |
- Lindberg, T., et al.
(författare)
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Distribution of15N in the soil-plant system during a four-year field lysimeter study with barley (Hordeum distichum L.) and perennial meadow fescue (Festuca pratensis Huds.)
- 1989
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Ingår i: Plant and Soil. - Dordrecht, Netherlands : Kluwer Academic Publishers. - 0032-079X .- 1573-5036. ; 119:1, s. 25-37
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Tidskriftsartikel (refereegranskat)abstract
- An annual cereal, barley, and a perennial grass ley, meadow fescue, were grown in field lysimeters in Sweden and fertilized with 12 and 20g Ca(NO3)2-N m-2 yr-1, respectively. Isotope-labeled (15N) fertilizer was added during year 1 of the study, whereafter similar amounts of unlabeled N were added during years 2 and 3. The grass ley lysimeters were ploughed after the growing season of year 3 and sown with barley during year 4. The barley harvest in year 1 removed 59% of the added fertilizer N, while the fertilizer N export by two meadow fescue harvests in year 1 was 65%. The labeled N export decreased rapidly after year 1, especially in the barley, but increased slightly after ploughing of the grass ley.The microbial biomass, measured with the chloroform fumigation method, incorporated a maximum of 1.4-1.7% of the labeled N during the first seven weeks after application. Later on, the incorporation stabilized at less than 1% in both cropping systems.The susceptibility of the residual labeled N to mineralization was evaluated three years after application by means of long-term laboratory incubations. The curves of cumulative mineralized N were described by a two-component first-order regression model that differentiated between an available and a more recalcitrant fraction of potentially mineralizable N. There was no difference in the amounts of potentially mineralizable N between the cropping systems. The labeled N comprised 5 and 2% of the amounts of potentially mineralizable N in the available and more recalcitrant fraction, respectively. The mineralization rate constants for the labeled N were almost twice as high as for the total potentially mineralizable N. The available fraction of the total potentially mineralizable N was 12%, while twice that proportion of the labeled N was available.It was concluded that the short-term ley did not differ from the annual crop with respect to the early disposition of the fertilizer N and the behaviour of the residual organic N.
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| 2. |
- Schnürer, Johan, 1957-, et al.
(författare)
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Mineralization of nitrogen from15N labelled fungi, soil microbial biomass and roots and its uptake by barley plants
- 1987
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Ingår i: Plant and Soil. - Dordrecht, Netherlands : Kluwer Academic Publishers. - 0032-079X .- 1573-5036. ; 102:1, s. 71-78
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Tidskriftsartikel (refereegranskat)abstract
- The availability of nitrogen in15N labelled fungi, soil microbial biomass (Ca(15NO3)2 immobilized by addition of glucose), barley roots and Ca(NO3)2 to barley plants was investigated in a greenhouse experiment. Samples of above-ground plant biomass were taken five times during 76 days. During this time, and at the start of the experiment, the C and N contents of the soil microbial biomass were determined. Microbial biomass-C decreased during the first 41 days, and then increased back to pre-treatment levels. Only 2% of the total soil15N was found in the microbial biomass two days after additions of Ca(15NO3)2. At the final sampling 76 days later, 17% of the15N remaining in soil was found in the microbial biomass. In the other tratments, microbial biomass-N accounted for 20% of remaining soil15N in the one that had received fungi, 29% in the one with barley roots and 35% in the Ca(NO3)2 plus glucose treatment. At harvest, 38% of the soil15N at day 0 added as Ca(NO3)2-N, 29% of fungal-N, 10% of N immobilized in the soil microbial biomass and 7% of N in barley roots was recovered in the above-ground plant biomass.It can be concluded that nitrogen in the native soil biomass is resistant to mineralization and plant uptake. The use of laboratory grown organisms for mineralization studies will overestimate the plant availability of nitrogen in soil microorganisms.
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| 3. |
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| 4. |
- 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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| 5. |
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| 6. |
- Gunnarson, S., et al.
(författare)
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Jerusalem artichoke (Helianthus tuberosus L.) for biogas production
- 1985
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Ingår i: Biomass. - : Elsevier BV. - 0144-4565. ; 7:2, s. 85-97
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Tidskriftsartikel (refereegranskat)abstract
- The above-ground growth (stems and foliage) of Jerusalem artichoke (Helianthus tuberosus L.) was studied in field experiments in Sweden during 1981 to 1983, in order to investigate the possibility of producing biogas from biomass. Dry matter yields of three varieties were determined at four different harvesting times. The yields varied between 7 and 16 tons of dry matter per hectare. Anaerobic digestion experiments showed that fresh and ensiled above-ground parts of the plant could produce 480-680 litres biogas per kg organic material. The chemical composition of the plant material was determined before and after digestion. An analysis confirmed that economic biogas production from above-ground parts of Jerusalem artichoke is possible under certain conditions. © 1985.
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| 7. |
- Göransson, L., et al.
(författare)
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Effects of different handling systems on pig feed quality
- 1982
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Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 7:1, s. 11-26
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Tidskriftsartikel (refereegranskat)abstract
- Separation of feed mixtures and its effect on the production traits of growing-finishing pigs was studied in three experiments. In Experiments I and II the effects of different types of equipment to prevent separation in a silo were studied. Experiment III dealt with separation along a feed transport chain. Experiments I and II clearly demonstrated an increase in feed quality variation by filling a silo without any arrangement to reduce separation. The last feed to be extracted from a silo filled in this manner showed an increasing amount of small particles and contents of crude fibre and ash, a decrease in the bulk density and also in the digestibility of nutrients and in the performance of the pigs. Filling a silo equipped with chutes by an auger or pneumatically through a cyclone did not create separation problems, and consequently there were no differences between these treatments in the production experiments. Separation measured by particle size, bulk density or chemical composition was not noticeable along the feed transport chain (Experiment III). There was no effect on performance of the pigs of their location along the chain. © 1982.
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| 8. |
- Kaspersson, A., et al.
(författare)
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Microbial dynamics in barley grain stored under controlled atmosphere
- 1988
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Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 19:4, s. 299-312
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Tidskriftsartikel (refereegranskat)abstract
- Barley of 2 moisture contents, 20-23% and 26-28%, was stored airtight for 2 separate seasons in 2 full-scale silos, and for 3 separate seasons in 12-16 pilot silos (1.25 m3). The microbial dynamics were studied, using colony-forming units (CFU) of microorganisms, the proportion of internally-invaded kernels and ATP content. The ATP content was a good measure of the microbial activity, which decreased after loading and was very low during the winter period. Field-associated moulds and yeasts decreased in numbers of CFU and in the amount of invaded kernels. Fusarium species survived more satisfactorily than most field fungi. The temperature rise in spring caused an increase in ATP content, as a result of extensive growth of yeast of the genera Hansenula and Candida. This activity started earlier in the high-moisture grain (March). In May, a significant increase in CFU of Penicillium was observed and, during May to July, in many silos, all kernels were invaded, mostly by P. roqueforti. In an attempt to increase the time of safe storage, some technical improvements and gaseous and liquid chemical additives were tested. Attachment of "lungs" to the silos, and addition of organic acids or gases (CO2, N2, NH3) to the grain, increased the safe storage time by one to several months. The aerobic storage stability of rolled barley taken in July from the full-scale silos was tested. The rapid deterioration following unloading limited the aerobic storage stability to a few days. © 1988.
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| 9. |
- Krigström, Arne, 1931-
(författare)
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Ar det öppna landskapet hotat?
- 1988
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Ingår i: Kulturminnesvård. - Stockholm : Riksantikvarieämbetet. - 0346-9077. ; :3, s. 7-10
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Avdelningsdirektör Arne Krigström, Statens naturvårdsverk, har vid en diskussion på LRF hållit föredrag på temat: Ar det svenska landskapet hotat? Föredraget bygger på en utredning som utförs av avdelningsdirektör Rune Andersson i naturvårdsverket. Det återges något förkortat och behandlar hotet mot det öppna landskapet i samband med jordbrukets omställning till alternativa grödor och nya odlingsformer.
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| 10. |
- Svensson, Erling, 1943-
(författare)
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En sydsvensk madslåtterbonde
- 1984
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Ingår i: Kulturminnesvård. - Stockholm : Riksantikvarieämbetet. - 0346-9077. ; :5, s. 13-15
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Erling Svensson, natur— och kulturvårdare från Trollhättan, berättar i ord och bilder om våtslåtter i forna dagars Västergötland och presenterar en madslåtterbonde.
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