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Olika grödors känslighet för packningsgraden i matjorden: två försök med vallväxter 1971-74

Håkansson, Inge


Extensive research work on soil compaction problems has been conducted in Sweden for more than 10 years (Eriksson, Håkansson & Danfors 1974). Within this program a small series of compaction experiments with forage crops was started in 1970. The experiments were laid out on ploughed fields and the crops were sown in the summer (late June to late July) without a cover crop. The experiments included four crops (red clover, timothy, meadow fescue and a mixture of these) and four compaction treatments (no compaation, light, normal and intensive comp) in a split-plot design. The compaction treatments were carried out in connection with the seedbed preparation by driving over the plots with different intensities with tractors of different weights and with different inflation pressures in the tires. Soon afterwards the "degree of compaatness", D, produced in the plough layer by the different treatments was determined. (D = 100 • Yt/Yt,p, where Yt is the actual bulk density and Yt,p, is the bulk density of the soil in a compacted standard state; ef. Håkansson 1973.) In 1970-1972 five experiments were started in the series. In three of them the establishment Of the crop was too poor beeause of intensive drought after sowing. Only two of the experiments could be followed up and each of them was harvested in two years. Thus, the results are very limited and uncertain. Nevertheless, no new experiments of this kind were started since so many problems had occurred. The two experiments followed up were carried out on loam soils in Central Sweden. In both cases the experimental period was drier than normal. In Fig. 13 p. 9, the total yield of dry matter during the experimental period is shown as a function of the "degree of compactness", D, in the plough layer. The yield is given as a percentage of the yield in the highest yielding treatment. In both experiements the best yield was obtained at a rather high degree of compactness (about 90). This is very similar to the results from experiments with spring-sown small grain cereal crops under corresponding weather conditions (ef. Eriksson, Håkansson & Danfors 1974). Thus, the results show that there are probably not very big differences between the small grain cereals and the forage crops included in the experiments as regards the reaction to the state of compactness in the plough layer. No diffepences between the investigated forage crops as perhaps the optimum degree of compactness have been established. However, the results are uncertain and do not exclude the occurrence of even rather large real differences. In experiments with small grain cereals the optimum degree of compactness has proved to be higher when the vegetation period is dry than when it is wet. Thus, in a region with dry climate the plough layer ought to he comparatively dense, in a region with wet climate it should be comparatively loose. Proably the same applies to the forage crops. There is nothing in the experimetal results that contradicts this assumption


jordbearbetning; vallväxter; packningsgrad; försöksserie; markstruktur

Published in

Rapporter från Jordbearbetningsavdelningen / Lantbrukshögskolan
1976, number: 48
Publisher: Institutionen för markvetenskap, Avdelningen för jordbearbetning

UKÄ Subject classification

Agricultural Science

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