Abstract

Soil structure was studied in long-term trials with different cropping systems, which are run by the Rural Economy and Agricultural Society in Kristianstad. The field trials have been going on since 1987 and are located to three experimental sites in Skåne. The investigation of soil structure was concentrated to the experimental site Bollerup, but some measurements were also made at the experimental site Önnestad. At the experimental site Östra Ljungby, however, no measurements were made due to lack of time. A conventional and an organic cropping system were included in the study, both without livestock. The trial was designed as a plot trial, where each crop in the two rotations was grown every year. In Bollerup , the experimental plots were not randomly arranged, whereas in Önnestad they were arranged so that the different treatments were evenly distributed in the experimental field. There were no replications. In order to get a complete picture of the soil structure in both cropping systems, several physical and biological properties were investigated. These were aggregate strength, hydraulic conductivity, penetration resistance, the amount of roots and the amount of earthworms. In Bollerup all of these properties were measured, whereas only penetration resistance and the amount of roots were measured in Önnestad. The aim of the study was to answer the question: Do conventional and organic cropping systems have different effects on soil structure? When measuring aggregate strength, the content of clay and organic material in the topsoil was also measured. The conventional part of the experimental field had considerably higher contents of clay and organic material than the organic part due to a textural gradient in the field. The aggregate strength was slightly higher in the conventional cropping system than in the organic one. The hydraulic conductivity in the subsoil was considerably higher in the conventional cropping system than in the organic one. This difference was due to the fact that there was a textural gradient also in the subsoil. The conventional cropping system had a subsoil of coarser texture. The penetration resistance did not differ between the cropping systems at any of the experimental sites. The results from the analysis of root length indicated a greater root length in the organic cropping systems in Bollerup as well as Önnestad. At Bollerup, the root length at the level 10 - 15 cm in the organic system was twice that in the conventional system. The same relation applied to Önnestad at the level 30 - 35 cm. The number of earthworms was very low for both systems at Bollerup. The sampling did not reveal any great differences between the systems considering either the number of worms per m2 or the biomass per m2 . The same four species were found in both systems. No general difference between the cropping systems considering their effect on soil structure could be proved. The arrangement of the experimental plots at Bollerup was inexpedient. The textural gradient in both topsoil and subsoil has affected not only the properties that were analyzed in this stud y, but has in all probability also affected prior studies in the field trial. This makes it impossible to compare the two cropping systems. However, the systems can still be studied separately by repeated measurements during a longer period of time

Keywords

jordbearbetning; markstruktur; odlingssystem; fältförsök; konventionell odling; ekologisk odling; markfysikaliska undersökningar; markbiologiska undersökningar

Published in

Meddelanden från Jordbearbetningsavdelningen
2003, number: 42
Publisher: Institutionen för markvetenskap, Avdelningen för jordbearbetning, Sveriges lantbruksuniversitet

UKÄ Subject classification

Agricultural Science
Environmental Sciences related to Agriculture and Land-use

Permanent link to this page (URI)

https://res.slu.se/id/publ/31095