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Titre :	Changes in the arable weed flora of Germany during the last five decades
Type de document :	Extrait d'ouvrage
Auteurs :	Harald Albrecht
Année de publication :	1995
Importance :	p. 41-48
Langues :	Anglais (eng)
Catégories :	[CBNPMP-Thématique] Messicole
Résumé :	A whole string of investigations recently described the changes in the agrestal weed flora of different German regions during the last five decades. The present paper summarizes and evaluates the results of these reports. Most of the publications dealing with the change in the average number of weed species found a decline of between 50 to 90 %. Only on barren soils with a sandy texture, which were formerly characterized by low numbers of weed species, the intensified use of fertilizers occasionally caused a rise in variety. Of 203 species, the development of which was mentioned in at last two publications, 120 decreased in occurence (= 59 %), 58 stayed on a constant level (= 29 %) and 25 species (= 12 %) were found more often. Dicotyledoneous plants, cereal weeds, and indicators for calcerous and acid soils were particularly affected by the decline. Another group of taxa which today show considerably lower frequency in fields than in the middle of the century comprises plants mainly occurring in grassland communities. In contrast, where monocotyledoneous and nitropilic plants as well as root crop weeds are concerned, a constant to increasing tendency was observed. Of the species registered in the present survey, 35 are mentioned in the red data books for the eastern and western part of Germany. 27 of them decreased, 6 showed no significant change and 2 species increased in frequency. The development of the weed flora during the last decades has its roots in farreaching changes in arable farming practice. Modifications in the choice of crops, in rotations, chemical and mechanical weed control, fertilizing, soil management, sowing time and technique, purification of seed and land consolidation are reasons for this process. Due to strong interactions between all these components, it is impossible to reconstruct the influence of every single factor on the change of the agrestal weed flora in Germany during the last decades.
Permalink :	https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=85639

Changes in the arable weed flora of Germany during the last five decades [Extrait d'ouvrage] / Harald Albrecht . - 1995 . - p. 41-48.
Langues : Anglais (eng)

Catégories :	[CBNPMP-Thématique] Messicole
Résumé :	A whole string of investigations recently described the changes in the agrestal weed flora of different German regions during the last five decades. The present paper summarizes and evaluates the results of these reports. Most of the publications dealing with the change in the average number of weed species found a decline of between 50 to 90 %. Only on barren soils with a sandy texture, which were formerly characterized by low numbers of weed species, the intensified use of fertilizers occasionally caused a rise in variety. Of 203 species, the development of which was mentioned in at last two publications, 120 decreased in occurence (= 59 %), 58 stayed on a constant level (= 29 %) and 25 species (= 12 %) were found more often. Dicotyledoneous plants, cereal weeds, and indicators for calcerous and acid soils were particularly affected by the decline. Another group of taxa which today show considerably lower frequency in fields than in the middle of the century comprises plants mainly occurring in grassland communities. In contrast, where monocotyledoneous and nitropilic plants as well as root crop weeds are concerned, a constant to increasing tendency was observed. Of the species registered in the present survey, 35 are mentioned in the red data books for the eastern and western part of Germany. 27 of them decreased, 6 showed no significant change and 2 species increased in frequency. The development of the weed flora during the last decades has its roots in farreaching changes in arable farming practice. Modifications in the choice of crops, in rotations, chemical and mechanical weed control, fertilizing, soil management, sowing time and technique, purification of seed and land consolidation are reasons for this process. Due to strong interactions between all these components, it is impossible to reconstruct the influence of every single factor on the change of the agrestal weed flora in Germany during the last decades.
Permalink :	https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=85639