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| Zaller, Johann G.. |
| Broad-leaved dock (Rumex obtusifolius L., Polygonaceae) is an agronomically important perennial weed causing decreases in pasture yields and fodder quality. Non-chemical control measures for dock are often limited to frequent pulling and cutting, additionally it is usually avoided by grazing animals. Here, the regeneration of R. obtusifolius in a Rumex-infested grassland grazed by a sheep breed that explicitly feeds on dock (Ovis aries L. cv. East Prussian Skudden) was compared to cutting. Therefore, regeneration of 90 R. obtusifolius plants of three different size classes was monitored in three plots during three grazing and cutting cycles. Plant height and number of fruit-stands of regrown R. obtusifolius was significantly lower, number of... |
| Tipo: Journal paper |
Palavras-chave: Crop health; Quality; Protection. |
| Ano: 2006 |
URL: http://orgprints.org/10452/1/Zaller_2006_BICO.pdf |
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| Zaller, Johann G.. |
| In perennial grasslands R. obtusifolius (broad-leaved dock) is often surrounded by certain plant species. Thus, it is hypothesized for the current study that Rumex can affect their neighbouring plant species by allelopathic interactions. To test this hypothesis, in a series of laboratory and field experiments aqueous extracts of green R. obtusifolius leaves were sprayed on seeds of 14 herbaceous plant species (graminoids, non-leguminuous forbs and leguminuous forbs) commonly native to perennial grasslands and its effects on seed germination compared with those with tap water spraying. An allelopathic effect was defined as inhibitory influence of Rumex extracts on seed germination relative to tap water. Generally, results of the laboratory experiments... |
| Tipo: Journal paper |
Palavras-chave: Crop health; Quality; Protection. |
| Ano: 2006 |
URL: http://orgprints.org/10454/1/Zaller_2004_JPDP.pdf |
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| Zaller, Johann G.. |
| Understanding the competitive ability of Rumex obtusifolius against grassland species is essential for developing efficient control strategies against docks. Here we present results from a greenhouse experiment where we tested shoot and root competition between Rumex regenerating from rhizome fragments and grassland species (grasses, herbaceous and leguminous species). Competitive ability was expressed as the relative above- and belowground biomass partitioning and, concentrations and allocation of carbon and nitrogen of the plant species studied. Regeneration of Rumex was significantly affected by competition through neighbouring native grassland species. Rumex responded to concurrent shoot and root competition of grassland species with 50% more... |
| Tipo: Journal paper |
Palavras-chave: Crop health; Quality; Protection. |
| Ano: 2004 |
URL: http://orgprints.org/10453/1/Zaller_2004_JPDP.pdf |
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| Zaller, Johann G.; Köpke, Ulrich. |
| We studied the effects of applications of traditionally composted farmyard manure (FYM) and two types of biodynamically composted FYM over 9 years on soil chemical properties, microbial biomass and respiration, dehydrogenase and saccharase activities, decomposition rates and root production under grass-clover, activity and biomass of earthworms under wheat, and yields in a grass-clover, potatoes, winter wheat, field beans, spring wheat, winter rye crop rotation. The experiment was conducted near Bonn, on a Fluvisol using a randomised complete block design (n=6). Our results showed that plots which received either prepared or non-prepared FYM (30 Mg ha−1 year−1) had significantly increased soil pH, P and K concentrations, microbial biomass, dehydrogenase... |
| Tipo: Journal paper |
Palavras-chave: Composting and manuring. |
| Ano: 2004 |
URL: http://orgprints.org/10455/1/Zaller%26Koepke_2004.pdf |
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| Zaller, Johann G.; Saxler, N.. |
| Earthworms are suggested to play an important role for the plant diversity of grassland ecosystems. Here we tested, whether (i) Lumbricus terrestris L. selectively feeds on seeds of grassland species, (ii) feeding patterns match with seed species present in surface casts in a permanent grassland and (iii) grassland plant seeds in different soil depths are relocated by the activity of earthworms. Food choice experiments with 10 plant species (3 grass spp., 4 non-leguminous herb spp., 3 leguminous spp.) showed that earthworms significantly selected between the offered seeds and generally favoured herbaceous species over grass species. Seed species in grassland surface casts did not correlate with seed species preferred by earthworms in the feeding... |
| Tipo: Journal paper |
Palavras-chave: Biodiversity and ecosystem services. |
| Ano: 2007 |
URL: http://orgprints.org/18270/1/Zaller_Saxler_2007EJSOBI.pdf |
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