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Seed, germination and site characteristics: which parameters of arable weeds do explain the change of frequency in Germany?
Summary
For 130 arable weed species occurring in Germany we analysed their combinations of seed, germination and habitat traits by means of Principal Components Analyses. Special attention was paid to species with presently de- or increasing populations. Results did not yield any indication that advantageous strategies like, e. g. a rapid and complete germination of seeds, have a beneficial effect on the present situation of the weed species. Germination rates and the time span needed to reach the peak of germination showed little differentiation between species. Thus, these germination traits are not well suited to explain the success or failure of species. Presently expanding weed species (high ‘tendency of change’-value according to ELLENBERG et al. 1992) were characterised by high optima and wide amplitudes in germination temperature, and high Ellenberg nutrient values.
In general, the tendency of change for arable weeds showed higher correlations with habitat traits (expressed as Ellenberg indicator values) than with seed and germination traits. Expanding species were characterised by high nutrient values, high moisture values and low light values. Remarkably, many species with this combination of traits are considered introduced species in Germany (neophytes). Arable weed species may also profit from modern agronomy with its constant adaptations of cultivation and harvesting practices, which create favourable new site conditions for contemporary crop species. However, our results show that mainly neophytes benefit from modern agriculture, and not the native arable weeds.
Rewarding weeds in arable farming – traits, goals and concepts
Summary
From an agrarian perspective the occurrence of weeds on arable land is predominantly associated with negative side effects: competition for light and nutrients, hampering of the harvest, or reduction of crop quality. On the other hand weeds can also be associated with quite a number of positive side effects. They can contribute to the conservation of abiotic resources and promote beneficial insects. Beside of their ecological values weeds also gain growing importance as genetic resources for the breeding of economic plants. Furthermore, due to an exceptional flowering aspect weeds possess special scenicaesthetical values. Thus, despite of their harmful short and long term effects on crops, there is reason to maintain weed species diversity. Currently arable weeds do not gain much attention in agri-evironmental schemes in Germany. Most conservation concepts have a local, mainly museal character. The success of conservation measures is determined by factors of economic-ecological efficiency, practicability and acceptance. A result-oriented rewarding of arable weeds promises improvements of all three factors. However, it is a critical trait of arable weeds to be simultaneously objective of conservation and of control measures, which should be minimised due to their costs, as well as abiotic and biotic side effects.
The Karlstadt position paper for the preservation of arable field plants
Summary
The complete article is written in German
“Protect Scandix, Legousia, Arnoseris and their relatives!” This is the basic message of the position paper, which tries to draw attention to the situation of endangered arable field plants in Germany. Intensive agriculture and the fusion of small fields on the one hand, but also abandonment and afforesting on the other endanger the last sites of colourful arable field species. Neither standard tools of nature conservation (i.e. nature protection areas) nor the European system of Natura 2000 regions do improve the situation. New solutions have to be found to preserve and to develop diverse rural landscapes with their typical arable field flora and fauna. The position paper points out possibilities of protection and makes claims on citizens, experts and politicians. In the appendix the scientific background is shown.
The Karlstadt position paper was written after the conference for the preservation of arable field plants in Karlstadt/Main at 25./26.6.2004 which had been initiated by Dr Franz-G. Dunkel (Karlstadt). After discussions during the conference the position paper was elaborated by Dr Thomas van Elsen and the authors mentioned above.
Arable plant species as ecological goods – development of a simple method to identify arable fields that are rich in arable plant species
Summary
The complete article is written in German
Plant species diversity has frequently been discussed as an indicator for ecologically sound management methods. Whereas efficient tools for monitoring species diversity already exist in grassland (especially meadows) on which even monetary rewarding systems are based (e.g. Switzerland and Baden-Württemberg, Germany), there is an obvious lack of feasible monitoring and rewarding tools for species diversity in arable land. In the scope of a research project on “simple” indicators for assessing biotic resources on the farm level, a simple method has been developed to assess arable plant species diversity in arable fields. The focus was laid on the feasibility of the method, i.e. the farmers themselves should be able to use the tool. The development of the method and its application are presented. The classification of being rich in plant species is based upon the presence of so called target arable plant species. The chosen method is a “transect-inspection” which consists of three 25 m-sections in the middle of the field. In each 25 m-sample at least 4 target species have to be recorded to characterize the total field as “rich in plant species”. The core set of target species consists of 20 arable plant species that are easily recognized. In 2001 and 2002 „experts“ as well as farmers have tested the method on 42 farms throughout Germany. In 2003 another 39 grain fields have been investigated by using different methods in order to select the best method to deliver accurate and controllable results on species diversity. It is suggested to adjust the core set of target species to different regions and to train the farmers in using the method. The tool that is to be used by the farmers themselves is also regarded as a valuable instrument to promote farmers’ sensibility on the biodiversity in arable fields.
Arable field species on organically and conventionally worked farmland at the Eastern base of the Meißner – Developments throughout the last 30 years
Summary
The complete article is written in German
The Eastern base of the Meißner in North Hessia is known as a particularly species-rich refuge of rare arable field plants. In 2002 new data about the present weed vegetation were gathered in 348 records of vegetation on arable land which was already floristically well examined in the years 1975 and 1990. Differentiated between marginal and inner field areas the phytosociological formation of plant communities and their development is presented. Rare plant communities being typical for limestone soils still exist in that region but they increasingly become impoverished and restricted to field margins. Due to a lack of variety more than 2/3 of the recorded plant species in the inner field areas can no longer be assigned to a vegetation unit. Organic fields show a two to three times higher amount of weed species than conventional ones. Likewise the number of weed species in summer crops is considerably higher than in winter crops. All in all a strong decline of species is detected, especially of rare species which characterize plant societies. Possibilities to improve the protection of species getting rare are discussed.
Changes in the distribution of certain arable weed species in West Hungary – different responses to the modification of agricultural management methods
Summary
The complete article is written in German
By the end of the 20th century West Hungary became a well-developed and intensively managed area, where extensive arable fields survived only in territories of unfavourable site conditions. The changes of the agricultural management methods had different effects on the stands of arable weed species. The changes of the distribution and habitat preference of 7 sample species are discussed as a result of the site and habitat conditions and the agricultural management methods between 1880 and 2005. Due to the intensification Vaccaria hispanica existing only on arable fields disappeared totally. Although Ajuga chamaepitys, Aphanes arvensis, Camelina microcarpa and Valerianella rimosa, which can also be found in fallows and in dry secondary habitats, became rare at different degree, but they still have constant stands in areas having optimal site conditions, moreover Ajuga chamaepitys and Camelina microcarpa exist in naturally dry grasslands as well. The distribution of Montia fontana ssp. chondrosperma is interesting as this species seems to have become more frequent on intensively ploughed fields.
Investigation of weed vegetation on wet segetal fields in South-Western Hungary
Summary
The complete article is written in German
Inland water on soils with bad water balance can lead to serious yield losses. Soil management and plant protection is nearly impossible in these marshy vernal pools, wherefore very special vegetation develops. On the basis of 58 phytocoenological surveys made in South-Western Hungary the vegetation of the vernal pools will be characterised. From phytosociological point of view our surveys stand to Ranunculo sardoi-Alopecuretum geniculati and Myosuro-Ranunculetum sardoi associations the nearest, where the proportion of Nanocyperion elements is significant. The following endangered species occure in these vernal pools: Elatine alsinastrum, Limosella aquatica, Lindernia procumbens, Montia fontana, Peplis portula.
However vernal pools in segetal fields are causing losses from economical aspects, they can contribute to increase agrobiodiversity and have an important role in maintaining numerous threatened and protected plant species (Red Data List, IUCN, Corine Biotopes Project, Bern Convention).
Weed species richness and species composition of different arable field types – A comparative analysis along a climate gradient from south to north Europe
Summary
Comparative investigations on the diversity, frequency and composition of weed floras were performed between 1999 and 2003, within eight separate regions along a climate transect from south Italy up to Finland. The main objective of the investigations was to show up the differences and commonalities between the European regions based on reliable data. Three different field types were analysed: i.) cereals under conventional/integrated farming, ii.) cereals under extensive use/ ecological farming and iii.) fallow fields/set aside fields. Differences between regions and field types were mainly related to the fraction of species with rare or scattered occurrence at the single fields and species with occurrence limited to single regions. In total, 768 species were found on arable fields, with most of them on fallow fields and on unsprayed extensive fields. Only 10 % of all species were found in six or more regions. Cumulative weed frequency was in general higher on fallows and extensive fields. In terms of the predominant species, the differences in the composition of weed floras between the field types were slight.
The occurrence and habitat conditions of Anthoxanthum puelii Lecoq & Lamotte and other Atlantic-Mediterranean weed species in Hungary
Summary
During 2004 and 2005 large stands of Anthoxanthum puelii were discovered in south-western Hungary in “Belso-Somogy” region. These habitats are characterized by the coincidence of climatic and edaphic conditions favourable for this species. Soils in this territory are mainly acidic sandy and the climate is distinctive Subatlantic-Submediterranean. It is uncertain, whether A. puelii is a long established species or whether its invasion in Hungary has just started, because details about its introduction to Hungary are unknown. Hungarian distribution and habitat conditions of other Atlantic-Mediterranean weed species, such as Aphanes microcarpa, Spergula pentandra, Thlaspi alliaceum and Teesdalia nudicaulis are also discussed. These are retreating and endangered plants. According to earlier references Arnoseris minima and Chrysanthemum segetum also occurred in Hungary, but they seem to have disappeared from our flora for two centuries.
Vegetational analyses on organic fields in Middle and Northern Germany
Summary
The complete article is written in German
During the project “Optimising nature conservation on organic farms” farms which implement approaches of nature conservation into practice were investigated. In the context of this project the vegetation of weeds on five organic farms were examined. The field margins and interior areas of the fields were analysed to study the effect of field size on biodiversity. Seven endangered arable field species of the Red List Data Book were detected. In the margins of the fields more endangered species and more complete plant communities than in the interior of the field were found. The results point out the positive contribution of organic farming to the preservation of arable field plants in fields.
The influence of field border plant societies on the weedage of agrophytocoenoses by Arctium tomentosum Mill. (Woolly burdock)
Summary
The complete article is written in German
During 2003-2005 the influence of neighbouring plant societies on the occurrence of Arctium tomentosum Mill. in crop stands was investigated. There were 38 locations situated in four regions in the Czech Republic where the weed species was observed. It could be shown that the weedage of A. tomentosum in crop stands is determined by its occurrence in plant societies adjacent to the field margin. The occurrence of A. tomentosum was recorded in stands of winter wheat, winter barley, triticale, spring barley, sugar beet, maize, winter oilseed rape, mustard, sunflower, pea, poppy, caraway and alfalfa. The plants of A. tomentosum in crop stands were located on average up to 5 m from the field margin in numbers of 0.1-1.6 plants/m2. A. tomentosum occurred at a maximum distance of 4 m from the border of the field in cereals, 9 m in caraway and 15 m in alfalfa. The number of A. tomentosum plants ranged between 0.05-1.3 plants/m2 in alfalfa stands.
Weed succession during three years of set-aside experiment
Summary
Small-plot field trial was carried out in Middle Bohemia in 2002-2004 to describe the changes in weed flora on a set-aside field. Experimental plots were established in common field crop rotation after wheat and sown with: i. grass (Dactylis polygama), ii. grass-legume mixture (Dactylis polygama + Trifolium repens), and iii. leaved as spontaneous fallow. All plots were mulched twice per year. Frequency of plant species and dry biomass production were observed. The highest number (15 species) of – annual plant species was found at the spontaneous fallow in 2002. The highest number of – generative perennial species was found at spontaneous fallow (9 species) in 2003, but the increasing trend of this species was the same at all treatments. The highest number of vegetative perennial species was found also at spontaneous fallow (3 species) in 2003. The highest total biomass was found at the spontaneous fallow in the first year (7.63 t ha-1), but 4.42 t ha-1 of this amount was volunteer wheat. The highest biomass of weeds without volunteers was found in this treatment in second experimental year. On the plot with Dactylis polygama the highest biomass production was also in the second year (2.94 t ha-1). In the grass-legume mixture, the highest biomass of weeds (3.69 t ha-1) was found in the third year.
Bulbous geophytes and their phytosociological state in the South-Hungarian vineyards
Summary
The complete article is written in German
Bulbous geophytes in great numbers can be found on extensive managed fields in South-Hungarian vineyards. This paper deals with the range of bulbous geophytes in this region and based on 37 relevés their phytosociological state will be declared. According to it an impoverished form of Geranio-Allietum, a new weed association in Hungary is described. Important character species of this association are: Allium vineale, Gagea arvensis, Muscari racemosum, Ornithogalum boucheanum, Ornithogalum umbellatum.
The number of bulbous geophytes is constantly decreasing because of intensive growing technologies. Abandonment and modernizing of extensive vineyards make the future of bulbous geophytes question-able. The only hope for preserving them here are effective agricultural environment protection programs.
Status Quo of Weed Management in Organic Farming in the New EU Member States and the Acceding Countries
Summary
Under the EU Specific Support Action (SSA) Project CHANNEL (“Opening Channels of Communication between the Associated Candidate Countries and the EU in Ecological Farming”) a survey about plant protection, organic seed and propagation material, animal husbandry, agricultural technology, weed management and soil fertility is being conducted in 15 Member and Acceding States. The data collection has been aimed at i.) legal and administrative framework, ii.) status quo in practice and iii.) scientific basis.
First results of the weed management questioning of the target group “Experts engaged in practical farming” are presented as a comparison between countries. The analysis shows that a small group of weeds can be identified as main target species for weed management. Alien species are reported from almost all countries and can be identified as a upcoming problem in organic farming. There is conformity among the different countries as regards the choice of prevention tools, whereas there is an obvious lack of modern equipment available to practice mechanical weed control.
Integrated crop management of sugar cane ( Saccharum spp.) and their effects on ecosystem compartments – experience on the Soconusco, Chiapas, Mexico
Summary
The complete article is written in German
Sugarcane is grown on 12.000 ha and hence represents one of the most economically important crops in the Soconusco, Chiapas. Since more than 30 years sugarcane has been cropped with double burning every year (before and after harvest), combined with intensive use of herbicides and of mechanical weeding to guarantee weed free sugarcane fields. These practices selected persistent weed species (Cynodon dactylon) and reduced soil fertility and stability of the agro ecosystem. Since 1998 the effects of integrated cropping management have been analyzed in a long-term experiment. This trial is carried out in Huixtla, Chiapas, and consists of an experimental design with strip system (3 x 100 x 32,5 m) including three cropping management systems (no burning as opposed to one and two burnings), and is laid out in a block design with four repetitions. During eight years, the different cropping management and the growth parameters of sugarcane (stalk height, diameter and number of stalks, juice purity, sugar yield and cost-benefit ratio) were monitored monthly as well as the dynamics of abundance, dominance and diversity of weed communities. Results point towards overwhelming advantage of cutting sugarcane green not only for achieving better growth, higher juice purity and sugar yield but also as a strategy for sustaining long-term reduction of weed aggressiveness off-set by a greater sugarcane biomass production (i.e. stalk height, diameter and number of stalks). Furthermore, differences were noted as to pH as well as to soil organic matter, nitrogen, potassium and phosphorus content. Also were increased earthworm abundance and diversity of formicidae. Double burning of sugarcane resulted in greater weed abundance and dominance. Cropping cane without burning showed a much higher income (2684 €/ha) in comparison with one burning (1964 €/ha) and two burnings (1366 €/ha).
Role of mulching in weed control of organic tomato
Summary
During our examinations we compared weed control effect and yield increasing effect of 8 different types of mulch in tomato. Untreated, hoed and herbicide treated plots were used as control. Years of the experiment were 2000-2005, years with different weather conditions.
In tomato according to summarised results of the years 2000-2005 black plastic covering, paper, and grass clippings were good in suppressing weeds. Examining yield in 2000 plots with black plastic and paper coverings and in 2001 the ones with black plastic and grass clippings gave higher yield than uncovered herbicide treated control treatment. In the extreme year 2002 there was no significant (SD5%) difference among the treatments for the yield. 2003 was a quite arid year and tomato gave uniformly low yield in every plot. In 2004 yields from plots covered with black plastic foil, paper, straw and legume clippings were significantly higher than in herbicide treated plots. In 2005 necessity of mulching was proven because yields of the covered treatments were significantly higher than the one of the herbicide treated control treatment.
Effect of rotational fallows on weed flora of subsequent winter rye
Summary
Rotational fallows could promote farmland biodiversity but might exacerbate weed problems in subsequent crops. A four-year (2003-2006) field experiment was established in southern Finland to study the effects of different types of rotational fallow on the diversity of weed flora and on crop production. Winter rye was sown in autumn 2004 as a subsequent crop after 1-2 year fallows and the reference plots were spring barley and barley stubble. In 2005, weed communities of winter rye were studied by monitoring herbicide-treated (metsulfuron-methyl) and untreated plots. Increased infestation of grass weeds in rye was a clear consequence of fallowing. The most abundant broad-leaved weeds, except Polygonum aviculare, were effectively controlled with metsulfuron-methyl. Various options for weed management should be considered to avoid apparent conflicts between increased risks of weeds and favourable impacts of fallows on biodiversity.
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