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The research was carried out in order to study the molecular mechanisms of herbicide binding (pinoxaden, quizalofop-P-tefuril, prometrin, metribuzin, metsulfuron-methyl) with target proteins (acetyl-CoA-carboxylase, acetolactate synthase, cytochrome P450, 4-hydroxyphenylpyruvate dioxygenase) of weeds growing in Siberia: common wild oat (Avena fatua L.), couch grass (Elymus repens (L.) Gould), red-root amaranthus (Amaranthus retroflexus L.), white gauze (Chenopodium album L.), and green foxtail (Setaria viridis (L) P Beauv). The study was carried out in Novosibirsk oblast in 2022–2023. Using the bioinformatic methods, virtual three-dimensional complexes of pesticides and their targets have been created. A new approach to identifying the parameters of the cavity of binding sites is proposed, which consists in combining the alignment method and the machine-learning technology. Docking of pesticides with targets has been carried out. Calculation of the binding energy indicates a high degree of stability of the ligand-protein complexes. The proposed in silico approach may be useful for elucidating the behavior of herbicides when bound to weed enzymes. This approach allows a deeper understanding of the mechanism of action and ecotoxicological aspects of pesticide use. The complexes of herbicides and proteins involved have a potential high stability due to the low energy of binding to receptors, which varies from –5.60 to –13.24 kcal/mol. The value of the binding energy has not shown a direct dependence on the number of amino acid residues of the ligand-binding site. In general, the study has complemented some aspects of the molecular mechanisms of herbicide binding to weed target proteins; however, more in-depth study is required in order to localize critical amino acid points involved in the biological functions of target proteins. [ABSTRACT FROM AUTHOR]

Couch grass (Elymus repens) is a creeping perennial weed that can cause great yield losses in a wide range of crops. Established stands are usually controlled by glyphosate, selective herbicides, or intensive tillage. Many herbicides, including glyphosate, are, however, currently at risk of being banned. Couch grass can be controlled with below-ground tillage treatments to a depth of 10-15 cm, followed with mouldboard ploughing at a depth of 20-25 cm. Mowing is sometimes used, but often with unsatisfactory results. We wanted to test if there was a better effect of combining a bio-herbicide with autumn mowing and if increased crop competition could further enhance efficacy. One field experiment was carried out in Norway with combinations of bio-herbicide, mowing and competition (cross-sowing of spring cereals) in 2019-2021 and one in Finland with mowing and bio-herbicide in 2019-2020. Pelargonic acid (Beloukha, 680 g a.i. L-1, dose rate 16 L ha-1) was used as bio-herbicide. Couch abundance in autumn, in early and late spring and finally before spring cereal harvest were assessed. In general, each of the treatments caused up to 25-50% short-term reduction in ground cover. The best effect against couch grass was achieved by the combination of all three treatments, with nearly 70% reduction in dry matter in the subsequent summer sampling. However, no treatment combination could reach the same level of efficacy that could be expected with glyphosate.

Background: The main aim of the research was to study short-term changes in the concentrations of elements in two widely distributed plant species, couch grass and nettle and in the rhizosphere soil of the plants. Methods: The sampling of plants and soil was carried out on three dates: 3, 10, and 25 May 2021. On each day of sampling, the plants and soil were collected three times: at 9:00, 14:00, and 19:00. The ICP-OES and ICP-MS analytical techniques were used for determination of elements in the plant and soil samples. The Raman spectroscopy was applied to study variations in the organic compounds. Results: The concentrations of both macro-nutrients and trace elements in plants varied greatly over daytime on all dates of sampling. The differences between concentrations of many elements in the plants collected at different times during a day were statistically significant. There were also statistically significant differences between concentrations of some elements (Na, Mg, P, K, Fe, Ba) in the plants collected on different dates. The relative intensity of diffuse luminescence of the rhizosphere soil of couch grass and nettle was different during daytime and also differed between the soils taken from roots of the two plant species, especially in the beginning of May. Conclusions: The experimental data indicates that the daily variations of the element concentrations in plants might be a result of multiple effects of various factors. The differences in the daily element variations in the couch grass and nettle growing in the same site and collected simultaneously might be due to the fact that these plants belong to different clades. The diurnal fluctuations (that also include regular changes in the element concentrations in plants) can be different for monocotyledons (couch grass) and dicotyledons (nettle). New experimental findings on short-term variations in the concentrations of macro-nutrients and trace elements can help to gain a new insight into accumulation of the elements in different plant species and also be useful in agricultural practice.

There is no information yet about plant species capable of accumulating many different metals/metalloids. The plants feasible for phytoremediation aims must grow fast, have high biomass, deep roots, and should accumulate and tolerate a range of toxicants in their aerial parts. In our research, greenhouse and field experiments have been performed to investigate accumulation and tolerance of not well-studied trace elements such as Br, Eu, Sc, Th (and also U) in couch grass and wheat. We compared bioaccumulation abilities of the plants with those of some other plant species grown under the same conditions. Additionally, we tested the effects of inoculation of seeds with Cellulomonas bacteria on phytoextraction of the trace elements from contaminated soils. For determination of elements, we used neutron activation analysis and ICP-MS. It was found that couch grass and wheat can grow in heavily contaminated soils and accumulate different toxic trace elements to levels that exceed physiological requirements typical for most plant species. Infection of seeds with bacteria resulted in a significant increase in the uptake of various trace elements and their translocation to upper plant parts. The use of couch grass and/or wheat, either alone or in combination with microorganisms, is a promising way to phytoextract metals/metalloids from contaminated soils. [ABSTRACT FROM AUTHOR]

Hybridization, polyploidization, and crop‐to‐wild gene transfer within the agriculturally important tribe Triticeae are well explored experimentally, but the true consequences of both phenomena under natural conditions remain understudied. The present paper reports on an investigation of three species of couch grasses (Elymus hispidus, E. repens, and E. caninus) examining the ploidy levels and absolute genome sizes (1081 plants from 302 natural populations in Central Europe, verified by chromosome counts) and their morphological delimitation. In the present study, the hexaploid level prevailed in E. hispidus and E. repens whereas E. caninus was exclusively tetraploid. Introgressive hybridization between hexaploid species, unidirectionally shifted towards E. hispidus, was indicated by a continual pattern of genome size values. We did not find any evidence for heteroploid hybridization involving tetraploid E. caninus; however, we detected minority cytotypes among both E. caninus plants (hexaploid) and E. repens–E. hispidus hybrids (heptaploid and nonaploid) suggesting the formation of unreduced gametes. Morphometric results (367 plants, redundancy analysis, principal component analysis, and correlation analysis) mirrored the continual homoploid pattern of absolute genome size (including the unidirectional shift), and a significant correlation between absolute genome size and morphology was confirmed. Moreover, morphometric analyses detected additional characteristics for the delimitation of the Elymus taxa under study. Considering the crossability of E. hispidus with Triticum aestivum (bread wheat), the revealed extent of introgressive hybridization has implications for assessing the potential risk of gene flow between crops and troublesome weeds. [ABSTRACT FROM AUTHOR]

Abstract Background The wild relatives of crop species represent a potentially valuable source of novel genetic variation, particularly in the context of improving the crop’s level of tolerance to abiotic stress. The mechanistic basis of these tolerances remains largely unexplored. Here, the focus was to characterize the transcriptomic response of the nodes (meristematic tissue) of couch grass (a relative of barley) to dehydration stress, and to compare it to that of the barley crown formed by both a drought tolerant and a drought sensitive barley cultivar. Results Many of the genes up-regulated in the nodes by the stress were homologs of genes known to be mediated by abscisic acid during the response to drought, or were linked to either development or lipid metabolism. Transporters also featured prominently, as did genes acting on root architecture. The resilience of the couch grass node arise from both their capacity to develop an altered, more effective root architecture, but also from their formation of a lipid barrier on their outer surface and their ability to modify both their lipid metabolism and transporter activity when challenged by dehydration stress. Conclusions Our analysis revealed the nature of dehydration stress response in couch grass. We suggested the tolerance is associated with lipid metabolism, the induction of transporters and the re-programming of development coordinated by ABA. We also proved the applicability of barley microarray for couch grass stress-response analysis.

Baltic salt meadows of the supralittoral are recognizable by a low vegetation structure of perennial plants, distinct zonation, and the presence of characteristic species of high ecological value. This semi-natural, grazing-dependent vegetation is declining in overall distribution and habitat quality. Abiotic and biotic habitat changes as well as the loss of characteristic species and a simultaneous increase of Elytrigia repens are particularly concerning. We hypothesize that, if E. repens increases due to abandonment or other causes, characteristic salt-meadow species will be affected adversely. To investigate the floristic changes and salt meadow species loss over a wide area, we used a dataset of salt meadow plots from along the southern Baltic Sea coast, partitioned by different cover ranges of E. repens. Between these groups, we compared the abundance and frequency of characteristic salt meadow species. We additionally tested (Mann-Whitney-U test) relevant structural factors, plot-based indicator values and strategy types. E. repens indicated low incidence of characteristic salt-meadow species. Soil moisture, salinity and light availability were lower where E. repens occurred; mean vegetation height was increased. Five species co-occurred with Elytrigia repens (Achillea millefolium, Holcus lanatus, Poa pratensis, Schedonorus arundinaceus, Trifolium repens), showing simultaneously a low relative abundance in the remaining dataset. We discuss our findings in terms of frequently observed vegetation changes in the light of salt meadow abandonment. In conclusion, we draw up an easy-to-use method for monitoring salt-meadow medium-term dynamics for applied nature conservation purposes. [ABSTRACT FROM AUTHOR]

The potential growth of buffalo grass (Stenotaphrum secundatum) and couch grass (Cynodon dactylon) on artificial floating islands (AFIs) and their ability to remove total nitrogen (TN) and total phosphorus (TP) from a simulated paper mill wastewater was studied. This was done to assess the potential of AFIs for removal of nutrients from aerated stabilization basins (ASBs) that had occasional growth of blue-green algae (BGA) to bloom levels. Small scale AFIs were prepared using polyethylene foam and planted with the grasses in 30 L of tested water. Trials were conducted in a plastic covered greenhouse over a three-month period where temperatures ranged from 15 to 44 °C. The results showed that both buffalo and couch grasses can adapt to planting in AFIs showing increases of 125% and 148% in wet weight, respectively. Nutrient uptake by buffalo grass and couch grass were found to be similar. Percentage uptakes of TP and TN from the synthetic water by the buffalo grass were 82% and 47%, whereas by couch grass, uptakes were 83% and 45%, respectively. [ABSTRACT FROM AUTHOR]

Background: The wild relatives of crop species represent a potentially valuable source of novel genetic variation, particularly in the context of improving the crop’s level of tolerance to abiotic stress. The mechanistic basis of these tolerances remains largely unexplored. Here, the focus was to characterize the transcriptomic response of the nodes (meristematic tissue) of couch grass (a relative of barley) to dehydration stress, and to compare it to that of the barley crown formed by both a drought tolerant and a drought sensitive barley cultivar. Results: Many of the genes up-regulated in the nodes by the stress were homologs of genes known to be mediated by abscisic acid during the response to drought, or were linked to either development or lipid metabolism. Transporters also featured prominently, as did genes acting on root architecture. The resilience of the couch grass node arise from both their capacity to develop an altered, more effective root architecture, but also from their formation of a lipid barrier on their outer surface and their ability to modify both their lipid metabolism and transporter activity when challenged by dehydration stress. Conclusions: Our analysis revealed the nature of dehydration stress response in couch grass. We suggested the tolerance is associated with lipid metabolism, the induction of transporters and the re-programming of development coordinated by ABA. We also proved the applicability of barley microarray for couch grass stress-response analysis. [ABSTRACT FROM AUTHOR]

Cynodon dactylon (cynodon) is a weed that is particularly difficult to control due to its ability to reproduce readily using stolons and rhizomes. Although glyphosate is the most commonly used herbicide to control cynodon, current recommendations involve repetitive applications, which appear likely to select for resistance. Rotating glyphosate with herbicides that have different modes of action will be a more sustainable strategy for cynodon control. Earlier work suggested that the growth of cynodon is strongly inhibited by imazapyr, an herbicide that inhibits the acetohydroxy acid synthase (AHAS) enzyme. The optimum time for application of imazapyr on cynodon, and the subsequent inhibition of AHAS activity in cynodon are unknown. The aims of this study were firstly, to determine the effectiveness of inhibiting AHAS activity when applied at different times of the year, and secondly to compare the efficacy of foliar and root applications. Results showed that application time has a significant effect on the efficacy of imazapyr to inhibit enzyme activity, with mid–late summer being optimal, and furthermore that the herbicide can be absorbed by both the shoots and the roots. [ABSTRACT FROM AUTHOR]

The objective of this research was to investigate occurrence of common couch grass (Elytrigia repens (L.) Desv. ex Nevski) under different grassland management by means of a small-plot trial. The trial was managed during 2003–2011 with four levels of utilisation: intensive (4 cuts per year, 1st cut on 15 May), medium intensive (3 cuts per year, 1st cut on 30 May), low intensive (2 cuts per year, 1st cut on 15 June), and extensive (2 cuts per year, 1st cut on 30 June). Four rates of fertilisation were applied for each utilisation treatment: nil-fertilisation, P30K60, N90P30K60, and N180P30K60 (pure nutrients). The intensively utilised treatments without N fertilisation showed the lowest mean percentage cover of couch (3.0 %, and 2.8 %, respectively). Further, we found a significant increase in couch grass cover (up to about 30 %) as a response to nitrogen fertilisation and it was most significant in grasslands utilised with two cuts per year. It can be concluded that grassland utilisation in three cuts per year and the dose 90 kg.ha−1 of nitrogen led to the maintenance of the occurrence of couch at the reasonable level up to 10–15 %.

Without herbicides, the control of Elymus repens relies on intensive tillage, often in the form of repeated post-harvest stubble cultivations followed by ploughing. This is costly and time-consuming and also increases the risk of nitrogen leaching. Our aim was to quantify the controlling effect on E. repens of single and repeated cultivation and differing time of cultivation in relation to spring cereal harvest. A 2-year experiment was conducted at two sites in the south and east of Sweden in 2011-2012 and 2012-2013. We compared no, single and repeated tine cultivation followed by mouldboard ploughing; the single cultivation was performed directly after harvest or 20 days after harvest; when repeated, the first cultivation was performed immediately or 5 days after harvest, followed by a second cultivation 20 days after harvest. Tine cultivation in combination with mouldboard ploughing resulted in 50-70% lower rhizome biomass, and increased average subsequent cereal yields by 0-130% compared with ploughing alone. Large E. repens populations appeared to be more efficiently reduced by tine cultivation than smaller populations. A single tine cultivation 20 days after harvest tended to result in a higher E. repens shoot density and more rhizome biomass in the subsequent year than tine cultivation directly after harvest. Additional cultivation 20 days after harvest did not improve control of E. repens or the subsequent cereal grain yield, compared with a single cultivation conducted directly after harvest. In conclusion, preventing the growth of E. repens during the early part of the post-harvest autumn period was more important than starving rhizomes with repeated cultivations. [ABSTRACT FROM AUTHOR]

Two potential control methods for Elymus repens, which do not disturb the soil, are post-harvest mowing and competition from under-sown cover crops. Our aim was to quantify the effect of cover crop competition and mowing on E. repens and to evaluate the potential for combining the two methods. We present a two-factorial split-plot experiment conducted at three locations in Sweden, in two experimental rounds conducted in 2011-2012 and 2012-2013. A spring cereal crop was under-sown with perennial ryegrass, red clover or a mixture of the two (subplots). Under-sown crops were either not mowed, or mowed once or twice post-harvest (main plots). This was followed by ploughing and a new spring cereal crop the next year. Mowing twice reduced autumn shoot biomass by up to 66% for E. repens and 50% for cover crops compared with the control, twice as much as mowing once. Pure ryegrass and mixture treatments reduced E. repens shoot biomass by up to 40% compared with the control. Mowing twice reduced rhizome biomass in the subsequent year by 35% compared with the control, while the pure red clover treatment increased it by 20-30%. Mowing twice and treatments including red clover resulted in higher subsequent grain yields. We concluded that repeated mowing has the potential to control E. repens, but a low-yielding cover crop has insufficient effect on rhizome biomass. Clover-grass mixtures are of interest as cover crops, because they have the potential to increase subsequent crop yield and even at low levels they reduce E. repens above-ground autumn growth. [ABSTRACT FROM AUTHOR]

Field experiments quantified factors affecting root growth and anchorage by transplanted 'Tifgreen' (Cynodon dactylon (L.) Pers. x Cynodon transvaalensis Burtt Davy) sod, a globally important warm-season C4 turfgrass. Vertical force required to detach recently transplanted sod from underlying soil was the measure of root anchoring strength. In early spring, date of sod harvest and transplantation was important to root growth and anchorage measured 30 days after transplantation. Delaying sod harvest/transplantation by about a month after the end of the winter shoot dormancy period increased root anchoring strength 200% and root dry mass 640% during the 30 days after sodding. The strong effect of early-spring sodding date on root anchorage was related to cumulative thermal time before sod harvesting. Root anchoring strength was directly proportional to the number, but not mass, of roots produced by transplanted sod. In late spring, anchoring of sod to very firm traffic-compacted clay was 87% greater than to loamy sand, measured 14 days after sodding. N-P-K fertilisation did not affect late-spring sod anchorage to loamy sand soil, measured 18 days after sodding, but did enhance shoot density and colour. Sod root penetration into a silt loam soil was unaffected by an initially dry surface layer when sufficient irrigation was used. Overall, root anchorage by transplanted Tifgreen sod was similar to, or greater than, values reported for cool-season C3 turfgrasses in similar circumstances. [ABSTRACT FROM AUTHOR]

Mechanical weed control of perennial weeds in organic crop production over long post-harvest periods is incompatible with the establishment of cover crops for improving soil quality and preventing nutrient leaching. We suggest a new concept that comprises uprooting and immediate removal of vegetative propagules located within the plough layer to allow for quick re-establishment of a plant cover. A field experiment comparing the effects of conventional practices (stubble cultivation) with different combinations of rotary cultivation (One, Two or four passes) and cover crops (none vs. rye-vetch-mustard mixture) on Elytrigia repens rhizome removal, shoot growth and suppression of a subsequent barley crop was examined in two growing seasons. Four passes with a modified rotary cultivator, where each pass was followed by rhizome removal, reduced E. repens shoot growth in barley by 84% and 97%. In general, the cover crop developed poorly and did not affect barley or E. repens. Barley yield was only affected by treatments in the first season, where yield was negatively correlated with E. repens shoot biomass. The concept has potential for the control of severe E. repens infestations, but future research aimed at identifying more effective smother crops and less intensive methods of rhizome removal is needed. [ABSTRACT FROM AUTHOR]

Background: The main aim of the research was to study short-term changes in the concentrations of elements in two widely distributed plant species, couch grass and nettle and in the rhizosphere soil of the plants., Methods: The sampling of plants and soil was carried out on three dates: 3, 10, and 25 May 2021. On each day of sampling, the plants and soil were collected three times: at 9:00, 14:00, and 19:00. The ICP-OES and ICP-MS analytical techniques were used for determination of elements in the plant and soil samples. The Raman spectroscopy was applied to study variations in the organic compounds., Results: The concentrations of both macro-nutrients and trace elements in plants varied greatly over daytime on all dates of sampling. The differences between concentrations of many elements in the plants collected at different times during a day were statistically significant. There were also statistically significant differences between concentrations of some elements (Na, Mg, P, K, Fe, Ba) in the plants collected on different dates. The relative intensity of diffuse luminescence of the rhizosphere soil of couch grass and nettle was different during daytime and also differed between the soils taken from roots of the two plant species, especially in the beginning of May., Conclusions: The experimental data indicates that the daily variations of the element concentrations in plants might be a result of multiple effects of various factors. The differences in the daily element variations in the couch grass and nettle growing in the same site and collected simultaneously might be due to the fact that these plants belong to different clades. The diurnal fluctuations (that also include regular changes in the element concentrations in plants) can be different for monocotyledons (couch grass) and dicotyledons (nettle). New experimental findings on short-term variations in the concentrations of macro-nutrients and trace elements can help to gain a new insight into accumulation of the elements in different plant species and also be useful in agricultural practice., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s). Published by IMR Press.)

Bergkvist G, Adler A, Hansson M & Weih M (2010). Red fescue undersown in winter wheat suppresses Elytrigia repens. Weed Research 50, 447–455. Elytrigia repens (syn. Elymus repens) is a perennial grass weed that is controlled by herbicides or by tillage. Both methods are expensive and may have negative effects on the environment. Therefore, alternative methods of weed control, such as using competition from under-sown perennial forage crops, are of interest. Red fescue can be sown together with winter wheat as a non-flowering understorey crop that has its main growth during late summer and autumn. This study quantified the effect of red fescue and E. repens on wheat biomass and tested the hypothesis that under-sown red fescue reduces the amount of E. repens rhizomes and thus the need for herbicides or tillage. Two field experiments in which winter wheat, red fescue and E. repens were grown in all possible combinations were conducted between 2003 and 2005. Elytrigia repens reduced wheat biomass by 8%, while red fescue had no significant effect on wheat biomass. Red fescue reduced late autumn biomass of E. repens rhizomes by 40%. The results suggest that red fescue sown with winter wheat can reduce propagation of E. repens during summer and autumn, without a significant reduction in wheat biomass. [ABSTRACT FROM AUTHOR]

Tørresen KS, Fykse H & Rafoss T (2010). Autumn growth of Elytrigia repens, Cirsium arvense and Sonchus arvensis at high latitudes in an outdoor pot experiment. Weed Research 50, 353–363. Autumn growth of weeds (i) provides an opportunity for mechanical and chemical control in autumn and (ii) can be important for weed survival and infestation in the following spring. Growth characteristics of Elytrigia repens, Cirsium arvense and Sonchus arvensis in autumn were studied in 2004 and 2005, on plants of different origins and developmental stages (planted at various times from May to August). The plants were grown outdoors in large pots and were assessed during September and October each year. The study showed that (i) all species grew in autumn, but growth ceased and the species withered at different times; S. arvensis first, followed by C. arvense and then E. repens and (ii) less developed (i.e. younger) plants grew later in the autumn. This was demonstrated by leaf area development and biomass distribution during autumn. Older plants had a greater total biomass with relatively more rhizomes or creeping roots than younger plants. In young plants of C. arvense and S. arvensis, the biomass of creeping roots increased during autumn. The total biomass, however, changed little during autumn. These growth patterns indicate that E. repens will be the easiest, S. arvensis the most difficult and C. arvense in between, regarding control of these species in autumn. [ABSTRACT FROM AUTHOR]

Brandsæter LO, Fogelfors H, Fykse H, Graglia E, Jensen RK, Melander B, Salonen J & Vanhala P (2010). Seasonal restrictions of bud growth on roots of Cirsium arvense and Sonchus arvensis and rhizomes of Elymus repens. Weed Research 50, 102–109. The success of weed management aimed at depleting the regenerative structures of perennial weeds depends largely on the sprouting activity of rhizome and root buds. Seasonal variation in sprouting of these buds on Cirsium arvense, Sonchus arvensis and Elymus repens was studied for plants collected from Denmark, Finland, Norway and Sweden. At 2-week intervals from July to October, 5-cm fragments of roots or rhizomes were cut from plants grown in buckets and planted into soil in pots, half of which were placed immediately into growth chambers at 18°C for 4 weeks. The other half of the pots were initially placed in a dark room at 2°C for 4 weeks before being transferred to the same growth chamber, also for 4 weeks. During the growth chamber period, the numbers of emerged shoots in each pot were counted weekly. The sprouting activity of C. arvense and E. repens was relatively uniform during this period and bud dormancy was not apparent. In all ecotypes of S. arvensis, innate bud dormancy developed during the latter part of the growing season. For all three species, differences in sprouting readiness were found among ecotypes. The results imply that C. arvense and E. repens are more likely to be controlled by mechanical measures in autumn than S. arvensis. [ABSTRACT FROM AUTHOR]

The effects of irrigation and fertiliser regimes on N leaching from the production of couch grass ( Cynodon dactylon L.) sod, on a free-draining sandy soil, were evaluated in a 22-month field study. The experimental design used a randomised-block, split-plot design with three replicates. Main plots consisted of two irrigation treatments: 70 and 140% daily replacement of pan evaporation; four subplot fertiliser types (water-soluble (predominately NH4NO3), control-release, pelletised poultry manure and pelletised biosolids); and three N application rates (100, 200 and 300 kg N ha−1 per crop). Nitrogen leaching was assessed by measuring the leachate volumes and concentrations of N species leached from soil lysimeters (250 mm in diameter by 950 mm in length) installed in 10 m2 turfgrass plots. Nitrogen leaching ranged from 33 to 167 kg N ha−1 over 22 months, depending upon the irrigation and fertiliser treatment. Irrigation treatment affected N leaching more than fertiliser treatment, and increasing the irrigation from 70 to 140% replacement of daily pan evaporation increased N leaching for all fertiliser types, and by up to four times. Forty six to 76% of losses occurred from the high irrigation treatments during the first 16 weeks after the turfgrass was planted as rhizomes. By contrast, N leaching did not appear to increase following harvest of sod. At the high irrigation treatment, N leaching was greater for the pelletised biosolids than the control-release; while at the low irrigation treatment, N leaching did not vary between fertiliser types. A significant proportion of the N leached was in the organic form. Therefore, we recommend total N and mineral N be measured when assessing N leaching from turfgrass. Nitrogen leaching from turfgrass production is low from all fertiliser types when the irrigation matches turfgrass water use and N is applied at a rate and frequency that approximates turfgrass requirements. [ABSTRACT FROM AUTHOR]

The effects on growth, quality and N uptake by turfgrass ( Cynodon dactylon L.) during sod production of four fertiliser types applied at three application rates (100, 200 or 300 kg N ha−1 per ‘crop’) under two irrigation treatments (70% and 140% daily replacement of pan evaporation) were investigated. The fertiliser types were: water-soluble (predominately NH4NO3), control-release, pelletised poultry manure, and pelletised biosolids; and the experiment was conducted on a sandy soil in a Mediterranean-type climate. Plots were established from rhizomes, with the turfgrass harvested as sod every 16–28 weeks depending upon the time of the year. Four crops were produced during the study. Applying water-soluble and control-release fertilisers doubled shoot growth and improved turfgrass greenness by up to 10% in comparison with plots receiving pelletised poultry manure and pelletised biosolids. Nitrogen uptake into the shoots after four crops (averaged across irrigation treatments and N rates) was 497 kg N ha−1 for the water-soluble fertiliser, 402 kg N ha−1 for the control-release, 188 kg N ha−1 for the pelletised poultry manure and 237 kg N ha−1 for the pelletised biosolids. Consequently, the agronomic nitrogen-use efficiency (NAE, kg DM kg−1 N applied) of the inorganic fertilisers was approximately twice that of the organic fertilisers. Increasing irrigation from 70% to 140% replacement of pan evaporation was detrimental to turfgrass growth and N uptake for the first crop when supplied with the water-soluble fertiliser. Under the low irrigation treatment, inorganic N fertilisers applied at 200–300 kg N ha−1 were adequate for production of turfgrass sod. [ABSTRACT FROM AUTHOR]

The composition of biologically active substances of aqueous extracts of couch grass was studied and the following groups of biologically active substances were identified: coumarins, iridoids, saponins, slimes, polysaccharides (including inulin), ascorbic acid and β-carotene, flavonoids (rutin, hyperoside, baicaleine) phenocarboxylic acids (chlorogenic and p-hydroxycinnamic acids), and tannins. The effects of couch grass extract in the form of a cream on several measures of lipid peroxidation in allergic contact dermatitis were studied in experimental conditions. Cream containing couch grass extract was found to have normalizing actions on measures of lipid peroxidation (diene conjugates, malondialdehyde, catalase) in the plasma of experimental animals. [ABSTRACT FROM AUTHOR]

Approaches to managing invasive plants is challenging, particularly in protected areas where conventional methods, such as chemical herbicide applications are limited. We studied the effects of varying densities of Cynodon dactylon on the growth and development of the invasive weeds Tagetes minuta and Gutenbergia cordifolia in northern Tanzania. We conducted pot and field plot experiments following a completely randomized block design that was replicated three times. Increasing densities of C. dactylon significantly reduced growth, leaf total chlorophyll, biomass and significantly increased leaf anthocyanin of both T. minuta and G. cordifolia invasives. Our results further showed that the critical density of C. dactylon to suppress the two invasive species is ≥ 8 plants/m2. We suggest that C. dactylon can successfully be used as an alternative eco-friendly and sustainable approach for managing invasive weeds, such as T. minuta and G. cordifolia. This management technique can additionally improve forage production and biomass for wild and domestic herbivores in the affected areas. [ABSTRACT FROM AUTHOR]