Myuros Research Articles

Potential use of Schumannianthus dichotomus waste: the phytotoxic activity of the waste and its identified compounds

The phytotoxic potential of the leaves and twigs of Schumannianthus dichotomus, discarded in the mat-making industry against four test plants (lettuce (Lactuca sativa L.), rapeseed (Brassica napus L.), foxtail fescue (Vulpia myuros (L.) C.C. Gmel.) and timothy (Phleum pratense L.)) was investigated and found strong phytotoxic activity. An assay-guided fractionation of S. dichotomus extarcts against cress (Lepidium sativum L.) through a series of column chromatography steps yielded two compounds, 8-(5-oxo-2,5-dihydrofuran-2-yl) octanoic acid (ODFO) and (E)-6-hydroxy-2,6-dimethylocta-2,7-dienoic acid (8-carboxylinalool). ODFO and 8-carboxylinalool showed strong phytotoxic activity against cress and timothy. The concentrations required for 50% growth inhibition (I50 value) of the seedlings of cress and timothy were 111.94–128.01 and 36.30–91.75 µM, respectively, for ODFO, but the values were much higher at 315.98–379.13 and 107.92–148.41 µM, respectively, for 8-carboxylinalool, indicating the stronger phytotoxic activity of ODFO. This study is the first to isolate ODFO and 8-carboxylinalool from S. dichotomus and their phytotoxic potential while ODFO is firstly encountered from any natural source. The growth inhibitory activity of the identified compounds may explain their role in the phytotoxic activity of S. dichotomus, which suggests the possible use of its leaves and twigs or its active constituents as natural bioherbicides.

Comparison of Tea Tree (Camellia sinensis L.) Growth and Weed Occurrences by a Green Manure Crop

본 연구는 친환경 차나무 재배에서 월동 풋거름작물 재배시 차나무의 생육특성 및 잡초발생에 미치는 영향을 알아보고, 차나무 관리에 유용한 초종을 선발하기 위한 기초적 자료를 얻기 위하여 수행하였다. 무처리의경우 13종의 잡초 229주, 생체중 4,344 g (건물중 745 g)이 조사되었으며, 크림슨클로버 처리에서 가장 적은 3.7 종의 잡초 14.7주, 생체중 18.0 g (건물중 1.1 g) 조사되었으며, 모든 풋거름작물 처리구에서 98% 이상 잡초방제효과가 있었다. 토양유기물 함량은 무처리 14.1 g/kg으로 가장 낮았으며, 크림슨클로버 처리에서 가장 많은 2.2 배 증가한 30.5 g/kg 함량을 보였다. 차나무 생엽의 엽록소함량은 무처리 38.1, 들묵새 처리 38.3, 자운영 처리40.1, 크림슨클로버 처리 41.9로 조사되었으며, 엽록소형광에서도 크림슨클로버 처리 0.804 Fv/Fm로 가장 높았다. 잡초억제, 토양개선효과, 차나무 생육 등을 고려하였을 때, 차나무의 풋거름작물로 크림슨클로버가 가장 적합한 것으로 사료된다.This study examined the effects of green manure on the growth characteristics and weed control for tea trees in organic tea cultivation. The weed control, soil chemistry, SPAD value, and chlorophyll fluorescence were examined with five different treatments [Festuca myuros (FES), Astragalus sinicus (AST), Trifolium incarnatum (TRI), mixing sowing (Astragalus sinicus 1 + Trifolium incarnatum 2) and control]. The weed occurrence was 229 weeds of 13 flora (fresh weight 4,344 g, dry weight 745 g) in control; TRI treatment was the lowest, 14.7 weeds of 3.7 flora (fresh weight 18.0 g, dry weight 1.1 g). The mulching treatment groups showed a weed inhibition effect compared to the control (over 98%). Organic matter was lowest at 14.1 g/kg, but highest at 30.5 g/kg (2.2 times) in the TRI treatment. SPAD value and chlorophyll fluorescence of tea leaves were also highest in the TRI treatment (38.1, 41.9 Fv/Fm). Therefore, Trifolium incarnatum is considered the most effective when considering weed control, soil chemical properties, growth of tea trees, and convenience of work.

Biology and Management of Vulpia myuros-An Emerging Weed Problem in No-Till Cropping Systems in Europe.

Recently, Vulpia myuros has become a problematic grass weed species in parts of Europe. It is most common in no-till cropping systems. The inherent tolerance to several selective grass weed herbicides is of serious concern to the successful management of V. myuros in arable farming. Here, we reviewed the available knowledge about the biology of V. myuros to identify knowledge gaps and assess management efforts to identify best practices for control. V. myuros is a winter-annual species producing seeds with a short dormancy that can germinate at a wide range of conditions. Seed longevity in the soil is short. Little information is available on the influence of V. myuros on crop yield but some results suggest that yield losses can be significant. The findings provide a better understanding of the weedy characteristics of V. myuros and highlight that management strategies in Europe need to be diversified and integrate preventive and cultural control methods. Finally, we identify some of the management tools that should be considered to minimize the impact of V. myuros on European farming and future needs for research to develop sustainable integrated weed management strategies.

Post-Fire Management-Scale Trials of Bacterial Soil Amendment MB906 Show Inconsistent Control of Invasive Annual Grasses

Rangeland managers need tools to control invasive annual grasses, particularly following wildfire. We assessed responses of native and invasive/exotic grasses to the MB906 soil amendment containing live cultures of a purportedly weed-suppressive strain of the bacterium Pseudomonas fluorescens (“WSB”). MB906 was applied alone and in combination with the pre-emergent herbicide imazapic on >3000 ha across three sagebrush-steppe landscapes burned several months prior. Replicate plots of each treatment type were established and plant cover was measured in the following three years. Cover of invasive-annual grasses (“IAG”) was not responsive to MB906 when all IAG species were considered (“IAG-All”). However, MB906 led to a 54% reduction in the IAG's that were previously reported to be controlled by WSB (“IAG-Target”) in the second year following application (IAG-Target = cheatgrass, Bromus tectorum and medusahead, Taeniatherum caput-medusae; IAG-All also includes Vulpia myuros and Bromus arvensis). MB906 reduced the effectiveness of co-applied imazapic: Imazapic alone reduced IAG-All by 83% and 68% in years 1 and 2, respectively, while imazapic+MB906 reduced IAG-All by 48% and 38% in years 1 and 2, respectively, across all landscapes, and a similar response pattern was observed for IAG-Target. Perennial grass cover was unaffected by the treatments except where it increased 4-fold in response to imazapic applied at a high rate (0.140 kg a.i. ha−1) in one of the landscapes. Tank mixing MB906 and herbicide may have lessened the biological activity of the herbicide by altering the pH or mineral content of the spray solution or by direct metabolism of the herbicide by the bacteria. These results do not provide strong support for MB906 as a tool for annual grass control, though they suggest further investigation may be warranted.

Repeated, high-severity wildfire catalyzes invasion of non-native plant species in forests of the Klamath Mountains, northern California, USA

Non-native plant invasions are often catalyzed by wildfires and may alter the structure, function, and composition of ecosystems. Of particular concern are non-native annual grasses that promote increased fire frequency and compete with native vegetation for early season moisture. While these effects are well studied in non-forested ecosystems, relatively few studies document invasions of non-native annual grasses in forested ecosystems. We document non-native plant invasion following repeated high-severity wildfire in mixed-conifer/hardwood forests dominated by Douglas-fir (Pseudotsuga menziesii) in the Klamath Mountains of northern California. Despite great concern regarding the loss of conifer dominance and transitions to non-forested states related to recent and projected increases in wildfire activity, there is little known about invasions of non-native plant species following fire in this region. Non-native plant species capable of long-distance dispersal had an average total cover of 26% and were ubiquitous across a systematic, gridded sample of twenty 800 m2 plots. Non-native forbs included multiple species of common post-disturbance invaders (e.g. Cirsium vulgare, Senecio sylvaticus, Lactuca serriola). Non-native annual grasses comprised more of the vegetative cover than non-native forbs (17% vs. 9%), and were dominated by two species, Aira caryophyllea and Vulpia myuros, which reached as high as 80% cover. Our findings indicate that non-native annual grasses are a novel stressor that may accelerate projected loss of conifer dominance in the Klamath Mountains by facilitating fire spread and increasing competition for early season soil moisture. Additional monitoring will be crucial to understanding the impacts of non-native plants as fire activity in this region continues to increase.

Nitrogen fertilization for hay and seed from endophyte‐free and endophyte‐infected tall fescue

AbstractTall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] is an important forage, but a fungal endophyte often found in the aboveground biomass can negatively affect animal production. Nitrogen also affects production, but data are limited regarding N fertilization effects on hay and seed yields from endophyte‐free (EF) compared with endophyte‐infected (EI) tall fescue grown on claypan soil in the eastern Great Plains. This study's objective was to determine the effects of N fertilizer timing and rate on EF and EI tall fescue yield of R4 (anthesis) hay, seed, and hay residual after seed harvest (stubble hay, SH). Endophyte infection did not affect R4 hay, seed, or SH yields and did not interact with N timing, N rate, or year for any measured parameters. Across the 3‐yr study, N fertilizer applied in late fall resulted in 18% greater seed production than late winter, with split late fall/late winter applications being intermediate. The effect of N timing on R4 and SH varied by year. Annual fescue seed yield response to N rate varied, but required 112 kg N ha−1 or more to achieve near 300 kg ha−1 in better‐yielding years. Hay measured at R4 or SH responded to N up to at least 168 kg ha−1. Hay N concentration was diluted with initial increments of N fertilizer but increased as yield response diminished with greater N rates. Simple return functions suggest that the N rate to achieve maximum economic return is reduced when N fertilizer costs are high and when seed/hay selling prices are low.

Effects of different grasses cultivation on apple orchard soil microbial community

Taking naturally growing grass (NG) as comparison, high-throughput sequencing technique was adopted to examine the effects of Lolium perenne (LP), Trifolium repens (TR), Vulpia myuros (VM), and Vicia villosa (VV) cultivation on soil microbial community in apple orchard of Yanggu County, Shandong Province, and the correlations of soil microbial community with soil nutrient and physicochemical property. The results showed that LP increased the relative abundance of Alternaria and Aspergillus in soil, TR increased that of Gibberella, VM increased Aureobasidium and Chaetomium, and VV increased probiotics such as Nitrososophaera and Metarhizium. However, the quantity of pathogenic bacteria Ralstonia was improved in NG treatment. Results from Spearman correlation analysis showed that the abundance of Bacillus was significantly positively correlated with the concentration of soil organic matter. The abundance of Aspergillus was significantly negatively correlated with available phosphorus, available potassium, CEC, and organic matter. The abundance of Metarhizium was significantly positively correlated with soil pH and CEC. Planting VV between rows of apple orchards, and enhancing the soil organic matter and nutrients content in a certain extent, helped to improve soil micro-ecological environment.

Garcienone, a Novel Compound Involved in Allelopathic Activity of Garcinia Xanthochymus Hook.

Plants are sources of diversified allelopathic substances that can be investigated for use in eco-friendly and efficient herbicides. An aqueous methanol extract from the leaves of Garcinia xanthochymus exhibited strong inhibitory activity against barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), foxtail fescue (Vulpia myuros (L.) C.C.), alfalfa (Medicago sativa L.), and cress (Lepidium sativum L.), and appears to be a promising source of allelopathic substances. Hence, bio-activity guided purification of the extract through a series of column chromatography steps yielded a novel compound assigned as garcienone ((R, E)-5-hydroxy-5-((6S, 9S)-6-methyl-9-(prop-13-en-10-yl) tetrahydrofuran-6-yl) pent-3-en-2-one). Garcienone significantly inhibited the growth of cress at a concentration of 10 μM. The concentrations resulting in 50% growth inhibition (I50) of cress roots and shoots were 120.5 and 156.3 μM, respectively. This report is the first to isolate and identify garcienone and to determine its allelopathic potential.

Effects of various ecological factors on the germination of two crop and pasture weed species, Vulpia bromoides and Vulpia myuros

Vulpia species (silver grasses), including V. bromoides and V. myuros, are native to the Mediterranean, Middle East and Eurasia, but have become dispersed worldwide. These two species reduce the grazing quality of pastures, frequently co-occur and are often associated with poor-quality acidic soils. This study investigated two species, Vulpia bromoides and V. myuros. Germination trials tested the effects of seasonal temperature, light,pH, moisture, salinity, pre-germination heat shock and smoke, and seed burial depth. Vulpia bromoides germinated well regardless of temperature or light (>80%, all conditions), whereas V. myuros preferred lower temperatures and absence of light (97%, 7/17oC in 24-h dark). Under different culture conditions, the two species germinated well across the pH range 4 to 10 (>85%). Reduced moisture, pre-germination heat shock and smoke, and increased burial depth reduced germination and emergence of both species. Preventing germination of these species in pastures must begin before or during winter. Fire may be useful for control, butsufficiently high temperatures must be achieved to kill seeds. Tillage to bury seeds, prior to pasture renovation, may prevent germination of seeds.

Study of the allelopathic activity of Garcinia pedunculata Roxb

The allelopathic properties of plants can be used as an alternative weed control method to reduce the use of synthetic herbicides. Accordingly, the present study was carried out to determine the allelopathic activity of Garcinia pedunculata. Six different concentrations of aqueous methanol extracts of G. pedunculata fruit were prepared and used to determine their effect on the growth of eight test plants: alfalfa (Medicago sativa L.), cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), rapeseed (Brassica napus L.), barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), foxtail fescue (Vulpia myuros (L.) C.C. Gmel.), Italian ryegrass (Lolium multiflorum Lam.), and timothy (Phleum pratense L.). The test plants were grown in Petri dishes and after 48 h incubation, the length of the roots and shoots of the seedlings was measured and compared with control seedlings. Experiments were carried out in a completely randomized design (CRD). Analysis of variance (ANOVA) of the data was performed using the SPSS statistical package, and the I50 values were measured from a regression equation. The extracts at each concentration significantly inhibited the shoot and root growth of all the test plants, except the concentration of 0.001 g dry weight equivalent extract/mL, compared with control. At a concentration of 0.3 g of dry weight equivalent extract/mL, the shoot and root growth of all the tested plants were completely inhibited, except the shoot growth of barnyard grass. The degree of inhibition increased in line with increased extract concentration. The shoots of alfalfa and the roots of barnyard grass were determined to be the most susceptible to the G. pedunculata extract based on the concentration of extract resulting in 50% (I50) growth inhibition of the test plants. These results suggest that G. pedunculata may have allelopathic potential and may possess allelochemicals. From our study, we can conclude that G. pedunculata could be developed as an eco-friendly weed control option.

Potential Risks of Poaceous Plants as Infectious Sources of Rice Black-Streaked Dwarf Virus Transmitted by the Small Brown Planthopper, Laodelphax striatellus.

The recent reemergence of rice black-streaked dwarf virus (RBSDV) has caused severe rice yield losses in several areas of East Asia. To identify the most important infectious sources of RBSDV, we compared the susceptibility of major poaceous plants to RBSDV infection and survival and the RBSDV acquisition efficiency of a vector insect, the small brown planthopper Laodelphax striatellus. RBSDV infection and survival rates of L. striatellus were significantly high in wheat (Triticum aestivum 'Norin61') and rice (Oryza sativa 'Reiho'), indicating that these crops can be important sources of RBSDV. Our results also showed that RBSDV can complete its infection cycle between Italian ryegrass (Lolium multiflorum 'Hataaoba') and L. striatellus. These results indicate that control of RBSDV and L. striatellus on winter-spring crops of wheat and Italian ryegrass may avoid an RBSDV epidemic on rice during the following summer. In addition to infections of wheat and Italian ryegrass, RBSDV infections were detected in Avena fatua, Avena sterilis subsp. ludoviciana, Cynosurus echinatus, Festuca arundinacea, Festuca pratensis, Lolium perenne, and Vulpia myuros var. megalura, although the infection efficiency varied.

Evaluation of allelopathic competency of Lamium amplexicaule and identification of its allelopathic active substance

The weedy annual grass Lamium amplexicaule (L.) originated from the Mediterranean region, spreads quickly, and becomes naturalized in areas it invades. It was assumed that volatile phytotoxic substances are one of the invasive characteristics of L. amplexicaule. However, no volatile compound has been found. Therefore, we re-evaluated the allelopathic potential of L. amplexicaule and investigated the phytotoxic substances with allelopathic activity. An extract of L. amplexicaule inhibited the root and shoot growth of Lepidium sativum, Lactuca sativa, Arctium lappa, Lolium multiflorum Lam., Echinochloa crus-galli, and Vulpia myuros, which indicates that the extract has an allelopathic effect. The extract was purified using bioassay-guided chromatographic separations, and a phytotoxic substance with allelopathic activity was isolated and characterized as methyl caffeate. The compound significantly inhibited the root and shoot growth of L. sativum and L. multiflorum. The present results suggest that methyl caffeate may contribute to the allelopathic effect of the L. amplexicaule extracts and consequently, may be partly responsible for the invasive characteristics of the species.

Assessment of allelopathic potential of Coccinia grandis L. on eight test plant species

Coccinia grandis L. (Cucurbitaceae) is a tropical vine that grows densely and suppresses the growth of surrounding plant species. The glabrous leaves and fruits of this plant have long been used as traditional medicine. The pharmacological property of C. grandis is notable, but as far we know there is no report on its allelopathic activity. To explore allelopathy (as an ecologically sound weed management approach), aqueous methanol extracts of C. grandis were examined for its effect on the seedling growth of cress (Lepidium sativum L.), alfalfa (Medicago sativa L.), rapeseed (Brassica napus L.), lettuce (Lactuca sativa L.), barnyard grass (Echinochloa crus-galli L.), timothy (Phleum pretense L.), foxtail fescue (Vulpia myuros (L.) C. C. Gmel.), and Italian ryegrass (Lolium multiflorum Lam.) at six concentrations (1, 3, 10, 30, 100 and 300 mg dry weight equivalent extract/ml). The growth inhibitory effect of the extracts on the test plant species varied and depended on extract concentration. The concentrations required for 50% growth inhibition of the shoots and roots of the test plant species were 6.3–220.8 and 4.8–80.9 mg dry weight equivalent extract/ml of C. grandis, respectively. The lettuce seedlings were most sensitive to the extracts, whereas the barnyard grass seedlings were least sensitive. These results suggest that C. grandis may have allelopathic potential and might be useful in developing a bio-herbicide in an eco-friendly management system.

Use of integrated weed management tools in crop rotations with grass seed production

ABSTRACTThis paper presents the results of studies quantifying the effect of some of the tools available in an integrated weed control strategy focusing on problematic annual grasses in crop rotations with grass seed production. The paper presents the results of experiments demonstrating the influence of competitiveness of the crop on the development of annual grass weeds. The experiments quantify the influence of establishment at different row distance, plant density, sowing depth and cultivar type. The paper further presents the results showing how a change in establishment time from autumn to spring influences the germination rate of four important annual grasses. The study demonstrated that springtime establishment offers the opportunity to reduce problems with Apera spica-venti and Poa trivialis and to a lesser extent with Alopecurus myosuroides and Vulpia myuros. The study further showed that the false seedbed technique can be a very effective tool to reduce problems with annual grasses. The populations of two of the investigated species, P. trivialis and V. myuros, were reduced by almost 80% applying the false seedbed technique. Dependent on the density and species composition of annual grasses expected these IWM tools can be used in strategies to secure a high quality in grass seed production.

Influence of different sludge compositions on understorey vegetation in an amended Pinus pinatser forest plantation

The present study reports on the influence of sludge application on understory abundance and species richness in an eight year-old maritime pine forest. Four types of sludge (liquid, dewatered, limed and composted sludge) were applied at a rate equivalent to 3 tons dry weight per ha−1 per year−1. Understorey vegetation was monitored before treatment and for three successive years following initial sludge application. Species richness, the biodiversity index and naturally occurring plant community cover in maritime pine forests were measured. Results showed a significant increase in species richness two years following initial sludge application. In fact, compared to the unamended plot, eighteen additional species (Aira caryophyllea, Cerastium glomeratum, Conyza canadensis, Danthonia decumbens, Geranium robertianum, Gnaphalium sylvaticum, Hypericum humifusum, Hypericum perforatum ssp. perforatum, Jasione montana, Lonicera periclymenum ssp. periclymenum, Ornithopus compressus, Phytolacca americana, Rhamnus frangula, Teesdalia nudicaulis, Veronica arvensis, Vicia sativa angustifolia and Vulpia myuros) appeared after sludge application. Most of these species were observed with the solid limed or composted sludge treatments. The new species then declined the following year, highlighting the temporary effect of sludge treatment on species diversity. However, the cover by these eighteen new species was low and did not exceed 1%, except for Hypericum perforatum and Jasione montana for the limed sludge treatment and Vulpia myuros for the liquid sludge treatment. Additionally, sludge significantly reduces bare soil percentage, which ranged from 5 to 18% compared to the control (38%). According to sludge type, treatment also led to a significant change in species dominance of the understorey plant communities. Indeed, the cover of Molinia caerulea decreased in spite of an increase in Agrostis capillaris and/or Holcus lanatus following application of solid limed, liquid or composted sludge.

Poa L. and Vulpia C.C. Gmel. (Poaceae): Two Generic Records for Andhra Pradesh, India

Poa L. and Vulpia C.C.Gmel. represented by Poa annua L., and Vulpia myuros (L.) C.C.Gmel. are reported as new generic records for the flora of Andhra Pradesh.

Effects of drought on weed emergence and growth vary with the seed burial depth and presence of a cover crop

In conservation agriculture, weed seed germination could decrease with the presence of a cover crop, surface weed seed location and temporal drought in summer just after seed shedding. This study simultaneously examined the effects of a cover crop, burial depth (seed location) and hydric stress on weed emergence and early growth. It was hypothesized that drought would reduce weed emergence and the initial growth of weed seeds and that this effect would be greater when the seeds were on the soil surface and in the presence of a cover crop. Four annual weed species were chosen that are frequently found (Anisantha sterilis, Vulpia myuros, Sonchus asper, Veronica persica) and not frequently found (Alopecurus myosuroides, Poa annua, Cyanus segetum, Capsella bursa‐pastoris) in fields that implement conservation agriculture. The unburied seeds had 26% lower emergence, on average, than the buried seeds (significant for six of the eight species), hydric stress reduced emergence by 20% (for seven of the eight species) and the presence of a cover crop reduced the level of emergence by 17% (for all species). The unburied seeds with hydric stress were emerging under the “most stressful” set of factors, with a 45% decrease in emergence, compared with the seeds emerging under the “least stressful” set of factors (buried seeds without hydric stress). All the weed growth measurements (height, dry matter content and number of leaves) decreased with the presence of a cover crop. The species that are found frequently in the fields that implement conservation agriculture, compared with the species that are not frequently found in conservation agriculture fields, had higher rates of germination and a higher tolerance of hydric stress when their seeds were unburied.

Phytotoxic effects of Cerbera manghas L. leaf extracts on seedling elongation of four monocot and four dicot test species

Exploration of allelochemicals with phytotoxic effects is intended to minimize a current dependency on synthetic herbicides in weed management. Several allelochemicals from the tropical tree <em>Cerbera manghas</em> (sea mango) have been reported as termiticides and bactericides. The present study investigated possible phytotoxic effects of <em>C. manghas</em> leaf extracts under laboratory conditions. Four monocots: barnyard grass (<em>Echinochloa crus-galli</em>), foxtail fescue (<em>Vulpia myuros</em>), Italian ryegrass (<em>Lolium multiflorum</em>), and timothy (<em>Phleum pratense</em>) and four dicots: alfalfa (<em>Medicago sativa</em>), garden cress (<em>Lepidium sativum</em>), lettuce (<em>Lactuca sativa</em>), and rapeseed (<em>Brassica napus</em>) were used as test species. Elongation of both shoots and roots of seedlings was measured to assess any phytotoxic effects. The results showed that the sensitivities of shoots and roots were different between the test species, and the inhibition of seedling elongation significantly increased with increasing concentration of leaf extracts of <em>C. manghas</em> for all the test species. The IC<sub>50</sub> (50% inhibitory concentration) values showed that 8.50–32.30 and 4.26–34.67 mg dry weight equivalent extract mL<sup>−1</sup> of <em>C. manghas</em> inhibited seedling elongation by 50%, for shoots and roots respectively. Isolation and identification of the phytotoxic substances from <em>C. manghas</em> are suggested for future investigation.

Reducing tillage intensity affects the cumulative emergence dynamics of annual grass weeds in winter cereals

SummaryAnnual grass weeds such as Apera spica‐venti and Vulpia myuros are promoted in non‐inversion tillage systems and winter cereal‐based crop rotations. Unsatisfactory weed control in these conditions is often associated with a poor understanding of the emergence pattern of these weed species. The aim of this study was to investigate, understand and model the cumulative emergence patterns of A. spica‐venti, V. myuros and Poa annua in winter cereals grown in three primary tillage regimes: (i) mouldboard ploughing, (ii) pre‐sowing tine cultivation to 8–10 cm soil depth and (iii) direct drilling. Direct drilling delayed the cumulative emergence of A. spica‐venti and V. myuros (counted together) in contrast with ploughing, while the emergence pattern of P. annua was unaffected by the type of tillage system. The total density of emerged weed seedlings varied between the tillage systems and years with a higher total emergence seen under direct drilling, followed by pre‐sowing tine cultivation and ploughing. The emergence patterns of all species were differently influenced by the tillage systems, suggesting that under direct drilling, in which these species occur simultaneously, management interventions should first and foremost consider that A. spica‐venti and V. myuros emerge over a longer period to avoid control failures.

温度,水の動態,老化指標,形態学的特徴に着目したナギナタガヤの倒伏特性

温度,水の動態,老化指標,形態学的特徴に着目したナギナタガヤの倒伏特性