Myuros Research Articles

The influence of nitrogen level, rainfall, seed pools, and pasture biomass on the botanical composition of annual pastures

The influence of nitrogen level, rainfall, seed pools and pasture biomass on the botanical composition of annual pastures was examined over five years at two sites at Baker's Hill in the south-west of Western Australia. At the first site a pasture that had declined in content of Trifolium subterraneum to 5% remained at this level over five years when receiving 100 kg ha-1 of nitrogen fertilizer. On plots not receiving nitrogen fertilizer, but grazed to the same level, Trifolium seedling numbers in autumn increased from 5 dm-2 to a maximum of 60 dm-2, but Trifolium content of the pastures in October only increased to 15%. At the second site, established pasture was resown to different annual pasture species. Plots resown to Trifolium had 30% of Trifolium in October of the reseeding year, but only 5% three years later. Trifolium seedling numbers in autumn were >70 dm-2 in three of four years. The Trifolium was replaced by Arctotheca calendula. Plots sown to Arctotheca maintained c. 50% of this species, whilst plots sown to Erodium botrys also maintained a high level of this species but had very little Arctotheca. Plots sown to the grass Lasiochloa echinata developed a progressively higher content of Arctotheca. Annual grasses (Bromus diandrus, Vulpia myuros, Hordeum leporinum and Lolium rigidum) occurred in all plots, but their contents showed no specific trend with time. The major species were found to have different adaptive characteristics. Whilst seedling number in autumn was a major determinant of the content of a species in the pastures in August, Trifolium content was enhanced by high autumn rainfall and low winter biomass. The contribution of each Trifolium seedling to clover content in August was much less than that of each Arctotheca seedling to the capeweed content at that time. The pasture composition in October was mainly determined by cornposirim in August, although heavy rain in October favoured Arctotheca and light rain favoured the grass species.

Selective regulation of germination and growth of annual weeds by crop residues

SummaryResidues from mature, harvested crops of sorghum (Sorghum bicolor Moench.), sunflower (Helianthus annuus L.), oilseed rape (Brassica napus L.), wheat (Triticum aestivum L.) and field pea (Pisum sativum L.), exhibited selective effects on weed germination and growth under field conditions. Weed species in the study included Avena fatua L., Avena sterilis ssp. ludoviciana (Durieu) Nyman, Echinochloa crus‐galli (L.) Beauv., Phalaris aquatica L., Phalaris paradoxa L., Lolium perenne L., Vulpia myuros (L.) Gmel., Hibiscus trionum L., Polygonum aviculare L., Bilderdykia convolvulus (L.) Dumort. and Lamium amplexicaule L. All crop residues tested, and in particular wheat and pea residues, promoted the germination and growth of A. fatua and A sterilis ssp. ludoviciana. Other grass weeds, however, were inhibited by the presence of crop residue, the extent of inhibition being dependent on residue type. Germination response of dicotyledonous weed species was also a function of residue type, H. trionum numbers were significantly higher in plots where oilseed rape, sorghum or sunflower residue had been incorporated, while L. amplexicaule was inhibited by these residue types and stimulated by pea and wheat residues.

Response of Monocotyledons to BAS 9052 OH

Postemergence applications of BAS 9052 OH, {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one}, at 0.25 and 0.5 kg ai/ha were made to 27 temperate and 28 tropical species ofGramineae. Annual bluegrass (Poa annuaL. ♯3POAAN) and rattail fescue (Festuca myurosL. ♯ VLPMY) were resistant to these rates of BAS 9052 OH. Five species of fescue and three species of bluegrass received postemergence applications of BAS 9052 OH at rates of 0.1 to 6.4 kg ai/ha. The germination of seeds and the subsequent growth of the seedlings of these species as influenced by various concentrations of BAS 9052 OH were also studied. Meadow fescue (Festuca pratensisHuds. ♯ FESPR), tall fescue (Festuca arundinaceaSchreb. ♯ FESAR), Kentucky bluegrass (Poa pratensisL. ♯ POAPR), and rough-stalked meadowgrass (Poa trivialisL. ♯ POATR) were most susceptible; annual bluegrass was somewhat less resistant; hard fescue (Festuca longifoliaThuill) was resistant; red fescue (Festuca rubraL. ♯ FESRU) and rattail fescue were very resistant.

Rotational vs. Continuous Grazing Affects Animal Performance on Annual Grass-Subclover Pasture

Rotational vs. Continuous Grazing Affects Animal Performance on Annual Grass-Subclover Pasture

Tiller Length vs. Tiller Weight: Applications to Plant Growth Studies

Tiller Length vs. Tiller Weight: Applications to Plant Growth Studies

Winter Annual Grass Weed Control in Italian Ryegrass with Ethofumesate

Ethofumesate (2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate) applied preemergence or early postemergence at 0.8 to 4.5 kg/ha eliminated annual bluegrass (Poa annuaL.) in Italian ryegrass (Lolium multiflorumLam.) seed fields. Rattail fescue (Festuca myurosL.) was more difficult to control. The 0.8 kg/ha rate controlled only 55% of the rattail fescue. Rates of 1.1 to 1.7 kg/ha controlled 72 to 95% and rates of 2.2 to 4.5 kg/ha eliminated rattail fescue. All ethofumesate treatments except one, 2.2 kg/ha applied postemergence in Experiment 7, reduced weed competition enough so that ryegrass seed yields were increased. At 4.5 kg/ha, a rate double that required to eliminate rattail fescue, seed yields were as high or higher than at 2.2 kg/ha rate, indicating that ethofumesate has at least a twofold safety margin on Italian ryegrass. The germination of ryegrass seed harvested from plots treated with ethofumesate at 0, 2.2, and 4.5 kg/ha was not affected by the treatments.

Response to nitrogen of three annual grasses

The responses of three annual grasses (Lolium rigidum, Vulpia myuros, and Hordeum leporinum) to nitrogen fertilizer were studied at three densities. Total herbage and nitrogen uptake were measured at four harvest dates. The response of the three grasses to nitrogen depended on their density. At low density both Lolium and Hordeum had greater dry weight increase than Vulpia, but at high density Vulpia responded as well as Lolium and better than Hordeum. By comparing the nitrogen responses at similar amounts of available herbage it was seen that, over a wide range of availability, both Lolium and Vulpia had greater absolute response than Hordeum. It was concluded that nitrogen response would probably be greatest on swards of Lolium or Vulpia that have a particular amount of available herbage.

A study of merino sheep grazing a bladder saltbush (Atriplex vesicaria) –cotton-bush (Kochia aphylla) community on the riverine plain

A study was made of Merino sheep grazing a bladder saltbush (Atriplex vesicaria Hew. ex Benth.)–cotton-bush (Kochia aphylla R.Br.) community set stocked at three stocking rates (2.5, 1 .2, and 0.6 sheep/hectare) over a 3-year period. In spring the sheep preferred the perennial grass Danthonia caespitosa Gaudich. and the annuals Medicago polymorpha L. and Vulpia myuros (L.) K. C. Gmel. to the more abundant A. vesicaria. From summer to early winter the diet consisted mainly of A. vesicaria with the proportion of dead matter and Medicago burr increasing as the availability of A. vesicaria decreased. Seasonal fluctuations in wool growth were evident at all three stocking rates. Maximum wool growth rates occurred in spring when the nitrogen content (2.3%) and in vitro digestibility (65%) of the forage eaten was high. During autumn and early winter values for nitrogen (1.4%) and digestibility (50%) were lower and wool growth was at a minimum. At 0.6 sheep/ha animal productivity was maintained and there was little decline in the A. vesicaria population during the 3 years. Grazing eliminated all the A. vesicaria from the pasture stocked at 2.5 sheep/ha, and 98% at 1.2 sheep/ha. At these higher stocking rates the pasture proved incapable of maintaining the sheep for the 3-year period. The inability of A. vesicaria to recover after heavy or complete defoliation by grazing demonstrates the necessity of adopting a low stocking rate if the bush is to be retained.

Saprophytic Survival of Ophiobolus Graminis on Various Hosts

Survival of Ophiobolus graminis on artificially infected straw of several hosts was studied under field and laboratory conditions over a period of 24 weeks. Survival, estimated by percentage of straws containing viable hyphae of O. graminis, was greater on barley than on wheat, Hordeum leporinum, Lolium rigidum, and Vulpia myuros. Survival was higher under laboratory than summer field conditions, and in the field was greater at 1 than at 6 in. below the surface; survival was increased under laboratory conditions by nitrate enrichment of soil

The effect of frequency and time of cutting on the production and quality of a barley grass (Hordeum leporinum) dominant pasture

A grazing experiment on a barley grass (Hordeum leporium Link) dominant pasture at Deniliquin, New South Wales, was carried out from May to November 1964. Monthly grazing of this pasture resulted in a greater dry matter yield of both green and total barley grass, and of crude protein, than when grazing occurred less frequently. The greatest stimulus to production was achieved when grazing occurred in August or September when the plants were approaching flowering. Rat's-tail fescue (Vulpia myuros (L.) K.C. Gmel), the other main component of the pasture, was not stimulated to greater total dry matter production by increasing the frequency of grazing. However, significantly more green fescue was harvested from areas grazed most frequently. The quality of both species, as estimated by nitrogen content and in vitro digestibility of barley grass and nitrogen content of fescue, was higher late in the season on the monthly grazed areas than on areas grazed less frequently.

Selective Control of Downy Brome and Rattail Fescue in Irrigated Perennial Grass Seed Fields of Central Oregon

Selective Control of Downy Brome and Rattail Fescue in Irrigated Perennial Grass Seed Fields of Central Oregon

Studies of the Kinds of the Weeds of Arable Land in Japan and Their Geographical Distributions : VI. The origin and history of Japanese weeds

In this study about the weeds on arable lahd in Japan, the following five groups were suggested from their present geographical range, though it must be admitted that we cannot show their origin exactly. The historical consideration has also been given in this paper. 1) The recently naturalized plants have been introduced in recent year. 2) The old naturalized plants were introduced from Europe or Eurasia through China in the early stage of history. 3) Cosmopolitan. 4) The prehistoric naturalized plants were introduced from Central and South China in ancient times. 5) Native species. 1) The recently naturalized weeds on upland field : 27 species were originated from Europe, and some of the most important are as follows; Senecio vulgaris, Veronica arvensis, Cerastium visosum, Rumex Acetosella, Festuca Myuros, etc.; 5 from Eurasia, Veronica persica, etc.; 9 from Nouth America, Erigeron annuus, E. canadensis, Euphorbia supina, Oxalis Martiana, etc.; 6 from New Tropical regions or South America, Oenothera odorata, Amaranthus retroflexus, etc. 2) The old naturarized weeds: 8 species were originated from Europe. Sonchus brachyotis, Vicia sepium, V. tetrasperma, Stellaria neglecta. Polygonum nodosum, P. Persicaria, Poa annua and Polygonum lapathifolium. All these species are upland field weeds, except the latter one which is paddy field weeds. 25 species were originated from Eurasia, among them Galium spurium, Elsholtzia patrini, Lamium amplexicaule, Capsella Bursa-pastoris, Chenopodium album, etc., are in upland field, whereas the following 13 species are in paddy field, Elatine triandra, Cardamine flexuosa, Ranunculus sceleratus and the others. 3) The species of old world origin or Cosmopolitan; 27 species on upland are Stellaria aquatica, Bulbosylis barbata, Digitaris adscendens, Equisetum arvense, 0xalis corniculata, Portulaca oleracea, Amaranthus ascendens, Polygonum aviculare, etc.: 26 are found in paddy field, among them there are Bidens tripartita, MyrioPhyllum verticillatum, Nasturium palustre, Eleocharis acicularis, Hydrocharis asistica, Ceratophyllum demersum, Najas marina, etc. 4) The prehistoric naturalized species: They are originated from South eastern Asia and especially interesting because these weeds are attendant on rice plants. Among them, Eclipta alba, Dopatorium junceum, Lindernia angustifolia, L. Pyxidaria, Limnophila sesseliflora, Ludwigia prostriat, Rotala indica, Monochoria vaginalis, Eriocaulon sieboltianum, Cyperus diffomis, C. Iria, Fimbristylis miliacea, Echinochloa crus-galli var. oryzicola. etc. are most important. 5) The Japanese native species; there are endemic species and the mutual common species in Japan, Korea, China, or Siberia, etc. The former contains only two species; Pleioblastus spp. and Sagittaria Aginashi. The latter would be perhaps the native species in those days when Japanese archipelago was detached from the continent (the last part of Diluvial epoch or the early years of the Allucual epoch) The native species which can be seen in Eastern as well as Northeastern Asiatic continent are amounted about 130 species on upland field and about 90 on paddy field. The most species, however, are slightly harmuful weeds, i.e., they are grown on the bordering foot-path or in the edge of irrigation ditches. A few species are noxious. As mentioned above, most of the troublesome weeds in Japan were found among the foreign species

The Return of Native Perennial Bunchgrass Following the Removal of Klamath Weed (Hypericum Perforatum L.) by Imported Beetles

During the relatively short period of 4 years since release of imported beetles which feed on it, Klamath weed, HypericUri perforatiun, a serious weed on perhaps a million or more acres of Western range lands, has been brought under strikingly successful control in limited areas by this tool of applied ecology. Though the range in queston has not yet been put under normal grazing, the rapidity and vigor with which the climax hunchgrass, Dantho nia californica, entered the space vacated by the removal of Klamath weed by beetles of the genus Chrysomuiela (= Chrysolina), promises much for the more favorable locations in Humboldt and possibly Menclocino, Trinity and Siskiyou counties in California. The initiation of quantitative studies designed to follow the pattern of vegetational changes and the correlated beetle populations was reported by Iluff aker and Holloway (1949). A brief review of an important survey of these counties by Davy (1902) indicates: 1) The climax grass cover in this area probably consisted of Danithonia californica as the most important component. Other bunchgrasses such as Stipa, Melica, Elymus, Poa, and Festuca were represented, as were important associated forage species such as Trifoliuml spp. (annual and perennial clovers), Lath yrus spp. (wild pea vines), and Wyethia sp. (wild sunflower). 2) There were important early changes, apparently beginning with invasion of the region by such introduced annuals as Erodiumt cicutarpum (filaree) and Avenia fatua (wild oats), later followed, as a result of still heavier stocking, by Hordewun gussoneanum (foxtail), Festuca myuros (rat-tail fescue), and Browrus hlordeaceus (soft chess), and still later by the appearance of weedy arrivals during the last years of the past century. such as Erodium moschatum (musky filaree), Brownus rigidus (broncho grass) Hordeum murinumn (foxtail), Centaurea melitensis (tacaloti), Hypochoeris glabra (hawkbit), and Medicago hispida (burclover). The latter species and the filaree are considered of definite forage value. Some comparison of Davy's survey with the present quantitative results may be worthwhile. For example, Hypochoeris glabra was at that time making its appearance, but now is a definite pest. Also, E. cicutarium, the filaree which thrived prior to his study, is definitely not the species of Erodiurn now most common in either that area or at the 1 Presented in general terms, with slides, at the Western Section Meeting of the Ecological Society at Salt Lake City, June 22, 1950. The general project is under the coordinating supervision of J. K. Holloway and is a cooperative one under the direction of Professor H. S. Smith of the Division of Biological Control, University of California and C. P. Clausen of the Bureau of Entomology and Plant Quarantine of the U. S. Department of Agriculture. The author wishes to express appreciation for the cooperation and assistance given this work by the Division of Agronomy of the University of California, and to acknowledge particularly the help of Professor Ben A. Madson and A. H. Murphy. The detailed program of importation of the beetles, their distribution to the Klamath-weedinfested areas and the general progress of control of the weed, as distinct from this study of the associated vegetational changes in the specific study areas, is reported by Holloway and Huffaker (1951).