Weed Science Commons^™

Pasture Plant Identification In The Western Queensland Arid Zone, J A. Milson, I F. Beale, J A. Reynolds, J J. Bushwell, D Phelps

IGC Proceedings (1977-2023)

Since plant species composition is an important indicator of the health or condition of pastures and therefore the land, a first step for graziers interested in conserving the total range resource is to understand vegetation species and thus be able to identify them and to recognise species changes. This project is aimed at producing and distributing colour leaflets of the major native and problem plant species (including woody weeds) in the four major community types in western Queensland. The number of colour leaflels for the series totals 60. The number of species represented is about 230. These leaflets are dislributed …

Farm Monitoring, A Way To Improve Performance On Sheep And Beef Farms, R W. Webby, G W. Sheath

IGC Proceedings (1977-2023)

A programme that centres on monitoring the performance of sheep and beef farms is being used to encourage farmers to make decisions based on objective measurements, Monitor farmers are supported by their farming peers in groups that include extension and science personnel. Key biological performance indicators such as animal numbers, weights; weight gains, pasture production; and financial returns from meat and wool are monitored. Farmers are encouraged to be in a position to use this information and identify opportunities. Processors of sheep and beef products are demanding the production of livestock to tighter specifications. Close monitoring by farmers will be …

Use Of A Model To Investigate The Profitability Of Fertilizer Application, T.J M. Johnston, D G. Mccall, P R. Marshall

IGC Proceedings (1977-2023)

Use of a model to investigate the payback to alternative phosphate (P) fertiliser programmes is described. Input for the model is fertiliser history (kg P/ho/year) over 5-15 years. A site fertility index is established by summing discounted P applications. The index is related to relative pasture yield (annual yield/non P limited yield) for a soil type. The economics of P use are evaluated by scaling current gross margin/ha for changes in relative pasture yield and subtracting fertiliser costs. The model provides the decision maker with yearly cashflow information and a I 0-year net present value (NPV) analysis of the relative …

Wild Parsnip (Pastinaca Sativa) Identification And Control In Residential Landscapes, Michael Caron, Taun Beddes, Corey Ransom

All Current Publications

Wild parsnip is a weed that can potentially cause serious injury to gardeners. This fact sheet describes this weed, its lifecycle, and suppression and control options.

What Is The Best Fit For Electric Weed Control In Australia?, Miranda J. Slaven, Catherine Borger

Experimental Summaries - Plant Research

Electric weed control is a non-chemical weed management alternative that will apply to a range of agricultural systems. The current project assessed electric weed control via the continuous electrode-plant contact method (using a Zasso™ XPower).

A wide range of field trials in 2022 and 2023 investigated weed control efficiency, suitability of electric weed control for fence line control of glyphosate-resistant annual ryegrass (Lolium rigidum Gaud.), use for crop topping, fire risk, damage to the soil biota, or use for inter-row weed control in vineyards or lupin crops. Broadleaf weeds were controlled more effectively than grass weeds with electric weed …

Effect Of Chemical And Mechanical Weed Control On Weed Seed Banks In Rice Field, Uum Umiyati, Dedi Widayat, Yani Maharani

Jurnal Kultivasi

Weed control is essential for ensuring the diversity of weeds on agricultural land. A study was conducted in rice fields in Subang and Cianjur districts, where 24 fields were observed to have varying weed management approaches. The research employed descriptive methods, including surveys to identify weed types and destructive methods to analyze weed seed banks at different depths. The descriptive methods included surveys to identify weed types and destructive methods to analyze weed seed banks at different depths. Each district contained twelve rice fields that reflected diverse environmental conditions and weed control techniques, yet shared a similar age range of …

Effects Of Cutting Management On Herbage Production And Tiller Population In Smooth Bromegrass (Bromus Inermis Leyss), J X. Xia, J Hodgson, A.C P. Chu, P Wang, F Y. Liu

IGC Proceedings (1977-2023)

This paper reports the results of an experiment with smooth bromegrass (Bromus inermis Leyss) under cutting management at Beijing Agricultural University, China from June-October 1989. The main treatments were cutting intervals (l month v. 2 months) and cutting height (10 cm v. 30 cm) with 2 additional treatments (uncut control, and delayed first cut) and 4 replications. Frequent cutting decreased tiller population density, herbage accumulation and underground biomass. Tiller populations were greater under lax than hard cutting, though closer cutting resulted in greater green herbage accumulation. Delaying cutting until flowering was completed resulted in a subsequent depression in herbage …

Relative Productivity And Persistense Of White Clover Cultivars Under Cutting Or Continuous Stocking By Sheep, D A. Davies, M Fothergill

IGC Proceedings (1977-2023)

Perennial ryegrass-white clover (Lolium perenne-Trlfollium repens) swards of 3 clover cultivars were studied at a lowland (30 m) and upland (340 m) site in mid Wales over 3 years (1989-91). Lamb production from small-leaved Aberystwyth S 184 at 1021 kg/ha was 25% and 1191, more than from small-leaved Ac3351 and medium-leaved Grasslands Huia respectively. The relative lamb output from Huia was poorer at the upland location. Clover production, survival and morphology under a number of cutting heights and frequencies were different from those in the continuously stocked pastures. Cutting every 10 days at 2-3 cm resulted in poor clover and …

Morphological Changes In Three Clover (Trifolium Repens L.) Cultivars Under Continuous Stocking, M Fothergill, D A. Davies

IGC Proceedings (1977-2023)

Individual plant morphology of 3 white clover (Trifolium repens L.) cultivars was studied during 1990 and 1991. Seasonal shifts were demonstrated by all cultivars towards a higher proportion of less complex plants from winter to mid summer. Over the latter half of the year the population tended lo return towards its original distribution. Seasonal fluctuations in stolon dry weight/plant and root number/plant were also identified, with the small-leaved Ac3351 maintaining a greater stolon OW/plant than Aberystwyth S184 and Grasslands Huia during 1990. Ac3351 and S184 also maintained a larger root number/plant over this period. However, no significant differences were detected …

Response To Defoliation Of Tall Fescue, H Tavakoli, J Hodgson, P D. Kemp

IGC Proceedings (1977-2023)

An experiment studying the behaviour of toll fescue (Fesutca anrundinacea Schreb,) was conducted under steady stale grazing on a sward dominated by this plant. The swards were grazed lo maintain a surface height of 30-40 mm (H), 50-60 mm (M) and 90-100 mm (L). These treatments were applied on swards with and without white clover (Trifolium repens L.) from November 1990 to April 1991. Results showed that leaf growth decreased as the severity of grazing increased. Tiller number was less under H grazing than under M or L grazing, but tiller size remained constant over time in this …

Carbon Isotope Discrimination And Productivity Of Yellow-Flowered Falcata Alfalfa Clonesj, J A. Morgan, D R. Lecain, C E. Townsend

IGC Proceedings (1977-2023)

Although genetic variation for water•use efficiency has been identified in a number of plant species, progress to genetically increase this trait has been limited, largely owing to the difficulty in evaluating numerous genotypes. Eleven clones of yellow-flowered, falcata-type alfalfa (Medicago saliva L. ssp. falcata (L.) Arcangeli} were grown in the greenhouse under 2 watering regimes, and in space•planted field plots for 2 years. Clonal variation was found in all 4 environments for plant yield and shoot carbon isotope discrimination (A), a trait believed to estimate plant water use efficiency. Generally non­significant correlations between A and forage yield suggest that …

Adaptation Of Sainfoin Cultivars And Lucerne To Water Stress, S R. Mir Hosseini, P D. Kemp, D J. Barker, J Hodgson

IGC Proceedings (1977-2023)

Sainfoin ( Onobrychis viciifolia Scop.) is of particular interest as a pasture crop because it is a productive legume in dry areas but does not induce bloat in ruminant animals. In this study 3·sainfoin cultivars (Fakir, Melrose and 035) and l lucerne (Medicago saliva L.) cultivar Grasslands Oranga were compared during a drying phase when water was withheld once; flowering began. A randomised complete block design with 4 replicates' was used. Transpiration rate (Tr) declined as volumetric soil water content (VSWC) was reduced. Stomata! resistance (Rs) increased and relative ivater content (RWC) decreased when VSWC decreased. Critical VSWC for …

Phytochrome Control Of Assimilate Partitioning In White Clover, Ch Robin, C Varlet-Grancher, F Gastal, A Guckert

IGC Proceedings (1977-2023)

Experiments were conducted in controlled conditions to examine the influences of phytochrome on assimilate partitioning between stolons and branches and to determine the effects on plant moq>hogcncsis in white clover (Trifolium repens L.). Far-red (FR) irradiated plants partitioned more 14C-assimilates to petioles of both the main stolon and branches and less to the nodulated COOis than did control plants. Results clearly demonstrated that FR-irradiated plants developed longer petioles and long internodes. Moreover, the branching rate decreased, which induced a lower portion of dry weight allocated to branches. However, the sink strength of the branches which were developing remained …

Influence Of Rooting On Stolon Branching In White Clover, M Jones, N R. Sackville Hamilton

IGC Proceedings (1977-2023)

The relationship between rooting and branching in stolons of white clover (Trifolium repens L.) was investigated in a field experiment, Half of a group of stolons was allowed to develop roots naturally, while for the other half root establishment was prevented by severing young roots before they made contact with the soil. Prevention of root establishment did not affect the numbers of branches which developed on nodes produced during the experiment, and it stimulated of branching on nodes which were already present. This result was unexpected on the basis of earlier observations of stolon growth and suggests that the …

Accumulation Of Dry Matter, Protein And Total Available Carbohydrate In Berseem Under Different Cutting Regimes, P Martinello, G De Santis, A Iannucci, N Di Fonzo

IGC Proceedings (1977-2023)

The effect of different cutting regimes on physiology and morphology of aerial parts and roots in 6 bcrseem (Trifolium alexadrium L.) genotypes was evaluated. Observations were carried out on individual plants at 4 stages of development: fourth and eighth internode elongation, early flowering and physiological seed maturity. The results showed that the genotypes were characterised by highest values of dry matter in the aerial and root parts at the early flowering stage. Variability among genotypes was observed.

Seasonal Growth Rhythms In Lucerne, C Poisson, G Genier, A Canal, P Guy, A Porcheron

IGC Proceedings (1977-2023)

The repartition of dry matter production of lilcerne (Medicago saliva) through the year is of great interest. A 3-year experiment began in 1990 to distinguish different rhythms of regrowth. Eighteen genotypes of very diverse geographic origins exhibiting great differences of winter dormancy were studied in a multisite experiment. Two different non-destructive methods were used to describe accurately leaf area index evolution: red far/red light ratio (660 nm/730 nm), and indirect measurement of LAI {LI-COR 2000); stem height and dry matter yield were regularly recorded. Important differences in summer and autumn behaviour leading to different sigmoid growth curves wece …

Inherent And Realized Potential Of Axillary Buds Of White Clover In Field Populations, P.C D. Newton, M.J M. Hay

IGC Proceedings (1977-2023)

Fewer than 10% of while clover (Trifolium repens L.) axillary buds form established branches in grazed swards. In order to understand the mechanisms controlling his large loss of growth potential we have charted the potential fates a bud may meet. Each step in this flow chart offers the possibility for a loss of branching potential. We consider the factors that may be important in determining the fates of buds and highlight in particular the heavy losses of viable buds at a young age and propose that different factors may control branch initiation and branch establishment.

Prediction Of Plant Mortality Under Grazing- A Conceptual Approach, J J. Mott, G K. Mckeon, K A. Day

IGC Proceedings (1977-2023)

Based on the concept of biological thresholds, there is growing acceptance 0£ the importance o£ episodic events in the determination of rangeland condition trend. The variable rainfall occurring within Australian rangelands means that overstocking during droughts is a major cause of these Australian rangeland vegetation complexes exceeding these thresholds. Recently plant production models and simplistic estimates of the relationship between animal utilisation and plant mortality became available. Accurate estimates will be developed only with the incorporation of a sound mechanistic understanding of the relationship between utilisation of forage and plant mortality for different conditions of species and soils. Detailed studies …

Canopy Structure And Forage Production Of Lolium Rididum Gaudin As Influenced By The Frequency Of Defoliation, P P. Roggero, A Franca, M Sitzia, S Caredda

IGC Proceedings (1977-2023)

An experiment was conducted in Sardinia to develop an appropriate rotational grazing management regime in spring for an ecotype of annual ryegrass (Lolium rigidum Gaudin). Three intermittent defoliation treatments were compared using sward surface height (10, 15 or 20 cm) to determine time of cutting. Forage dry matter yield, tiller population density, LAI, vertical distribution of plant tissues and other related characteristics were measured. Cutting when sward reached 10 cm resulted In significantly lower yields but a better canopy structure (denser sward, higher percentage of leaves in the bottom layers, higher leaf: sheath ratio) than the other treatments. The …

Physiological Response And Leaf Production Of Two C4 Grasses After Small Rainfall Events, A J. Norman, T L. Thurow, C A. Taylor Jr

IGC Proceedings (1977-2023)

The response of plant water status and leaf production of sideoats grama (Bouteloua curtipendula Michx.) and curly mesquite (Hilaria belangeri Steud.) to application of 10 mm of water were studied in 6 continuous weighing lysimeters near Sonora, Texas, USA.: Transpiration, stomata! conductance, xylem water potentials and leaf production were measured foe both species. Soil water content was monitored in each lysimeter. The 10-mm simulated rainfall events improved plant water status regardless of prior soil water· content.' The transpiration rate for both species was similar. Stomata! conductance' of B. c1irtipe11d11/a responded faster after the simulated rainfall events. More favorable …