Weed management

1. Introduction

Soybean crops have poor tolerance for weed competition, particularly when small. Even moderate, uncontrolled early weed pressure will dramatically reduce yields. High weed pressure also adds to harvesting costs as weeds at crop maturity can delay harvest and block machinery. Grading out weed seeds from contaminated grain will incur additional costs and may even make the grain unsaleable.

Early weed control is critical to optimise yield, as young soybean plants are at their most vulnerable up to 6–7 weeks from sowing. Ideally, choose a field with a known low weed seedbank pressure that has been in rotation with other winter and summer crops. It is inadvisable to plant soybean into any block with a history of high broadleaf weed pressure, as there are limited robust broadleaf herbicide options for use in soybean crops.

Once established, soybean crops are effective at providing crop competition for low growing weeds due to their dense canopy (typically from around 6–7 weeks post planting), however, it is unwise to expect that the soybean crop will ever out compete weeds without any external management. 

2. Effects of weeds on soybean production 

Weeds compete with soybean crops for moisture, nutrients, and light. Weed contamination of the crop can drastically reduce grain yield and increase harvest costs from mechanical complications and blockages. Further costs may be incurred if weed seeds must be graded out of harvested grain. 

Tall growing weeds (e.g. apple of Peru, gooseberries) that push through the crop canopy can shade the crop, causing leaf fall and straggly, weak stemmed plants with low pod counts. Under cool humid conditions these crops may also be more likely to develop sclerotinia disease. 

Early weed control is critical to optimise yield, as young soybean plants are at their most vulnerable up to 6–7 weeks from planting. Research conducted at University of Queensland, Gatton (Rasool, et. al., 2017) compared soybean yield from 25 cm and 75 cm row spacing where Rhodes grass was established with the crop; at 3 weeks after planting (WAP); at 6 WAP; and in a weed–free control crop (Figure 1).

This research shows that uncontrolled weeds allowed to establish at planting are likely to result in 75–95% yield loss, while keeping the crop weed-free for 6 weeks after planting reduced yield loss from weeds to approximately 10% when grown on 25 cm row spacing and to around one third for 75 cm row spacing. https://www.publish.csiro.au/CP/CP17229  

Key weeds of soybean crops

• Barnyard grass, crowsfoot grass, Bathurst burr, blackberry nightshade and bladder ketmia are present in most growing areas and will vigorously compete with the soybean crop. Bathurst burr and blackberry nightshade are seed quality contaminants. 

• Feathertop Rhodes grass, common sowthistle and flaxleaf fleabane are increasing in prevalence, especially under no–till/minimum–till farming systems. 

• Vines (e.g. bellvine) are major problems in coastal soybean crops grown in cane farming rotations due to their weed competition effects and their vigorous twining habit, which may prevent harvesting of the soybean crop.

• Uncontrolled growth of troublesome weeds such as apple of Peru, jute and sesbania pea can prevent harvesting because of their tall growth habit.

• Legume weed species (e.g. phasey bean) and sesbania pea can be very difficult to control in soybean crops due to a lack of effective herbicide options. Legume weeds may also host pests that affect soybean crops e.g. soybean stem fly (Melanagromyza sojae).

3. Integrated weed management

The principle of integrated weed management (IWM) is that crop weeds are managed most effectively using a combination of chemical and non-chemical methods. Good weed management relies on crop rotations and specific management strategies targeted at reducing the seedbanks of problem weeds. 

Integrated weed management will also delay herbicide resistance. The integrated WeedSmart Big 6 principles for resistance management are:

1. Rotate crops and pastures

2. Double knock – e.g. to slow resistance development for glyphosate and Group 1 herbicides

3. Mix and rotate herbicides

4. STOP weed seed set

5. Increase crop competition

6. Implement harvest weed control. 

Additional components of an effective IWM strategy include:

• Identify weeds and understand their biology to implement the most effective tactics for key weeds.

• Plan weed management strategies and control weeds before planting.

• Select row spacing and planting rate to enhance crop competition and use inter-row cultivation to reduce reliance on in-crop herbicides.

When using herbicides:

• Always read the herbicide manufacturer's product label before use.

• Apply herbicides at the right time and at the right rate.

• Use effective application equipment.

• Keep accurate records.

An important approach of IWM is to look at the farm as a system and to control weeds before you plant.

For further information view the soybean IWM webinar on coastal weeds on the ICAN website.

4. Managing the weed seedbank

Weed control starts with a program to manage the weed seedbank in the soil. As no single herbicide or management option will control all weeds, growers should be conscious of the importance of crop rotations to reduce the weed seedbank of key weed species and provide a more diverse range of weed management options. 

For example, when soybean is grown in rotation with maize, this allows the use of a range of effective herbicides to control problem broadleaf weeds in the maize crop and thus may reduce the broadleaf weed seedbank for the following soybean crop. Similarly, an effective grass weed management program implemented in a green cane trash blanket system should reduce the grass weed seedbank, which will benefit the following soybean crop. 

For weeds such as phasey bean, sesbania pea or vines, where there are very limited herbicide options in soybean, it is critical to ensure that these are well managed by not allowing any seed set in the last couple of years of the preceding cane (or other) crop. 

Most of the key grass weeds have relatively short seed persistence, especially when left on the soil surface in a no-till farming system. For many grass weed species, if weed seed production can be totally eliminated for 2–4 years, the seedbank will be significantly exhausted. ‘Surface germinating’ broadleaf weeds such as fleabane and sowthistle also have a relatively short seedbank life. 

However, many larger or hard seeded broadleaf weeds, (often includes seeds in pods), may persist in the soil as viable seed for many years. This long seedbank persistence makes it more difficult to successfully implement management strategies that are based on seedbank elimination and places even more importance on stopping weed seed set in the first place.

Farming systems dictate weed problems! 

Where growers move to a no–till farming system, it is typical to start to observe a significant shift in weed species within 3–5 years. ‘Surface germinating’ species such as feathertop Rhodes grass, fleabane and sowthistle are likely to start to dominate where cultivation has been removed from the system. These ‘surface germinating’ species typically produce large numbers of small seeds. The small seed size means that they are generally unable to emerge from depth if buried, while also having relatively short persistence on the soil surface. These species compensate by producing very high quantities of seed if allowed to set seed.

In contrast, in systems where cultivation is regularly used a broader mix of weed species is more likely to persist, in particular, weed species that are capable of emerging from depth. For most species, burying weed seed to the depth of normal tillage extends their seedbank life, especially for larger seeded species and/or those with hard seed coats.

For no-till farming systems, the longer-term goal should be to deplete the weed seedbank over time by ensuring that no weeds are allowed to set seed. This objective will be harder to achieve in a cultivation-based system.

5. Methods of weed control

A well-managed, weed-free fallow is the essential first step for good weed management. Typically, this is achieved by using cultivation or herbicides. 

5.1 Cultivation

With cultivation, a weed-free seedbed is best achieved with an early working and follow-up cultivations to help kill weed transplants and remove successive germinations of seedlings. In coastal farming systems where it is not always possible to apply herbicides at the correct growth stage due to weather limitations, cultivation may sometimes be a preferred option on larger weeds.

However, tillage comes with the downside of burying weed seeds and prolonging seedbank life. Redistribution of weed seeds across the depth of tillage may also reduce the effectiveness of some ‘low-mobile’ pre-emergent herbicides.

Full cultivation is falling out of favour in many areas as it doesn’t align with soil and moisture conservation philosophies. The widespread availability, adoption and price reduction of autosteer GPS across much of the grains industry has meant that more growers are adopting reduced and no-tillage systems. 

5.2 Crop competition

The early development of a dense crop canopy will greatly reduce the impact of weeds germinating later in the season (Figure 2). However, crop competition alone will not compensate for poor (or absent) weed management, especially where weeds establish early in soybean crops. Establishing a uniform, robust plant stand at the targeted plant population is an important step in minimising gaps in the crop, which allow weeds to flourish. 

Sowing too deep, into compacted, crusted or waterlogged soil are all factors that can reduce establishment and increase weed competition – this is discussed in Module 5–Agronomy?. Cool soil temperature at planting can also delay vigorous crop establishment, especially where the soil is also waterlogged. 

Early canopy closure is best achieved by sowing in narrower rows, however this may not suit farming and harvesting systems set up for other row crops like cotton, maize and sugarcane. Conversely, wide rows allow inter-row cultivation and the possibility of inter-row spraying using shields.

Research has shown that changing plant population (but maintaining the same row spacing) has less impact on weed competition in soybean than using narrow row spacings. Decisions around plant density should be primarily based on variety recommendations, yield expectations and available soil moisture, rather than a weed-competitive outcome.

5.3 Herbicides

In most commercial soybean growing operations, herbicides are essential tools for cost-effective weed management. 

Key considerations for effective herbicide use:

• It is more reliable and usually cheaper to control weeds before they emerge, or when they are small. 

• Read the herbicide label carefully for details on application rate for the weed size, application methods including required spray quality, water rate and adjuvant (if needed), conditions for spraying and the appropriate personal protective equipment (PPE) required to safely mix, load and apply.

• Time prior to rainfall can be an important consideration for coastal farming systems. Refer to the rainfast period on the label when rainfall is possible within hours of application. 

• Use the correct adjuvant for the individual herbicide. The label will explain when additional adjuvant is required and which type to use. If no adjuvant is recommended, then it is unlikely that a tank-mixed adjuvant will improve efficacy or rainfastness. Adding the wrong type of adjuvant may reduce control. 

• Always use good quality, clean water.

• Make sure application equipment is appropriate for the job, is well maintained and accurately calibrated. 

• All nozzles wear out and need regular replacement. Nozzle lifespan will depend on the construction material and also the type of pesticides used. For example, a low-cost plastic nozzle regularly putting out abrasive wettable powder or some granular formulations may need replacing every few months. 

For most farms, at least two sets of nozzles will be required:

• One set of nozzles that produce a Medium to Coarse spray quality, which should be used for ‘coverage sensitive’ herbicides such as paraquat, Group 1 and Group 14 herbicides. This nozzle is also most likely the preferred nozzle for many fungicides and insecticides.

• One set of nozzles that produce a Very Coarse (or larger) spray quality, which should be used for translocated herbicides such as glyphosate or Group 4 herbicides and pre-emergent herbicides. This nozzle should also be used for all applications upwind of any drift-sensitive areas. 

Soybean can be particularly sensitive to spray tank residues of some herbicides used in sugarcane or fallow, and very thorough boom sprayer decontamination is recommended before first in-crop use. 

When decontaminating a boom spray, always remove and clean all nozzles and in-line filters. This is a good time to check nozzle wear and replace used nozzles. 

For more information on boom spray decontamination. 

For more information on nozzle cleaning.  

GRDC has a many useful resources for spray application: 

• Spray application manual 

• Nozzle Selection for boom, band and shielded spraying 

• Nozzle selection chart 

• Weather essentials for pesticide application  

• Spray drift 

Herbicide resistance

Weeds will become resistant to herbicides in systems where herbicides are relied on for weed control. Resistance selection occurs faster when a limited number of herbicides are overused, and especially if strategies are not in place to control survivors. Follow the WeedSmart Big 6 by practicing good crop rotations, mix and rotate herbicide mode of action (MOA) groups, stop weed seed set, use crop competition, and combine chemical and non- chemical weed control methods to slow the selection of weed resistance.

Herbicide resistance to glyphosate is now common in an increasing number of weed species. These include barnyard grass, liverseed grass, feathertop Rhodes grass, sweet summer grass (Central Qld. only), fleabane and sowthistle throughout the cropping areas of Queensland and northern New South Wales. 

In addition, while currently the number of populations is low, resistance to haloxyfop (e.g. Verdict®) has been confirmed in crowsfoot grass and to paraquat in crowsfoot grass, blackberry nightshade and cudweed from coastal Queensland farming systems.

If herbicide resistance is suspected, it is important to have populations tested, both to confirm it is resistance, but more importantly to check what still works. If you don’t test, the next herbicide you use may or may not work, or you may make an erroneous decision to not use a particular herbicide when indeed it still has useful efficacy. Either way, if you don’t test, you lose! 

When testing for resistance, test the efficacy both of the product that has failed as well as other products you may use in its place. It’s important to know if resistance is present and if it is, does it confer cross-resistance to other products or not.

While some resistance tests for grass weeds can be done on live plant samples (for quick turnaround), most resistance testing requires collection of mature viable seed and has a turnaround time of several months. Seeds for resistance testing can be sent to either:

Charles Sturt University (Wagga Wagga, NSW) or Plant Science Consulting (Prospect, SA).   

Details on the cost of resistance tests and sample collection process can be found on the respective web sites.

The WeedSmart website has additional information on herbicide resistance and resistance testing.   

Weed-free fallow

It is important to ensure that the paddock is weed-free at planting.

In a reduced or no-till situation, one or more herbicide applications are used to control fallow weeds. Often there is high reliance on glyphosate, with multiple applications commonly used. Over multiple seasons, this places a high selection pressure for weeds to develop resistance to glyphosate. 

The inclusion of a ‘double knock’, where a systemic herbicide e.g. glyphosate (e.g. Roundup®) is then followed approximately 7 days later by a contact herbicide e.g. paraquat (e.g. Gramoxone®) is a very effective strategy to both improve the level of control of many fallow weeds, while also being a very useful resistance management option to slow the development of resistance and prolong the effective life of glyphosate. Depending upon the species requiring control, a tank-mix partner herbicide may sometimes be added to either pass.

Including a residual herbicide into the program can reduce the required number of knockdown applications in fallow. Residual herbicides can be particularly useful in periods of frequent rainfall where it may not always be possible to apply knockdown herbicides on time. Where residual herbicides have been used in the lead up to soybean planting, it is important to ensure that all plant back requirements specified on the registered product label are met.

Residual herbicides require good soil coverage. If paddocks are weedy at application, then a significant percentage of the applied residual herbicide may be intercepted and taken up by the weeds and never reach the soil. Additionally, if the residual herbicide is not water-soluble and binds strongly to organic matter, then subsequent rainfall may not wash it off the stubble and into the soil. These factors can lead to reduced residual control of weeds. Where weed density is high, best results will normally be achieved by delaying application of the residual herbicide until after knockdown of the existing population. However, in lower weed densities it may be adequate to mix the residual herbicide with a knockdown application, particularly in the second pass of a double knock program.

The information presented in Tables 1 to 6 is correct at July 2023, however, growers must follow label instructions and consult with their local agronomists for up to date advice on chemical choice.

Residual herbicides at planting

Uncontrolled weeds compete strongly with young soybean plants, resulting in substantial yield reduction and potential harvest difficulties. Residual herbicides are an important tactic to ensure the crop is kept weed-free until canopy closure, after which the crop is better able to compete with later weed germinations.

Depending upon the individual herbicide, residual herbicides may be applied before planting (pre); post-sowing but pre-emergent of the crop (PSPE); or early post-emergent (EPE).

Section 6 provides additional information on weeds controlled.

Knowing the position of the weed seeds in the soil profile is important when selecting a pre-emergent herbicide. Where cultivation has been used in the preceding years, weed seeds will be mixed in the soil at a range of depths. 

• Trifluralin and pendimethalin have very low soil mobility and will not move through the soil profile with rainfall. Labels suit use in a full cultivation farming system, requiring a fine seedbed (no clods and minimal stubble) and mechanical incorporation after application to physically move the herbicide to ‘co-locate’ herbicide with weed seeds positioned at a range of depths in the tilled zone.

• Flumioxazin also has very low soil mobility and typically works best in a no-till farming system where weed seeds are mostly on the soil surface. Where weed seeds may also be at depth (following prior cultivation) and flumioxazin is applied PSPE, tank mixing with a more mobile pre-emergent herbicide may be beneficial.

• Imazethapyr, flumetsulam, metribuzin, acifluorfen and s-metolachlor are relatively soil mobile and would be expected to reach deeper germinating weeds, assuming adequate soil moisture (rainfall) post-application.

Herbicide labels provide advice of what can be expected with regard to crop safety and how to minimise risk. There is some level of risk of crop injury from all residual herbicides should the germinating crop seed come into direct contact with high rates of herbicide. As a general rule of thumb, the following increases the risk of crop injury:

• light textured or gravelly soils

• waterlogging or heavy rainfall during emergence

• reduced seedling vigour (cool soil temperatures, insect or disease pressure, poor seed vigour)

• the herbicide has higher mobility

• higher application rates are applied.

Residual herbicides may have long soil persistence under certain situations and use rates. Be aware of rotational crop constraints. Additionally, understand the residual herbicide program used in the preceding crop or fallow and ensure that plant back periods have been met before sowing soybeans. Be particularly aware of residual herbicides used in sugarcane systems, as some herbicides have long plant back periods (over 1 year) to soybean. For example, the amicarbazone (Amitron®) label says, ‘DO NOT use Amitron® 700WG 24 months prior to planting any crop other than sugarcane’. While the atrazine label requires a plant back period of 18 months following high-rate application in crops such as maize, sugarcane or fallow.

Post-emergent herbicides

All post-emergent herbicide options used in soybean work best when applied to very small weeds, that are not stressed (e.g. waterlogging, drought) and when excellent spray coverage is achieved. In addition to providing greatest efficacy, targeting weeds when they are very small also provides control before the weeds have started to compete with the crop and adversely impacted on yield. In coastal farming systems, suitable environmental conditions for spraying at the ideal weed growth stage can sometimes be hard to meet, due to wet paddock conditions, forecast rainfall or excessive winds.

Additionally, most soybean post-emergent herbicides require excellent weed coverage. Where the weed burden is high, shading from neighbour weeds can reduce herbicide performance. 

For these reasons it is generally not recommended to rely solely on post-emergent herbicides for weed control in soybean. 

A preferred system is to have a pre-emergent herbicide program in place for the main weeds expected in the paddock and utilise post-emergent herbicides if necessary to control any escapes. Having an effective pre-emergent herbicide in place to control key weed species in the weeks before canopy closure protects crop yield and mitigates risk if conditions are not favourable for timely application of in-crop post-emergent herbicides.

Imazethapyr (Spinnaker®), imazamox (Raptor®) and halosulfuron-methyl (Sempra®) in particular have very long plant back periods for several following crops – read the label.

Grass weed control

• Several Group 1 selective herbicides are available for post-emergent control of grasses in soybean crops.

• Group 1 herbicides are all at high risk of selection for herbicide resistance. Use sparingly and only as needed. When used, ensure robust results are achieved.

• Early application is far more effective than on more advanced growth stages. Ensure very good spray coverage. Ideally target 3-leaf to early-tillering grasses that are actively growing and not stressed for optimal results.

• Always use the recommended adjuvant as per the label. 

• Group 1 herbicides are slow to translocate and develop herbicide symptoms. It may take several weeks for final control to be achieved.

• Generally, it is not advisable to tank-mix broadleaf herbicides (follow label directions where supported). Broadleaf herbicides often dramatically reduce the performance on Group 1 herbicides on grass weeds, while the preferred adjuvant for Group 1 herbicides may increase crop injury from the broadleaf herbicide. Ideally split applications by at least 10 days where possible, applying the most important post-emergent herbicide first. 

• Beware of spray drift and keep a spray diary, noting wind speed and direction. Group 1 herbicides are damaging to other grass crops (e.g. maize, sugarcane, winter cereals) and grass pastures. 

• Some Group 1 herbicides have long withholding periods to rotational grass crops, should the soybean crop fail, and replanting is required.

• Group 2 herbicides imazethapyr (e.g. Spinnaker®) and imazamox (e.g. Raptor®) have some activity on selected grass weeds. Refer to product labels for more information.

Broadleaf weed control

• There are limited post-emergent broadleaf herbicide options for soybean and most have a very small application window, requiring application to weeds generally at the 2–4 leaf growth stage.

• There are no reliable ‘salvage’ options for large broadleaf weeds or vines. Ensure paddock selection allows for broadleaf weeds to be controlled at, or prior to planting.

• Controlling leguminous weeds such as phasey bean or sesbania pea in soybean is extremely difficult. 

• Acifluorfen (e.g. Blazer®) can provide some control of sesbania pea, but excellent coverage is required, and weeds need to be very small. 

• Transitory crop damage is often encountered after broadleaf herbicide application (especially with acifluorfen). Always follow label advice regarding crop size, growing and climatic conditions at application and choice of adjuvant. 

• As a general rule, the addition of a spray oil or ammonium sulphate will increase weed control, however, also increase the risk of crop injury. Only add these adjuvants where it is specifically supported on the product label.

• The risk of crop injury from acifluorfen (e.g. Blazer®) or bentazone (e.g. Basagran®) is highest when applied under hot and low humidity conditions.

Section 6 provides additional information on weeds controlled.

Sulfonylurea tolerant soybean varieties

HB1 soybean varieties (e.g. New Bunya HB1*, Mossman HB1*, Kuranda HB1*) have been selectively bred by the Australian Soybean Breeding program and are the first generation of new varieties to have tolerance to sulfonylurea herbicides. An APVMA minor use permit (PER88483 expired 31 March 2023) was in place that allows the broadleaf herbicide halosulfuron–methyl (Sempra®) to be applied to these varieties early post-emergent for control of nutgrass. 

Further varietal development is underway to confer even greater tolerance to this herbicide mode of action, along with development of additional herbicide use patterns. 

DO NOT apply halosulfuron-methyl (Sempra®) to other soybean varieties not containing the HB1 trait, as complete plant death is likely. 

For more information on HB1 varieties and the use of halosulfuron-methyl (e.g. Sempra®).   

5.4 Non-chemical, mechanical and organic weed control options

In both conventional and organic agriculture, the objective should be to reduce the weed seedbank as low as possible over time (by preventing seed set) and ensuring all weeds are controlled in the fallow prior to planting. Ensuring a weed-free fallow at planting reduces reliance on in-crop weed control methods such as inter-row cultivation and hand weeding. 

Mechanical weeding approaches such as ‘scuffling’ (a shallow cultivation of the interrow) are commonly used in both organic and conventional cropping systems. 

Typically in organic soybean crops, weed control prior to planting is likely to require cultivation, mulching, and other non-herbicidal control methods such as flaming or steaming. 

Cultural tactics such as the use of a longer weed-free fallow period where no seed set is permitted, would reduce the weed seedbank and further reduce reliance on in-crop weed management practices. Increasing crop competition, by reducing row spacing can also assist in minimising weed growth, however, this cannot be relied on as a sole control measure.

There is no comprehensive ‘recipe’ for weed control in organic soybean crops. Organic farming systems do not permit the use of synthetic herbicides so non-herbicidal weed control systems must be developed to suit the particular weed spectrum, cropping rotation sequence and farming system.

When budgeting for organic crops, don’t overlook the cost of hand weeding, an essential ingredient not only for the current crop but also for the success of future crops in the system. In addition to the use of inter-row cultivation to control weeds, organic soybean growers will often need to employ a team of chippers to remove weeds in the plant row.

Alternative non-chemical weed controls such as flaming and steam treatments may become available, including the potential for application via the use of drones. More futuristic processes such as killing weeds by electrocution and lasers are still in the developmental phase. 

5.5 Harvest-aids and desiccating the crop

Herbicides are commonly applied to soybean and other pulse crops as harvest aids to ensure that a uniform, dry and predominately leaf-free crop is presented to the header. Herbicides are also used to desiccate green weeds, which are likely to cause harvesting difficulties. The presence of green weeds at harvest increases the chance of mechanical blockages in the header, grain quality downgrading from contamination by declared weed seeds and from staining of the harvested grain by the weed sap. Desiccants are also applied for crops that display uneven maturity.

The options available to growers are:

• Diquat (e.g. Reglone®) which should be applied when 80% of pods are yellow/brown and seeds are ripe, yellow and pliable. Diquat is a fast-acting herbicide which will cause rapid leaf desiccation and allow harvest to commence soon after application, however a 4-day harvest withholding period applies when used in soybean.

• Glyphosate (e.g. Roundup®) should be applied only after seed pods have lost all green coloration and 80–90% of leaves have dropped. Do not apply to crops grown for seed or sprouting. A 7-day harvest withholding period is required, however, glyphosate will generally take longer than that to adequately desiccate the crop.

• Saflufenacil (e.g. Sharpen®) provides rapid desiccation. Apply at crop maturity at least 7 days before harvest to mature crops when pods are yellow/brown and 85–90% of leaves have fallen, Early applications may result in grain yield penalties. Good coverage is required, with a minimum spray volume of 100 L/ha recommended. Always use 1% v/v Hasten® spray adjuvant or a high-quality methylated seed oil (MSO).

6. Herbicides registered for weed control in soybean 

The following tables (Table 4 and 5) summarise weeds controlled by post-emergent and residual herbicides. Botanical names for common weeds are listed in Table 6. 

FOR SPECIFIC RATES AND INFORMATION – ALWAYS REFER TO THE LABEL INSTRUCTIONS PROVIDED BY SUPPLIER

Ensure you investigate all chemicals before use as some have significant plant back periods for other crops that you may be using in rotation.

7. Common weeds of soybean and their botanical names

The GRDC's Common weeds of grain cropping Ute guide and Weeds in coastal grain farming systems factsheet are useful weed identification resources.

8. Further reading links and references

Congreve, M. and Cameron, J. (eds). (2019). Soil Behaviour of Pre-emergent Herbicides in Australian Farming Systems – a reference for advisers (2nd Edition). GRDC publication. https://grdc.com.au/resources-and-publications/all-publications/publications/2018/soil-behaviour-of-pre-emergent-herbicides 

Congreve, M. and Cameron, J. (eds). (2020). Understanding post emergent herbicide weed control in Australian farming systems – a national reference manual for agronomic advisers (2nd edition). GRDC publication. https://grdc.com.au/resources-and-publications/all-publications/publications/2018/understanding-post-emergent-herbicide-weed-control-in-australian-farming-systems 

Rasool G., et.al. (2017) Row spacing is more important than seeding rate for increasing Rhodes grass (Chloris gayana) control and grain yield in soybean (Glycine max), Crop & Pasture Science, 2017, 68, 620–624. https://www.publish.csiro.au/cp/CP17229 

Tepper G., (2022) Weather essentials for pesticide application. GRDC publication. https://grdc.com.au/resources-and-publications/all-publications/publications/2022/weather-essentials-for-pesticide-application 

Walker R., et al. (2020) Nutgrass control using Sempra in herbicide tolerant soybean varieties. Soy Australia, Australia. http://www.australianoilseeds.com/__data/assets/pdf_file/0016/18133/SoyAus-factsheets-Sempra-WEB.pdf 

Widderick M. (ED). (2020) Integrated weed management of feathertop Rhodes grass, second edition, 2020 update. GRDC publication. https://grdc.com.au/resources-and-publications/all-publications/publications/2020/integrated-weed-management-of-feathertop-rhodes-grass 

WeedSmart website https://www.weedsmart.org.au 

Independent Consultants Australia Network (ICAN) website https://www.icanrural.com.au 

APVMA PUBCRIS website (online searchable website of herbicide labels and permits) https://apvma.gov.au/node/10831