Sep 10 2021

Backrow reliability & safety – You can count on it!

Backrow – Crucial for residual herbicide performance in suboptimal conditions

Take the performance uncertainty and safety risks out of your residual herbicide programme with Backrow’s reliability & safety – You can count on it!

Pre-emergence residual herbicides have become vital in the war against black-grass and other hard to control grassweeds such as ryegrass and brome spp. Achieving the best results is essential to minimise population growth and the threat of further weed resistance, but like most aspects of crop production, their performance is highly dependant on the weather. The addition of adjuvant Backrow pre- and peri-emergence limits weather constraints on herbicide performance and protects crop and groundwater safety, making it a crucial partner for both reliable and safe herbicide efficacy at the early weed control timing.


Backrow reliability & safety - You can count on it!

Download our Backrow Handbook


Residual herbicide performance – Requirements & issues

Uniform application to maximise coverage & minimise survivors

At the pre- and peri-emergence spray timings, the target is the soil. The performance of residual herbicides pre- and peri-emergence is heavily reliant on uniform and effective coverage across the soil surface to ensure full contact with all germinating weeds. The issue: Pre-emergence applications to bare soils are prone to drift and whilst drift reducing nozzles help reduce drift, they also reduce coverage which risks weed escaping control and the need for follow-up treatment.




Moist seedbeds for herbicide uptake

Moist seedbeds are critical to the performance of residual herbicides. Only in the presence of moisture can herbicides be absorbed into the roots and shoots of germinating weeds. For weed control success, the herbicide must also be located in the weed germination zone (the top 5cm of the soil). Typically some rain will be required to move the herbicide from the soil surface where it was applied through the soil profile. The volume of rain/soil moisture required will vary for every herbicide active ingredient. You can learn more about this in our Backrow handbook. The issue: In dry soils there may be insufficient moisture to move the herbicide and its active substance to the weed germination layer and certain herbicides may bind too tightly to soil clay and organic matter. 

Retention in the top 5cm to control germinating weeds

Pre-emergence soil-acting herbicides should migrate relatively slowly in the soil.  The surface layer of the soil (0-5cm) is particularly important as it is the zone from which weeds germinate. For weed control success, the herbicide must also be located in the top 5cm and be retained to control flushes of weeds that may germinate over time. A longer presence of the herbicide in this soil layer contributes to better uptake of the active substance by germinating weeds, which ultimately increases the effectiveness of the herbicide. The issue: Residual herbicides and their active substances can leach into the soil, particularly with heavy rainfall and light soils. They often require additional support with an effective adjuvant to keep them in the weed germination zone. 


Retention in the top 5cm for crop and groundwater safety

To be effective and safe to crops and groundwater, herbicides must bind to soil colloids (clay, organic matter) with only a small amount remaining in solution. The issue: With excessive rainfall, even herbicides with low mobility such as pendimethalin, can be lost from the weed germination zone, particularly in light soils, and be washed to the root zone of the crop where phytotoxicity can occur. This can be particularly problematic with the stacking of residual herbicides late in the autumn to control difficult grass-weeds such as black-grass, and when soils can become saturated with prolonged spells of heavy rain. Any herbicide damage to the crop will not only impact establishment, it will also reduce the crop’s competitiveness against germinating weeds that will be fighting for light, space and nutrients in the soil. Herbicides with high mobility also pose the biggest threat to groundwater where leaching may occur with excessive rainfall. 

Aim for 97% black-grass control to contain populations

97% black-grass control is easier said than done right, but it’s the magic number required each season to stop the population from growing. Even with all the cultural controls in place and working well, suboptimal herbicide performance can let you down. Early in the autumn soils may lack sufficient moisture for herbicides to work at their best. Late into the autumn and winter we’re likely to have too much rain with the risk of herbicides leaching from that top 5cm which will reduce the concentration of herbicide in the top layer and move it lower down – that’s not good for weed control or crop safety. We also have the risk of wind gusts as we head later into the autumn/winter. Or you can take the performance uncertainty and safety risks out of your residual herbicide programme with Backrow.

Backrow reliability & safety – You can count on it!

Backrow reliability & safety - You can count on it!

Backrow is a vital performance adjuvant for pre- and peri-emergence residual herbicides to work at their best. Backrow powers residual herbicides in suboptimal soil and application conditions by reducing drift and by optimising moisture and herbicide retention in the top 5cm of the soil. The resulting improvements in herbicide coverage, uptake and safety are crucial benefits to help ensure your herbicide programme is both reliable and safe for a weed free start.

Fewer survivors

Backrow reliability & safety - You can count on it!


Reduces spray drift, improves coverage

Backrow creates the perfect size spray droplets for pre- and peri-emergence herbicides to work at their best. It reduces the number of fine spray droplets smaller than 100 microns which are the most susceptible to drift, and increases the number of droplets in the optimum size range for improved deposition and optimum spray coverage of the soil. Backrow increases the number of touchpoints with germinating weeds, ensuring fewer survivors.


Improves moisture retention in top 5cm

Backrow retains moisture in the top 5cm of soil, improving the efficacy of residual herbicides in dry conditions. By “holding on” to soil moisture, a higher concentration of herbicide can be dissolved in the soil water and available for uptake into germinating weeds, rather than being bound to soil colloids. Backrow adds valuable performance in dry soils.

Improves performance in dry soils

Backrow reliability & safety - You can count on it!

Improves performance in wet soils

Backrow reliability & safety - You can count on it!


Improves herbicide retention in top 5cm

Backrow helps retain herbicides in the top 5cm of the soil, creating a barrier to emerging weeds. This can be a life line for herbicides in wet soils that otherwise can be lost, especially in light soils. A longer presence and increased concentration of herbicide in the top 5cm of the soil results in a higher uptake of herbicide into the roots of germinating weeds and leads to more effective weed control in wet soils.


Improves herbicide retention in top 5cm

Backrow improves safety by minimising herbicide movement beyond the weed germination zone to the crop seed and emerging shoots. Backrow is therefore a crucial safener for herbicides that can be lost with excessive rainfall, and is particularly valuable when used with residual stacks to protect crop safety. Backrow is a very valuable stewardship tool for mobile herbicides which can be leached to groundwater in very wet conditions.

Crucial safener to crops and groundwater

Backrow reliability & safety - You can count on it!

To understand more about the performance requirements and challenges affecting herbicide performance, and the impact of dry seedbeds and heavy rainfall on specific herbicide actives, download our Backrow Handbook here.


Backrow – Adds a mean +9% grassweed control

In replicated field trials over the last 12 years (2009 to 2021), Backrow has improved the control of various grassweeds by an average of 9% – that is the mean of 52 comparisons either pre- or peri-emergence, and with a range of residual herbicides applied in winter cereals. In suboptimal conditions, the additional grassweed control achieved with Backrow has been as high as 33%.

What is +9% fewer black-grass heads worth?

9% fewer black-grass heads
At 500 heads/m2 = 45 heads 0.45 t/ha = £72/ha


Testimonials and case studies

Read more

Summary – Why Backrow?

  • Compatible and safe with all residual herbicides
  • Valuable product stewardship tool for at risk actives
  • Proven performance in trials and on-farm
  • Valuable resistance management tool
  • Class-leading performance – the UK’s no.1 residual herbicide adjuvant (Source: dmrKynetec AgriInsight 2019/20)
  • Reliable and safe weed control in suboptimal conditions

Backrow product information 

Classification: Adjuvant

Composition: Emulsifiable concentrate containing refined petroleum oil

Recommended use: With all approved pre- and peri-emergence residual herbicides

Soil type: For use in all soil types except pure sand

Rates of use: 0.2 L/Ha in Autumn, 0.4 L/Ha in Spring

Mixing: Add to the spray tank first before adding crop protection products

Pack size: 3 litres


Download our Backrow Handbook


Our Backrow Handbook is packed pull of information to give you a greater understanding of the constraints on herbicide performance and why Backrow is a valuable partner in suboptimal conditions. We’ve also included trials results, FAQs and access to our Backrow Tutorial.

Alternatively, please get in touch with Stuart below – he’ll be more than happy to assist with any questions you may have.

Get in touch

Require technical assistance or product information? Please get in touch with our Technical Manager, Stuart Sutherland.

For all other general enquiries, please email or call us at the office. If you’d prefer, drop us a message using our contact form and we’ll get back to you as soon as possible.

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