Kiara Lutz
Precision Agronomist
kiara.lutz@swatmaps.com

Kochia (Kochia scoparia) has grown to be a problematic weed in much of the semi-arid cropping areas of the US and Canada. The pressure it has on crops is most notable in saline and marginal areas, which are commonly found in SWAT zones 9 and 10. The rapid growth of this weed, its ability to tolerate high salinity, drought and heat, as well as growing herbicide resistance problems make it a massive threat to crops.

If kochia is left uncontrolled, at maturity and with wind the tumbleweed will spread seeds throughout the field. With each kochia plant producing at least 15,000 seeds, dense kochia patches with low crop competition can produce millions of seeds per square metre (Canola Council, 2023). However, with proper management, growers can reduce the soil seedbank and prevent kochia from reaching maturity. On top of that, farmers who bring precision ag tools like SWAT CAM into their operation find managing kochia to be a whole lot easier.

SWAT CAM is an autonomous imaging system designed to capture, assess, and evaluate crop establishment and weed pressure. It is a proprietary product for full farm SWAT MAP users that are clients of Croptimistic Technology or any premium SWAT MAPS service provider. Here’s how it works:

Step 1: The Capture
SWAT CAM is mounted onto sprayer booms (one SWAT CAM on each boom) which will then auto capture images of weeds and crop every 50 to70 feet each time the equipment enters the field.

Step 2: The Analysis
These photos are then processed using machine learning technology. During this step, crop and weeds are identified and various maps are generated. Crop and weed data are divided and presented separately, unlike satellite imagery where NDVI could represent both crop and weed biomass.​ This allows SWAT CAM to determine percent weed cover, percent crop cover, and specifically identify kochia. Once kochia has been identified in the field images, SWAT CAM can generate kochia models indicating the kochia coverage across the field.

Step 3: The Application
Since kochia is an early germinating annual weed, it requires an aggressive approach to spraying. Incorporating a previous kochia map into your early season spray jobs can get you off to a phenomenal start with your weed control. 

Effective control of kochia requires use of premium herbicide products which are expensive to apply at a flat rate across a field. However, SWAT CAM can dramatically reduce the costs of Kochia control by accurately targeting specific areas that are affected, providing a much stronger return on investment than flat rate applications. A custom spray requisition can be created using the kochia model to build an on/off herbicide application, spraying only where kochia has been found. SWAT based prescriptions can also be combined with the SWAT CAM kochia models to ensure all high risk areas are covered. Through this process, there can be huge savings as a of result only applying product to the areas with kochia patches compared to applying at a flat rate across all acres. After spraying, SWAT CAM imagery can also be used to check the effectiveness of the herbicide application.

It's important to note that reliance on herbicides alone should not be the only tool used to control kochia, or any other weeds. Crop competition is the most important tool for weed control, so variable rate seed is another valuable tool to use in these problem soils that often have high mortality and allow kochia to thrive with little competition. Increasing seeding rates 20 to40% can be an effective cultural control tactic, increasing crop competitiveness that helps reduce weed escapes.

Kochia maps are a great example to start with for SWAT CAM use cases, although it has much more to offer to your farm! Connect with your SWAT MAPS agronomist or consult our sales team to find out more about SWAT CAM’s variety of applications. 

Outside Source:

Canola Council. (2023, November 30). How to contain herbicide-resistant Kochia. Canola Council of Canada. https://www.canolacouncil.org/canola-watch/fundamentals/how-to-contain-herbicide-resistant-kochia/.