Spot spraying, a technique spotlighted by Future Farming, is revolutionizing the way farmers manage pests and weeds. But what exactly is spot spraying, and how does it stack up against traditional full-field spraying methods? Future Farming delved into these questions, consulting experts from Agrifac, BBLeap, Rometron, Homburg Holland, and ABdrone to provide a comprehensive overview.
Spot spraying is a precision agriculture technique that involves the site-specific application of pesticides to small, targeted areas. Imagine a spotlight illuminating a specific area; similarly, a spot sprayer applies treatment to a designated spot on a crop or the ground. This method contrasts with variable rate application (VRA), which adjusts the dosage but still covers broader areas. Spot spraying can be executed using standard spray nozzles or more advanced pulsed (PWM) nozzles.
The size of the spot treated by spot spraying varies significantly depending on the equipment used. For instance, the Ecorobotix ARA spot sprayer has a nozzle spacing of 4 cm, while the Rumex spot sprayer RXF 600 has a spacing of 6.6 cm. Field sprayers, on the other hand, typically use nozzle spacings of 25 or 50 cm, though other configurations are possible. The height of the spray boom and the spray angle of the nozzles further determine the spot size, which usually ranges from 10 cm for specialized spot sprayers to up to 100 cm for traditional field sprayers. Experts anticipate that advancements in technology could reduce the spot size to as little as 1 to 4 cm, ensuring comprehensive coverage of weeds and volunteer plants.
One of the key advantages of spot spraying is its adaptability. Agrifac, for example, prefers a nozzle spacing of 25 cm for its efficiency and reduced chemical usage. This spacing is generally more beneficial, offering quicker returns on investment. Data for spot spraying can come from various sources, including satellite images, drones, and crop sensors. While prior data on weed hotspots can be useful, real-time systems equipped with cameras or sensors often eliminate the need for extensive pre-mapping.
Spot spraying is particularly effective in specific scenarios. In grasslands, it works best for persistent root weeds like sorrels, thistles, and couch grass. In crops such as sugar beets and onions, it excels at controlling volunteer potato plants, minimizing crop stress and enhancing yields. However, spot spraying is less effective in situations with high weed pressure, low-cost pesticides, or when battling fungal diseases like Phytophthora. In such cases, full-field spraying or VRA might be more appropriate.
The effectiveness of spot spraying compared to full-field spraying is impressive. Companies like Agrifac and BBLeap report that spot spraying can achieve up to 95% of the effectiveness of full-field spraying. The accuracy of weed detection largely depends on the type of camera or sensor used, the driving speed, and environmental factors like light and shadow. BBLeap claims a 99% weed detection rate with its spray boom cameras, while Agrifac can identify weeds as small as 5 millimeters.
Determining the amount of tank mix required for spot spraying can be challenging. Estimates are often based on weed coverage, and practical solutions like alternating between spot spraying and full-field spraying can help manage leftover liquid. Chemical injection systems offer another workaround, ensuring precise application without waste.
The data generated from spot spraying, known as “as-applied” maps, provide valuable insights into weed pressure, crop vigor, and chemical usage. These maps can inform future farming decisions, optimizing both yield and resource use.
While current regulations for spot spraying are similar to those for full-field spraying, future legislation may mandate spot spraying for specific applications. This shift could further drive the adoption of this efficient and environmentally friendly technique.
Financial viability depends on various factors, including crop type, weed pressure, and the effectiveness of the spot sprayer. Reduced chemical use and minimized crop stress can lead to significant savings and quicker returns on investment, making spot spraying an attractive option for modern farmers.