Variable Rate fungicide application is a well-known approach in precision agriculture that adjusts the amount of fungicide applied based on the current conditions of the crop and field. Unlike traditional single-rate fungicide application, VR fungicide optimizes fungicide usage, reduces environmental impact, and improves the economics of crop production. This technology utilizes the most recent satellite imagery of the current crop. Typically, images that are 2-3 days old work best for VR fungicide. These images reflect recent changes in crop stand that impact the necessity of full-rate fungicide application across the field. To achieve the best resultst is always advisable for the grower or agronomist to do ground-truthing by visually checking the accuracy of the map and crop stand quality in the best and poorest areas.
Before deciding to choose VR Fungicide Application, growers need to consider the benefits of this technology.
Reduction in Fungicide Usage: variable rate fungicide application can significantly reduce the amount of fungicide needed by targeting specific areas that require treatment. Studies have shown fungicide reductions of up to 22.24% at early stages and up to 25.93% at later stages compared to single-rate application, leading to considerable cost savings.
Improved Disease Control: By tailoring fungicide applications to the specific needs of the crop, VR fungicide application can maintain or even improve disease control without increasing chemical usage.
Lower Environmental Footprint: Reducing the amount of fungicide applied helps lower the environmental footprint of agricultural practices. This reduction minimizes the risk of chemical runoff into water sources and decreases the overall chemical load in the ecosystem.
Increased Profitability: The combination of cost savings on fungicides and maintained or increased yields can significantly boost farm profitability. The gross profit from combining selective harvesting and VR fungicide applications can reach up to $90 per hectare per season.
As with every piece of modern technology, this approach has an optimal timing window for the best yield response and best economics.
Early applications of fungicides, particularly at the first signs of disease or at critical growth stages, can optimize disease control and delay resistance development. Early applications are beneficial in high-disease-pressure environments to curb the spread of pathogens effectively.
Applying fungicides at specific growth stages, such as the full emergence of the flag leaf, can maximize disease control and yield benefits. Research indicates that applications at these critical stages are highly important for maintaining green leaf area and preventing yield losses due to diseases like septoria leaf spot and powdery mildew.
In some cases, using a split application approach, where fungicides are applied at multiple growth stages, can balance disease control and fungicide resistance management. For example, two-application programs in winter wheat have been shown to be effective in managing diseases while increasing the lifespan of the fungicide’s efficacy.
Variable rate application includes precision location where fungicide should be applied.
Fields with significant variability in soil quality, biomass, and disease incidence benefit the most from VR fungicide application. In such fields, areas with higher biomass and disease pressure receive more fungicide, while less affected areas receive less, optimizing resource use.
Regions prone to specific fungal diseases, such as areas with high humidity and frequent rainfall, are ideal for VR fungicide application. Precision application in these areas can effectively manage diseases while minimizing environmental impact.
Fields with significant bare spots due to environmental and other reasons can waste fungicides if treated uniformly. VR technologies that detect and adjust for bare spots can lead to substantial savings and reduce unnecessary chemical usage.
Variable Rate fungicide application offers a sustainable and economically viable solution for modern agriculture. By adjusting fungicide applications based on real-time crop and field conditions, VR fungicide application enhances disease control, reduces chemical usage, and increases profitability. For optimal results, it is essential to apply fungicides at critical growth stages and focus on heterogeneous fields and high-risk areas.