Taking advantage of difficulties. Variable rate application based on canopy maps to achieve a sustainable crop

Aim: The aim of this work was to evaluate the use of Variable Rate Application technologies based on prescription maps in commercial vineyards with large intra-parcel variability to achieve a more sustainable distribution of Plant Protection Products (PPP).

Methods and Results: Eight vineyard plots on three Spanish wineries (Jean Leon, Viñas del Vero and Martín Códax) were selected. In all of these plots, a Variable Rate Application (VRA) system was implemented during the whole season. A UAV flew over plots at three different crop stages (BBCH 60, 75 and 81) in order to generate the corresponding canopy maps. For this process, a multispectral camera with five spectral bands (Red, Green, Blue, NIR and RedEdge) was embedded on the UAV. In order to obtain a vigor map, the NDVI vegetative index was calculated and aggregated at three different levels (low, medium and high vigor). The three different vigor zones were validated by manual measurements of canopy height and canopy width in the three defined zones. Generated canopy maps were transformed into application prescription maps using the DSS DOSAVIÑA®. Prescription maps were uploaded into the VRA sprayer that works as follows: 1) determining its GPS position on the plot, 2) getting the objective volume rate from the prescription map considering the GPS position, 3) reading the actual spraying pressure, 4) readjusting the spraying pressure to the objective volume rate 5) recording, every second, actual data about forward speed, pressure, volume rate and prescribing a volume rate and 6) generating an actual application map with the recorded data. The actual application maps obtained allows comparison with the VRA technology versus the conventional spray application. Preliminary data demonstrated a 20% savings both, on pesticide amount and on water volume, resulting also in a more profitable time consumption. Biological efficacy evaluation demonstrated no differences in control, only an increase in the efficiency of pesticide application and a reduction in environmental contamination risk.

Conclusions:

This work demonstrates in the success of PPP application using VRA technologies. The system was able to maintain or even increase the spray distribution quality in the whole canopy structure, reducing losses to the ground and cutting down drift by adjusting the optimal amount of liquid according the canopy characteristics. As in all cases PPP concentration was maintained following the pesticide label recommendations, the VRA system reduced the total amount of PPP per hectare. All together effective pest/disease control was maintained.

Significance and Impact of the Study: The PPP application requires accuracy, as imprecise or excessive use can lead to serious problems such as environmental pollution, traces of pesticides in food, and health issues in humans. The high degree of intra-parcel variability in the vineyard crop makes it difficult to determine a suitable solution for all areas of the plot. A more sustainable use of PPP will reduce the total amount of pesticides used, reduce the environmental contamination risk and increase food quality.