Task: “Programs for the application of agrochemicals and the sustainable use of resources, a real field experience”
By: Raúl Osorio, Director of Peulla Consulting and Services – Gonzalo Pezoa, Technical Head of MAGNA Exporters, Miguel Vial Group.
Our strategies for using agrochemicals will always depend on three factors that are closely related and the responsibility expressed in proportion to each of these is described in Figure 1 attached:
1. Choose a good agrochemical product (active ingredient and effective formulation), with sufficient support, a reasonable cost for its objective, ideally with low environmental impact and always consider its dosage range.
2. Use agrochemical products in a timely manner depending on the development stages of our crop and the susceptibility states to pests and diseases.
3. Finally, use application equipment that is always well maintained, clean and optimally calibrated to develop applications in a wide range of water volumes or “application rate.”
The challenge:
Every year, specialists in the productive management of fruit crops develop high-performance and effective agrochemical programs, always seeking efficiency in their use (fungicides, insecticides, herbicides, growth regulators, biostimulants, nutrients, among others). To do this, they compile updates to labels and their recommendations for use; they also corroborate the restrictions of the MRLs for the various active ingredients for the different destination markets.
In addition, a significant amount of time is required to verify and update new additional restrictions from some clients in countries with higher requirements or secondary standards (supermarkets). In these cases, the requirements or restrictions are for the number of active ingredients in an individual analysis, individual relative percentages of the AI concentrations detected or in the sum of these MRLs, as well as other toxicological components such as the ARfD, also as an individual relative percentage or in the sum of what was found.
Another ongoing concern is the search for compatibility of the agrochemical products used to achieve chemically and physically compatible tank mixes; in this way, less use of the machinery used in this task can be made and several objectives can be achieved in a smaller number of applications (saving energy and specialized labor).
It is also very important that applications during periods of greatest susceptibility do not generate spots or deposits on the fruit and cause a “cosmetic” defect in the fruit. This can cause serious damage to the quality of the fruit, leading to significant losses.
If we consider that the cost of foliar programs (nutrition and health) amounts to between US$ 3000 to 4000 / ha, that the cost associated with each application is US$ 25 / ha (MO – Machinery), and we have between 20 to 25 applications per season; this cost is US$ 600 / ha, additional.
In total we are using between US$ 3,600 to 4,600 / ha / season; it is undoubtedly a large annual investment and we must use it efficiently (https://smartcherry.cl/manejos-agronomicos/invitacion-al-uso-efectivo-y-eficiente-de-nuestra-inversion-programas-de-aplicaciones-de-agroquimicos-en-cerezos).
In addition to the search for efficient use of resources, there is the growing concern regarding the use of recommendations for water volumes adjusted to the size, state of development of the crops and the objective to be controlled.
All of the above must be implemented on the ground with equipment in good condition with its periodic maintenance, well calibrated annually, “checked” permanently on the ground and operated by highly qualified personnel.
A real experience of challenge and accomplishment of this task is the following:
About 12 years ago, when the requirements for secondary standards began, we realized that we could not fight against them, that they were only going in the direction of being more strict; we created new application programs to comply and what on paper appeared to be the best program that would ensure pest and disease control and comply with these new requirements, we did not achieve it or we did it halfway. That's when we realized that in the end, those who really generate this change are the operators and their direct supervisors.
The experienced Chilean operator has a peculiarity, with any tractor, with any misting machine and in any plantation framework, if he is given instructions, without having any further experience, he does it perfectly; for example, if he is told to apply 1,500 liters/hectare, at the end of the day he returns with the task completed and with the final result of 1,500 liters/hectare, the issue is how the distribution was in that orchard, he started by applying the equivalent of 2,500 liters/hectare, he saw that he was running out of water and regulated to 1,000, he realized that he would have water left over and the final part he did it with an expenditure of 1,200, he had a little left over and he made a border... final result of the orchard 1,500 liters/hectare.
In the first part, the product deposit was much higher than expected, which could have prevented us from meeting the destination MRLs. Then, we were left with a low deposit, which could have left us with fewer days of protection and insect damage. The final edging also left us with an excess of product that we had not considered.
Due to this reality, we began to work with calibrations that were as standardized as possible, but at first it was very complex since it required many nozzles of different colors and the actual application times per orchard were very long. Then, with the help and joint work with the people at Peulla, we generated changes to nozzles with more drops, which simplified things a lot, having only 2 colors and with application times per hectare of between 25 to 35 minutes.
It is possible to standardize the equipment with tractors and foggers of the same brand and model, but this can also be achieved with tractors that allow working at the same speed and with foggers with pumps that can maintain the working pressure with the types and number of nozzles required, in addition to having equivalent air equipment.
This search for standardization is very important since it allows us to have efficiency indicators since, if we know in advance that, for a certain calibration, the time to cover one hectare is 35 minutes, we must do everything possible to ensure that the time it takes to return to where the pumping ended is as short as possible and this involves the following:
-Loading stations with water available and nearby
-Try not to put applicators together in the same loading bays
-Products available and nearby
-Roads in good condition
-Tractors with oil that allows them to work full time
-If you have to modify the calibration, make it as simple as possible, changing pressure, gear or changing nozzles quickly, such as the nozzles that rotate.
-Supervisor with the ability to fix minor defects such as broken nozzles or dispensers.
All these points and others help us to make the time between when the equipment stops spraying and returns as efficient as possible, being able to generate indicators such as 1 pumping per hour, which is obtained from calibrations with known time per hectare and loading times of 25 minutes; with these 2 parameters we can manage our machinery, knowing in advance if with the available equipment we are able to finish on time or if we should change strategy.
This is how an external requirement, which initially caused rejection, helped us realize that we were being very inefficient and ineffective in the applications and helped us standardize a complex process that depended on people, often with very little training.
In order to develop effective and efficient application management plans, we must have previously diagnosed equipment in all its components, repaired and replaced its critical elements, perform annual and periodic maintenance, permanent cleaning and have highly trained personnel to develop the applications that will translate into the success of our crop at harvest with the least impact on the environment and people.
