# APTM: A Model for Pervasive Traceability of Agrochemicals
## 6 Conclusions  
This article proposed a model that can monitor the use of agrochemical products and the disposal of empty packages. We have combined technology such as IoT, machine learning, two blockchains, and gamification to accomplish this. To the best of our knowledge, we have not found a model with such a combination. This paper featured related works discussing alternatives. The proposed solution is flexible since other sensors can be added to tier 1 easily. It is scalable, divided into tiers that can be updated independently without affecting the others. As future works, we indicate: (a) In future evaluations, IOTA Tangle may be used as an alternative for comparison with the combination of Ethereum and IoT. The private internal network may be changed from Ethereum blockchain to IOTA Tangle; (b) the development of public interconnection standards between multiple blockchains and ERPs to become auditable by an independent entity; (c) The future generation of cryptocurrencies by the farm blockchain nodes may have ballast with proof of points generated by gamification and subsidize future exchanges for carbon credits; (d) RFID tests on large monoculture plots (soybeans, corn, and cotton) creating virtual fences inside the farm borders; (e) Future implementations to evaluate the model's energy consumption, operating costs, including installation, maintenance, and monthly internet costs for the farmer; (f) The arrival of 5G in rural areas could be explored during future applications of the model. (g) An expansion of the questionnaire should be carried out after better post-Covid-19 pandemic conditions allow, including more farmers of other monoculture cultivars. (h) A battery of statistical tests on data communication within the model and its processing time. The novelties features in APTM are:  
* Scalability: This model allows the expansion and exchange of sensors at any time, including new sensors with other functionality. * Expandability: Sensors can be installed at multiple data collection points, virtual machines can be cloned, and more blockchain nodes can be added to the reverse supply chain. * Auditability: Data collections at tier two can be verified from dashboards at tier 4. Blockchain transactions can also be verified via tier 4. The processing characteristics of the Ethereum blockchain ensure the secure recording of transactions. * Visibility: Adopting a services model allows future applications to connect to service ports to create new tier-four views. * Predictability: Adopting machine learning will allow for future actions in crop planning by the farmer and several other AI services that can be added to tier three. * Accessible: The choice of technologies adopted in the prototype was not proprietary, allowing implementations with the most various budget constraints to adopting the model. Finally, we conclude that the APTM model is viable and can be extended to productive farms. The model can also be adapted to treat other sensitive and costly products such as fertilizers without further modification, which proves its adaptability and flexibility. The model can also be used on a large scale as services developed in tiers 2 and 3, i.e., it can be allocated to cloud processing service providers. This model serves any farm that uses costly and highly toxic agrochemicals which need monitoring. **Author Contributions:** Conceptualization, E.S.M. and R.d.R.R. ; methodology, E.S.M., R.d.R.R., J.L.V.B. ; formal analysis, E.S.M., R.d.R.R., J.L.V.B., A.M.A. ; investigation, E.S.M. ; data curation, E.S.M., R.d.R.R., J.L.V.B., A.M.A. ; writing--original draft preparation, E.S.M. ; writing--review and editing, E.S.M., R.d.R.R., J.L.V.B., A.M.A. All authors have read and agreed to the published version of the manuscript. **Funding:** This work was partially supported by the following Brazilian agencies: FAPERGS (project funding 17/2551-0001208-9). **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Not applicable.