  The use of Internet of Things (IoT) with the Internet of Nano Things (IoNT)
can further expand decision making systems (DMS) to improve reliability as it
provides a new spectrum of more granular level data to make decisions. However,
growing concerns such as data security, transparency and processing capability
challenge their use in real-world applications. DMS integrated with Block Chain
(BC) technology can contribute immensely to overcome such challenges. The use
of IoNT and IoT along with BC for making DMS has not yet been investigated.
This study proposes a BC-powered IoNT (BC-IoNT) system for sensing chemicals
level in the context of farm management. This is a critical application for
smart farming, which aims to improve sustainable farm practices through
controlled delivery of chemicals. BC-IoNT system includes a novel machine
learning model formed by using the Langmuir molecular binding model and the
Bayesian theory, and is used as a smart contract for sensing the level of the
chemicals. A credit model is used to quantify the traceability and credibility
of farms to determine if they are compliant with the chemical standards. The
accuracy of detecting the chemicals of the distributed BC-IoNT approach was
>90% and the centralized approach was <80%. Also, the efficiency of sensing the
level of chemicals depends on the sampling frequency and variability in
chemical level among farms.
