  The world population is anticipated to increase by close to 2 billion by 2050
causing a rapid escalation of food demand. A recent projection shows that the
world is lagging behind accomplishing the "Zero Hunger" goal, in spite of some
advancements. Socio-economic and well being fallout will affect the food
security. Vulnerable groups of people will suffer malnutrition. To cater to the
needs of the increasing population, the agricultural industry needs to be
modernized, become smart, and automated. Traditional agriculture can be remade
to efficient, sustainable, eco-friendly smart agriculture by adopting existing
technologies. In this survey paper the authors present the applications,
technological trends, available datasets, networking options, and challenges in
smart agriculture. How Agro Cyber Physical Systems are built upon the
Internet-of-Agro-Things is discussed through various application fields.
Agriculture 4.0 is also discussed as a whole. We focus on the technologies,
such as Artificial Intelligence (AI) and Machine Learning (ML) which support
the automation, along with the Distributed Ledger Technology (DLT) which
provides data integrity and security. After an in-depth study of different
architectures, we also present a smart agriculture framework which relies on
the location of data processing. We have divided open research problems of
smart agriculture as future research work in two groups - from a technological
perspective and from a networking perspective. AI, ML, the blockchain as a DLT,
and Physical Unclonable Functions (PUF) based hardware security fall under the
technology group, whereas any network related attacks, fake data injection and
similar threats fall under the network research problem group.

Computers and Society