The abundant availability of food is extremely essential for human existence on this planet, thus making agriculture a mandatory practice throughout the world. Within two decades, a severe complication of food will arise. Hence, the advancement and progress of agriculture is essential. With the help of trending technologies like IoT, the environmental factors that affect the crops are easily monitored, and decisions are taken based on them so that crop monitoring is done remotely, which is a magnificent IoT application. Today, agriculture in the world is partially automated, and farmers mostly rely on traditional methods because of which they suffer from scarcity of rainfall and dearth of water. A plethora of techniques exist that provide automation of agricultural activities and hence increase their efficiency so that better crop output is obtained. The automation of agriculture enables reduction in human involvement. The main purpose of this review paper is to present an overview of various techniques adopted in automated agriculture systems which save the farmers' time, money and power. This paper also extracts key features of existing automated agriculture systems based on their advantages and disadvantages. This paper will assist in the development of a system which will overcome the drawbacks of existing automated agriculture systems. © 2019 IEEE.