What role does agriculture play in the book of Genesis?
Many of the people depicted in Genesis are farmers and sheepherders, from the very beginning. Adam and Eve lived in a garden, after all.
When Adam and Eve were evicted from the garden, they had two sons, Cain and Abel, who were involved in agriculture. We see this from the offerings they made to God. Cain offered grain and Abel offered up one of his animals.
Later on, Abram and Lot had to part ways because the land they were living on was not sufficient to support the herds each man had. Animal sacrifice was hugely important in the entire Old Testament, beginning with Abel. In order to be able to support a large family and to be able to offer appropriate sacrifices to God, people needed large herds.
There are more incidents with the size of herds, such as when Laban tricked Jacob into marrying his older daughter, Leah. Jacob had to wait another seven years for Rachel and he ended up taking a large part of Laban's flock because he tricked Laban.
The story of Joseph and the Coat of Many Colors also ends up being about agriculture. Joseph is rescued from prison because the Pharaoh has a dream that ends up being about an upcoming famine. Joseph suggests storing up grain during the seven good years that were to take place so that they would have food for the seven bad years.
The agricultural life is one of uncertainty. Farmers are never sure what will happen next, whether it is too much rain or not enough. Animals can prosper or they can get sick and die. It is probable that the unpredictability of agricultural conditions contributed to people's desires to know God. Agriculture created both the desire and the means, through sacrifice, for worshiping God.