I am thinking that while it may have been important to Ueshiba in his time and social context that it is probably not very relevant to most of us in our current time and context. In this day and age I can't imagine too many aikidoka participating in farming just because it was important to Ueshiba in his day.
I believe that connecting with living things is important in any age. I think that the disconnect that we often experience in modern society (fast paced life with technology being a blessing/curse) is a major problem and contributes to apathy towards our fellow man and the world around us in my opinion.
Further, that sense of connection with other living beings (in Aikido practice-- people) is cited as one of the reasons to train. In my case this is coming from someone who cites self-defence and practical Aikido as pillars. While I completely agree that "farming" is not realistic for most of us, the lessons from doing such work could be gleaned from caring for plants, landscaping on your yard, or in many other ways.
It seems intuitive that if one one desires to be in harmony with nature there needs to be some connection to it. It seems that aspiring to protect livings things--beginning with ourselves and then if possible our attacker/s is a central tenant of Aikido so to have a connection with nature and the beings within it seems to logically follow. If not, then maybe we should all be doing Systema and skip the connection stuff as well as ethical aspirations.