I guess that I wasn't clear
I assumed that shtf meant a breakdown in society.
Farming. I do remember agriculture in the south some 60 years ago and I am the managing member of a family farm llc.
If shtf, there won't be wide scale farming - probably a reversion to subsistence farming if people have skills. Most don't. I can tell you that you don't want to go back to the dirt floor, bathroomless shacks that I saw growing up. In fact I remember in-door plumbing coming in the 1960s to relatives with whom I was staying. People sure get slowed down when bathing is standing in a large pan and pouring cold water over yourself!
There is probably underlying assumption that a person would get ahold of a mule, a plow, and seed. Ok. Try finding a mule, plow, various seeds in bulk or a horse drawn wagon in your area.
My great grandfather had a hernia develop during the civil war. There weren't surgeries in the 19th century - so he wore a truss for the rest of his life. Most farmers ended up disabled by torn rotator cuffs. I have personally had both shoulders done by modern medicine and a number of other surgeries. So, if shtf and you go to subsidence farming, I doubt that you will find modern medical care.
So for most, the reality is dragging a stick in the ground to plant seeds, trying to find water, doing without fertilizer, doing without a work animal.
In today's society, speak to an older person. They try to locate near doctors, medical centers. A lot of young people think that they will retire to the country when they retire - and then the reality hits them. Even modern farming (home farming) is tough. There are mighty few people who have a family garden that supplies them with all the fruit and vegetables.
Understand, if you want to believe that you already have the skills of a 19th Century American Indian or farmer and will survive in 2013 US after shtf, go right ahead. I have a lot of those skills and doubt that I would with the population density of today.