Gardening

I have never done gardening in my whole life, but now I feel that this is something that I should try and get a little bit of experience in. It might come in handy one day. Since I know nothing I have a lot of questions.

Inclination

How easy is it to do some home farming/gardening on a plot that has up to 30 degree inclination? In order to grow veggies is it necessary to plow once a year? A friend of mine has a backyard of 4x8 meters and used a tiny plow (a bit bigger than a lawn mower). This kind of equipment can be used on terrain that has 30 degree inclination?

First I learned that instead of a lot of gardening it might be easier to consider planting trees that produce food (nuts, fruits, etc.). They need less maintenance.

Second I learned that plowing might not be needed or actually be bad. According to a book, not only is it not necessary to plow every year, it is not conducive to good gardening. The earth has natural layers which are not good to mix up. Each layer has it's own ecosystem and it's own role in the growing of plants, for example fungus occupies one layer, mostly in the form of filaments, and serves an important role in the transport of nutrients. Plowing destroys all the filaments and the transport is interrupted until they grow back. What's important is to have a good layer of mulching. Some (organic) gardeners recommend covering the ground with black plastic (several months) to prepare it for planting.

Size of plot

What is the size of land needed for veggies (sq meters)? How big a garden does one need?

Well, it all depends. Where, sunshine, rain, inclination, type of soil all matter. An expert can supply up to 10 people with a single hectare. But I believe that that needs 10 years to get the soil to be right, the trees to grow, etc. Initially it will be impossible to achieve such a return. Especially since I am not an expert. For me initially maybe food for 0.5 person/ha is realistic.

What to plant

What are the best vegetables or fruits to plant for a beginner? What is most suitable? Little maintenance, no expertise necessary, high calorie return?

I have not investigated that yet. Does anyone have an opinion?