Build a house underground on agricultural land

That would depend entirely on where you are located, and the laws/rules that apply in your jurisdiction. But wherever you are, building an earth covered house takes some engineering skills, so suggest you ask this question of your engineer.

thank you for your speedy reply, I am not at the point yet of affording a structural engineer, only drawing plans only from my bricklaying experience but i think i have done well in my plans to hold back the earth and integrate a system that will allow filtered water to flow,

Don't forget to include the cow and cowpie live load factors, to include impact.

Mike McCann
MMC Engineering

the soil integrity?

Building an Earth Ship? Did a little work on one ~20 years ago in CO, but was not engineer of record or involved in building permits.

how did you approach it? damp is my main concern

At that particular location, damp was not an issue, and I don't think they did much. It was actually set into a little knoll that sloped away on the back and sides. It was cut into some very fractured and somewhat weathered granite-like rock that was quite pervious, so anything that did infiltrate promptly dropped well below the house, which I'm guessing was a couple hundred feet above the water table. No drains were needed. It was absolutely dry during exc. I haven't been there in several years, and can't recall whether they ever got any water in. The owner was a friend, so maybe I should call him up to say hello.

That rock was also just about perfect for stability of vertical cuts up to about 8', and being excavatable (is that a word?) without huge difficulty using a small hoe. Lucky site selection.

Generally, earth covered structures need to be waterproofed on the outside, a protection board used to protect the waterproofing, then a drainage layer with geotextile between the earth and the gravel to prevent clogging, a perforated drain pipe with geotextile sock placed at the bottom, and drain to daylight. Below ground, and depending on where you are, humidity could still be a problem, and you can handle that mechanically.

you might get some good ideas from this place. Saw a video on TV the other day. The do have water coming into the cave from time to time, especially in the winter and when it rains hard. They collect a lot of it for drinking and use french drains and trench drains and humidifiers to remove it.