What a fun project. I took a look, and it got me thinking about a few things. That said, overall I think it still needs a ton of work to be very useful.

For example, the partial inclusion of livestock seems unhelpful at the moment. Apparently chickens just steal random food from humans (additional calories needed to feed them) and don't provide any eggs for humans to consume. In practice, chickens can largely just forage if given enough good land to work with, even though in the good times now people often just buy in feed for them.

If you want to include livestock inputs and outputs such as animal feed into this, that's a whole other level of complexity that's not yet remotely addressed in this tool. Livestock generally provide calories for humans, often a lot of them. They also consume massive quantities of food and require huge amounts of land and water, although, there's a long spectrum there from meat rabbits and chickens to beef cattle.

The proportional setup is also a bit backwards to me, where it would likely be more helpful to most people to see a recommendation of the split across their desired crops, or otherwise help them understand that for a given space, potatoes will provide exponentially more calories than leafy greens. The sliders could be set to a reasonable default, and then they could adjust dynamically. The current implication is that it's reasonable to set potatoes to 2% and Kale to 98% of the harvested calories.

It is misleading as a slider of "% calories from swiss chard" would correlate to massive changes in land use, etc. In practice, you simply can't crank up most veggies like that and actually farm enough of that on the land and with the time and resources available to generate the calories implied by the slider.

Overall, it's an interesting endeavor, but for it to be of much use to anyone, I think there's still a massive amount of work that'll need to go into thinking things through more and building out the features and related systems.