good question, im not an industrial farming expert, but i definitely grow a shit ton of food on my own 1 acre property, using only hand tools. One reason small scale farming is more efficient is that the areas planted do not have to adhere to dimensions that will fit industrial farm equipment. For example, think about a grape plantation on a rough hillside. its simply not possible to use industrial harvesting equipment there, so it must be done by hand, yet still produces massive amounts of nutrition/calories off rough land. This applies to individual/family plots too–they aren’t all just flat farmland, they are on hillsides, uneven terrain, etc. An example would be in the third world like in south africa, there are vast neighborhoods of small two-room family shacks, with a bit of land to the side. Each family there produces an unexpectedly large amount of corn, sugar-cane, root veggies, etc on very tiny plots. No industrial equipment could ever fit there or farm there. They produce a large amt of food right next to their shack, and virtually everyone does it because its cheaper and more efficient than walking (yes, walking, they don’t own cars) to the store a few miles away. And another reason, kind of hard to explain, but individual people doing individual farming on their own land tend to take better care of their plants. Pests have a much more difficult time in situations like this, because where they really thrive are gigantic fields of monoculture crops. for example, corn. An industrial corn field often allows weeds and pests to take over the undergrowth around the corn, which significantly limits crop returns, but there are just so many damn corn stalks that can be harvested industrially, that it doesnt’ matter and the end result is still a huge amount. But in relative terms, growing your own corn next to your own house, and paying more individual attention to each plant, results in better actual yields.
Industrial farming relies on complex equipment, and the fact that there is just so much flat land available, that they don’t “need” to be efficient. Take a look at how much diesel is used on industrial farms, and it kind of shows the point. It’s a lot. In general, human bodies doing manual labor are extremely efficient compared to other forms of work, provided they have the knowledge and appropriate context. It takes 3-4 miles of walking to burn off the calories in two slices of bread. Humans are very efficient when working with their hands.
I mean, you’re right. We can grow a shit ton of potatoes on flat land with modern methods. And we do. But that absolutely does not mean individual/small scale urban farming couldn’t do just as well. This year I grew 8 roma tomato plants in a 4ft by 10ft garden. They provided enough tomatoes (400-500) to make over 50 jars of tomato sauce, enough to supply our household for a year. I don’t live on flat or even fertile farm land. My terrain is rocky sandstone, uneven. No mechanized farming could ever be done here. Yes I had to work and amend the soil. Yes it’s hard work for several days of the year. But I need exercise anyway. I don’t buy a gym membership because of the garden work I do. The seeds and plants were free because I save seeds. The total cost of the tomatoes was just my own labor, the water (around $10 worth), and misc costs. The sauce is far cheaper than anything I could buy at the store, since I supplied all of the raw material.
The point is, anyone with even a small plot of land is able to grow large amounts of food, probably a lot more than they think. And most of those places are places that without small-scale/individual gardening, would never see any food production. The issue is, it takes time, knowledge, and special care, and many people aren’t able to pull that off. I realize that, and it’s fine. That’s why big farms exist. But the truth is that there are a large number of people out there who have the time, and ability to do it, but they just don’t know how, or even believe it’s possible. Even just one apple tree can provide a huge amount of nutrition and calories if well cared for and placed correctly.
Wheat and rice? Yea, those don’t lend themselves well to small scale farming. For those things, you are absolutely correct. However, don’t assume those things are necessary. It’s just carbs. I have beets growing in my back yard (enough to last an entire year) that contain more carbs, and more importantly, vastly more nutrients, than a much larger field of wheat or rice. Don’t get me wrong, I love me some pizza and bread, and I buy lots of wheat flour from local farms around me. But those types of crops are NOT necessary for people to eat. They’re luxuries. The proof? Africa and other arid zones. People subsist on small scale farming (and foraging) of root vegetables (casava is the most well known), not vast plantations of rice and wheat. and they do just fine. Root vegetables are often a lot more nutritious than grass seed (which is what rice and wheat are). You just can’t make pizza out of it due to no gluten :(