> So we should focus on long-term sustainable farming.

You cannot farm soil for longer than 8-10 years without major nitrogen, and phosphorus replenishment. Actually lived in the sticks, and did farm labour in my childhood.

Controllable soils which are good at intaking, and retaining fertilizers are sustainable.

Bad soils with unusual soil chemistries can get depleted no matter how much fertiliser is dumped. That's true.

I don't know if you've come across this video on HN before, but I discovered it here and it was an eye-opener for me. It's a guy called Gabe Brown who transformed his farm into one that needed no fertilizer by using no-till and rotation. One of the most compelling things is that he's no tree-hugger (he even has an uncomplimentary comparison with the soil from an organic farm) - his focus is squarely on profit, which goes up when you're not forking out huge amounts of money on chemicals. I thought I'd give it five minutes, then 2.5 hours later I realised I'd watched the whole thing.

https://www.youtube.com/watch?v=uUmIdq0D6-A

There's a podcast called "How To Save A Planet" that did an episode on this that I found rather enlightening:

https://gimletmedia.com/shows/howtosaveaplanet/76hmbge/soil-...

They focus on two farmers, one a small-scale farmer in NY who started with the vision of a sustainable farm, and a commodity farmer in Minnesota who was looking for ways to improve yield. The Minnesota couple are, like your example, not at all "tree-huggers;" they're just people who want to survive. And what they found is that they can get more crops, for less money, while also limiting their exposure to potentially harmful fertilizers and pesticides.

They see a lot of resistance from their neighbors, because conventional farm knowledge is so ingrained in their culture. Running a farm is tricky, and experimenting can be the difference between profit and losing your shirt. There's just not much will to risk losing the land that's been in a family for generations on a quest to find a better way.

I saw this on Netflix Kiss the Ground.

Feel like I'm missing something. State universities all over the nation have agricultural programs. Are they teaching stuff like cover crops? In other words, does this guy align with the conventional experts, or is he fringe, or does the industry have a schism?

He started as fringe out of necessity. He and a few others are now the leaders of a paradigm shift. Gabe Brown has shown that it is immensely profitable to ditch costly chemical inputs and manage a farm as an ecosystem. He wasn't the first to return to farming this way. But, he has done a lot to spread it around.

Ag extensions mostly recommend the high input farming methods. What Gabe Brown practices is more than just cover crops.

It's absolutely true that you can't keep farming the same soil year in and year out and expect it to produce. This is why crop rotation is done and why fields are allowed to remain fallow from time to time. It seems to me that these concepts are bundled in the term "long-term sustainable farming."

Source: grew up in the sticks and worked on the family farm as a kid.

> is why crop rotation is done and why fields are allowed to remain fallow from time to time.

Natural nitrogen replenishment rate is microscopic. And it will do absolutely nothing about phosphate depletion.

Crop rotation implies the selection and plating of nitrogen fixing crops. For example, because corn requires significant nitrogen, we would plan peas alongside corn. Peas are nitrogen fixing and the corn stalks provide a good structure for the vines. The next season, the corn field would be planted with something entirely different.

Phosphate replenishment can be done by spreading manure or using fertilizers. It's a harder problem, but you have to work the problem.

> Crop rotation implies the selection and plating of nitrogen fixing crops.

Yes, and and the rate of replenishment, even if you dump many times more soy straw on the fields than you will harvest, will still be microscopic.

It plainly doesn't work for anybody, but people who only farm for themselves. It's a grandly inefficient use of a scarce resource — land.

Even if the soil will be squirming with nitrogen fixing organisms, and nothing else for many years, it's nitrogen intake will be like a single nitrate application, or less.

> Phosphate replenishment can be done by spreading manure

And catch god knows how much food borne diseases in the process. That's disgusting, and absurd in the 21st century.

What farmers did when I was growing up was they divide their lot into 4. Farm on three - put compost on other and rotate yearly.

but that cuts your yield by 25%.

Wouldn't a competing farm be more profitable to add fertilizers to the soil to replenish the loss nutrients, which means they can price out the crop rotation farm?

In most of western world agriculture is subsidized: that 25% of farm land that's on a break will be paid by the government. The gov mandates and pays also for crop rotation.

Profit includes changes to asset value; it's not in the farmer's interest to destroy his soil.

In the short term such a farm would indeed be more profitable, but in the long term? The "less profitable" farm would close shop and be replaced by a fertilizer farm... and then, as a net result, society is worse off.

This is why regulations (and to combat their evasion by other countries, anti-dumping tariffs) are needed.

You would see a 25% cut in revenue (yielded crops to market) but also would see a cut in your costs (you aren't tilling, planting seeds, harvesting, putting wear and tear on tools, transporting to market) that would offset it.

The economies of scale of industrializing farming means that cutting the planting and harvesting by 25% doesn't cut the cost by the same 25% (i.e., the same economies of scale works against you when you try to decrease your scale!).

I did not mean to imply that costs would drop by exactly 25%, just that you might not see the hit to your profit margin you would expect due to your costs also decreasing with decreasing revenue.

It doesn't, because you will get no yield if you don't let a field go fallow once in a while

What makes “good” soil? Is it a particular animal? Location? Rainfall? Nearby vegetation?

Can you buy good soil or is it part of the land and just too deep/not worth buying?

It is a combination of factors, but the primary determinants are the mineral composition and the organic and biological content. It's more cost effective, though time consuming, to make soil in place than it is to strip mine it and transport it.

https://www.nature.com/scitable/knowledge/library/what-are-s...

You can always import good soil sure. Go to a rich land place and dig it up. But it will slowly wash away in the rain.

Good soil needs lots of dead plant stuff. Bad soil is clay or rocks.

True, but presumably there exist (possibly not-yet-invented) high-yield farming practices which fix atmospheric nitrogen without the need for fertilizer. There’s just not been any economic pressure to use or invent such a practice, since presumably it would be less efficient than using fertilizer. Phosphorous you can’t get out of the atmosphere so we might not have an easy out there.

Yes, there is, you rotate your crop with legumes. There are also crops that gather stable phosphorous and activates it, but those tend to be long-lived and thus bad for rotation.

What I don't get is why the focus on fertilizers? There may be some wisdom on not spraying random poisons on the stuff you are going to eat¹, but the worst you can get with fertilizers is soil salinization, and this is perfectly avoidable on any place that isn't a desert already, and there are ways to avoid it on deserts too, just a bit more expensive.

1 - So there's a reason for a poison by poison discussion, the overall label of "organic" just poisons the discussion.

I assume the focus is on ensuring long-term crop viability even if we manage to deplete easily accessible mineral deposits used to provide phosphates or whatever. Personally I say we liberate everything we can from the ground, including carbon.

How do the crops you mention “gather phosphorous”? From where?

Phosphorous is released from minerals by fungus in healthy soil. Tilling and chemical amendments, NPK fertilizers and biocides, kill fungus first.

If you learn about the soil food web you will learn that most things we dump on farmland are made available to plants by bacteria and fungi. Unfortunately, those are the things that we kill by farming the way we do.