It's not that infinite without a way to refresh protein, such as mining ammonia, eventually you run out of soil resources and crash. It's got a hard limit, so to speak.
Yeah if you turn people who die into fertilizer and process all of their excrement you can probably sustain the fields they eat from. Can't argue with that.
That alone is still not infinite. When you eat food you're taking the nutrients that you need out of it and excreting what is left. So even if all of your shit went directly to manure then you're still putting in less than you took out.
The energy input is the sun, and most of the calories come from the air (carbon dioxide). Given so much external input, harvesting from a plot without reducing soil fertility is totally possible. With nitrogen-fixing crops (soybeans being the poster child), even the nitrogen fertilizer comes from the air.
The plants use energy from the sun to turn carbon dioxide from the air into edible calories. When our animal bodies "burn" the food we eat, that turns it back to carbon dioxide, which we exhale.
not a scientist here, but i imagine it's a combination of different forms of energy/material and how different organisms utilize them. Plus the basic fact that nothing is ever perfect. We consume food, a lot of those nutrients are burnt for energy. Our brain consumes a significant majority of what we eat. Stuff has to go somewhere for things to happen.
That's like counting tigers in the zoo as tigers in the wild. Dust from homes gets put in landfills, corpses get burnt or buried in boxes, human excrement gets treated and reintroduced to streams. It's not finding its way back to the fields in such a way that it's 100% efficient, not even close.
Not all the matter in farming fields come from fertilizer. A lot of it comes from CO2 in the air, which will eventually go into some plant that we can eat. Also, all those ways that matter is lost, therefore not being 100% efficient doesn't make matter disappear. Burning turns it into CO2 -> it will reach a plant. Excrements going into water streams -> plants will pick them up, or ocean wildlife will pick them up. Buried corpses -> microbes and plants will pick them up. The only way to "lose" matter is for it to leave the atmosphere into space or to be buried so deep that no life can reach it.
The atmosphere loses matter at a rate that is (presumably) not affected by human actions.
Matter buried too deep is compensated by matter coming out from volcanic eruptions.
As long as the earth's core is hot enough for volcanic activity and the sun doesn't run out of fuel, the cycle keeps going.
Like other epiphyte orchids, the roots of Phalaenopsis roots are covered with a spongy epidural tissue called “velamen.” Just a few cells thick, velamen helps orchid roots absorb water and nitrogen from the air.
It's probably my favorite plant. Hardy as hell despite a bad reputation for being picky. People don't realize they just go dormant until Spring.
At between 20 to 300 lbs per acre, yes. Generally most legumes will need 60 lbs per acre, so most will be self sufficient in ideal weather.
For 60 bushel per acre soybeans still require fertilizing with monoammonium and diammonium phosphates, as well as ammonium acetate, and to go beyond 70 bushels consistently supposedly does require supplemental nitrogen although this has yet to be recreated in studies.
And where did the Dinos get the poo from? From eating plants. Plants that either used bioavailable nitrogen or captured nitrogen from the air.
The nitrogen cycle has been interconnected between soil, air and biomass nitrogen since forever. There simply is no fundamental need to use mineral fertilizers, as was claimed in a comment earlier.
In a different form than they do now. We have, and still do, genetically modified them to their current and future state. We've been selectively choosing and breeding plants for many millennia. Corn, beans, and tomatoes didn't much look like what you buy in the store today.
So, how did they survive? Plants grow, plants die, and the rotting plant material gets returned to the soil. Add in a few dead critters, a bit of fire, and some rain, and Baby you gotta stew going!
We still do that even today. Gardeners often compost things like food scraps to grass clipping to create small scale "natural" fertilizers and work that into their gardens.
If you are a 'Murican you will have been taught that Native Americans taught the Pilgrims how grow food and hunt. Because you know, them Pilgrims was a bunch of City Slickers that didn't know how to survive in the "wild". There weren't no Piggly Wiggly's or Aldi's around. They were taught how to grow the Three sisters - Corn, beans, and squash together for best yields. The beans, (legumes), fixed some nitrogen into the soil, the squash plant provided shade cover to limit the growth of "weeds" that could choke out the plants you did want and to hold moisture and keep the soil cooler so the corn, and beans would grow better. The Native Americans also understood, that adding some dead animal matter will also boost your yield. As did most any early farmers.
These days, we need to grow food crops on a very large industrial scale. And yields need to be vastly increased to provide enough for everyone to eat. To do that we need to create better varieties of plants that can withstand the high growing stresses from high density planting with more disease and bug resistance all while producing greater and greater yields. This does require the added use of fertilizers and even pesticides to reach the desired yield goals.
We don't need industrial farming to feed the world. We need industrial farming to provide excess amounts of meat and dairy products and sustain an abhorrent food waste.
In western countries half to two thirds of farmland are used for animal feed. by reducing our meat overconsumption by half, which would still far exceed what is considered a healthy diet, we could make 25% of farmland available for feeding humans. 30-40% of food in the US is wasted. About 10% of food in the EU is wasted. So if the US would reduce its food waste to European standards that would make another 20-30% of farmland available.
So simply by cutting down overconsumption and food waste, we could increase the available farmland by 50% and accept 2/3s of current yields per hectar in the US w.o. any reduction in available food. When looking at farmers who switched from industrial to more sustainable farming, they achieve the same and sometimes increasing yields, as the crucial natural ability is restored with a healthier soil and more biodiversity, protecting against all sorts of pests and allowing for pollination.
Industrial farming is a death sentence to the world, as it destroys the very foundation of farming. An intact soil and an intact ecosystem to allow the plants to grow.
In the yield size we see, they didn't. That's the point. Food crops cannot sustain the current human population. Before humans came along an area had a variety of plants which did not have their stalks and fruit systematically harvested and transported elsewhere. They grew in the ground and their produce would rot where it landed, enriching the soil.
I don't think "Food crops cannot sustain the current human population" is the most accurate. I think adding on an "indefinitely" or something similar would be more accurate. The problem is that there's plenty more land and resources that could go to crops, but it's more of a problem of how sustainable it is long term.
Topsoil erosion could outpace soil conservation especially with synthetic fertilizer, but if people aren't getting food now or in our lifetime then it's not caused by an inability to grow enough crops. It's caused by companies being driven by the profit motive. It's more profitable to let food go to waste than get it to people who can't afford it.
Currently the technology is there to make more than enough crops for everyone, but how sustainable that is in the long term is not something that has been a priority. If more effort is put into making factory farming actually sustainable, which is the way things are starting to go although pretty gradually, then the only thing stopping people from getting food is the incentive to destroy/ let it rot rather than take any potential loss from not artificially inflating prices
How about this correction, then: "Food crops can only be sustained for some period of time at which point it won't affect me and in that case it might as well be 100% sustainable because I completely lack empathy or attachment to humanity."
Echoing malthusian sentiments of "there's not enough food for everyone" is not helping anyone.
Pointing out the actual problem which is that big farms that exist right now aren't there to get food to people they are there to make money and they don't care if it's sustainable or if anyone gets to eat, is what I did. You're the one glossing over that.
I have accurately assessed the problem that you are attempting to ignore, I gave no potential solutions but if you want one then just reduce meat consumption and production (preferably through regulations and tax incentives) which will reduce crop usage by maybe 20-30%.
Even in a perfect socialist utopia without greed The Fields Are Not Sustainable. If human population stays where it is or grows again then there will be no other solution than reducing the population through child policies or similar measures, or famine will be inevitable.
Despite your fantasy world, the fields are not sustainable.
I disagree with that. In Western countries typically half to two thirds of agricultural land are used for meat and dairy production. We have plenty of food available to sustain the current or even growing populations without depending on mineral fertilizers. Farming techniques have significantly evolved over the past two hundred years and the crop yield of an intelligently managed field without mineral fertilizers is not signficantly lower than what is achieved by conventional farming. With the added difference that conventional farming is actively destroying the soil and killing the insects that are vital to maintaining agriculture.
So you're saying that agricultural practices need to change to make is sustainable but you also disagree that it isn't sustainable? It doesn't sound like you disagreed at all, mate.
Modern industrial farming is not sustainable for the next hundred years, no, but there are a lot of levers to work to transform it into something that will reliably feed future generations.
One lever is amount and kind of meat in the average diet. It takes something like seven pounds of grain to make one pound of beef. Modern chicken breeds are amazingly efficient at converting feed grain to chicken meat, but even they are something like two pounds in to one pound out. Reducing the percent of meat in our diets would make our food go significantly further.
Bacteria take it out of the atmosphere slowly. It's a certain rate per land, and due to the coastline paradox we know that the area of land is infinite.