Quote:Just don't have time to go into this more, so I will be brief. <a class="bbc_url" href='http://12.000.scripts.mit.edu/mission2017/fertilizers-2/'>http://12.000.scripts.mit.edu/mission2017/fertilizers-2/</a> seems to address what I am talking about.
"Prolonged fertilizer application decreases the humus (nutrient organic matter) content of the soil, consequently decreasing the filtration and water retention capacity of the soil [1]. This process occurs because the excessive usage of nitrogen-based fertilizers leads to a surplus of ammonium ions. The excess of ammonium ions contributes to soil acidification [11]...If the soil has low pH, it becomes more vulnerable to erosion [1]. Water leaks more easily through eroded land, so a soil’s filtration and water retention capacity is greatly reduced. Because water cannot be kept near the roots for long enough, plants grow more slowly and can even die. Acidic soil also has a high toxicity level. This implies that acids in the soil destroy important nutrients for plant growth, decreasing the humus content. Therefore, an over-fertilized field can quickly become unusable for agriculture [11]"
"For example, a long-term fertility trial conducted in Arlington, Wisconsin, revealed that after 30 years of nitrogen-based fertilizers, the soil’s pH was reduced from 7 to 4.8. Also, calcium and magnesium concentrations declined by 31% and 36% respectively. Calcium and magnesium are salts essential for plant growth, therefore such decreases in concentration make the humus almost unusable [12]."
"Farmers often apply more fertilizers and water than necessary because of the false belief that it would be more beneficial for crop yields [13]." (study 1998)
I do not think I have a complete understanding on the subject, but its fairly easy to see that A. We destroyed 300 years of topsoil in 30 years. B. Excessive Fertilization destroys soil quality. C. At least in the recent past (90's) farmers were engaged widespread in these bad practices. It also seems that fertilizers is responsible for great water loss when not applied correctly (leaching etc). Whether today methods of trying to preserve soil are working seem to be uncertain: <a class="bbc_url" href='https://www.nrcs.usda.gov/wps/PA_NRCSConsumption/download?cid=stelprdb1257757&ext=pdf'>https://www.nrcs.usda.gov/wps/PA_NRCSConsumption/download?cid=stelprdb1257757&ext=pdf</a>
I will concede that I can't find evidence easily that it 'requires' more water (other than fertilizer having much less water retention capacity). That may have been a misunderstanding on my part. But either way, I don't have time to dig it all up (haha, pun not intended, but I like it). I have no doubt that someone with professional farming experience could explain it better than I can or has a more complete knowledge.
No, that doesn't seem to address it actually. I asked you to explain your assertion that "fertilizer with mono-cultures" are destroying soil. You didn't explain anything to do with that. You just cited an article about the dangers of nitrogen over-fertilization.
There is a reason you can't Google up anything about mono-culture fertilizers, or any thing about fertilizer requiring more water. It's because there is no such thing in either case. You are misinterpreting these articles.
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Let's take these one by one.
About depleting the topsoil. It's true that when you crop a soil you use the nutrients in the soil. That's unavoidable and has been happening for a few thousand years. So when your article says farmers are depleting topsoil 10x faster than can be replaced NATURALLY (key word), what they mean is for the health of the soil you must amend it on an annual basis. In simple terms, you truck in about 2 tons/acre of a good compost with active biologicals every fall. Standard practice.
Again, I will point out, no half educated farmer in their right mind would pay $1-3 million for a tract of farmland, and then spend the next 20 years ruining the soil before they've paid off the loan. That's ludicrous. Every farmer would go bankrupt if they couldn't grow a crop and their land was also no longer worth anything. Think about it.
So no, the "farming system" is not completely killing all the soil and leaving large swaths of unusable land. Nor is it stripping all the topsoil off of large tracts of land and leaving barren wasteland. Land is too valuable in the U.S. and frankly it's very easy to fix.
I'll also ask, where is this wasteland of barren soil? Again I'll use my area as an example. The Central Valley has been farmed for well over a hundred years now. We have the worlds largest area of class 1 (the best) soil. Feel free to Google it. If we are destroying soil on a 20-30 year timeline how can that be? Where are all the barren fields? There are none.
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Onto "mono-culture" fertilizers.
What they are talking about is rotational crops vs mono-culture crops or what we would call row crops. In this area that's vines and almonds.
Rotational crops are when you grow a crop from seed for 1 season only, harvest it, plow it under, and the next year rotate it with a different crop and so on. That on it's own will leave you with healthier soil because you have varied plant matter being incorporated into the field each year, and they all carry different levels of different nutrients.
A mono-culture crop is one that is planted for 20 year - forever. Outside my window I'm looking at vines that were planted in 1918. They're still going strong by the way, no barren soil.
What the article is saying is with a mono-culture crop, incorporating the fields own waste materials in not sufficient to replinish all the soils needs. In vines for example, at the end of the season the leaves fall off and you disc them under the soil. That reincorporates a certain amount of nutrients into the field. In the spring, you prune the vine, shred the pruning and again disc them back into the soil. That again replenishes a certain amount of nutrients. But still that isn't sufficient.
Left only to that, the soil will suffer. Again, what they are stressing in a good soil amendment program added to that.
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Now let's address your link: <a class="bbc_url" href='http://12.000.scripts.mit.edu/mission2017/fertilizers-2/'>http://12.000.scripts.mit.edu/mission2017/fertilizers-2/</a>
When I first replied to you I stated I felt these things were more of an issue elsewhere, mostly in developing countries where ag education is poorer and there are much less restrictions.
I find it curious you quoted that wall of text but left out the very first line "Poor agricultural practices can cause serious problems for the environment. Prolonged fertilizer..."
Then later in figure 3 of the article they showed nitrogen fertilizer consumption by region. Which showed this country uses 6% of the global total while Asia as a whole is using well above 60%, South America 12%, and Central Asia 8%.
That sounds an awful like what I said. From your own link.
Again, I will restate, we monitor nitrogen applications very carefully so they do not leach into groundwater. We only apply what the plant is capable of uptaking. Also some common sense here: Why would I want to pay for extra fertilizer (it isn't cheap) to have it leach out of my root zone before it can be utilized? It's just not something that's done here. It also harms the plants in season by making them overly vegetative and less fruitful, so there is even more initiative to not overdo it.
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To move onto your lettered points.
A) We've destroyed 300 years of topsoil in 30 years: No, I hope I've sufficiently addressed this. If you have an issue with topsoil being artificially replenished with compost and other amendments that's fine. But that's not the same as saying it's being destroyed.
B ) Excessive fertilization destroys soil quality: Yes, continuously pumping large amounts of fertilizer, unchecked, for decades will ruin soil quality. That's well known and has been for a long time which is why it doesn't happen for myriad reasons I've already went into.
C) At least in the recent past (90's) farmers were engaged widespread in these bad practices: I'm not sure where you're pulling this from and if you're talking about U.S. Farmers or globally. You'd probably have to reach back to a very specific period from like 1975-1985 where we had both the means (fertigation) and lack of understanding to do that in the U.S. and call it widespread. We might be lowly farmers but we aren't total idiots that would willfully ruin our own soil and in turn, productivity, and in turn again, livelihood. I still can't really wrap my head around why you think anyone would do that.
As to your last point, I think you are again misunderstanding. Water not used by the plant is supposed to leach back into the ground. It is not lost by any means. It recharges the same groundwater supply we use daily. I think you're reading about water rention being deminished and interpreting that as we're losing water.
What the article is stating is water is not held in the root zone of the plant for as long a period. It drains quicker through the soil, it isn't lost. Meaning the plant itself has water available to it for a shorter period of time.
And finally, last point. Fertilizer cannot take more water because it does not have a root system
