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Negative effects of synthetic fertilizers  RSS feed

 
Scott Stiller
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Hello friends. We are all aware of the larger problems with using synthetic fertilizers. What I'm interested in is what if,anything gets out of balance when using them. Thank you
 
John Polk
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Many synthetics are loaded with salts.
 
Freya Bennett
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Scott Stiller wrote:Hello friends. We are all aware of the larger problems with using synthetic fertilizers. What I'm interested in is what if,anything gets out of balance when using them. Thank you

Well, using too much nitrogen fertilizers too close to harvest may result in nitrates accumulating in produce. Also, phosphates can leak into water reservoirs and cause abnormal blooming.
I hope it helps, or did you mean something different ?
 
Shawn Harper
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I am pretty sure it kills worms when used in normal sized dosages...
 
Casie Becker
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Whatever the particular mechanism, synthetic fertilizers lead to a soil that lacks the full suite of life forms that support the health of the plant. They don't receive all the important nutrients that aren't in the chemical fertilizer.

Soil life holds nutrients to be used as neccessary, whereas chemical nutrients can wash away or become unaccessible to the plants after they are applied. Both wasted effort for the farmer and pollution to the environment.

Another area where I don't understand the mechanism, but recognize it exists, is how the soil life helps the plant develop defenses against disease and pests. Chemical fertilizers can't replace these mechanisms. Chemical dependent plants are less resistant to disease and pest pressures.

I keep looking at this question and finding it too big to provide a complete answer to. I don't know whether synthetic fertilizers are straight out poisoning the soil life (bacterial, fungal, and small animals) or if they're simply breaking the cycle where the plants provide nurishment to the soil life and causing it to starve out. Continual application of chemical soil has repeatedly been shown to degrade the quality of the soil (many times to the point of desertification). I've never heard of soil biology having this affect.
 
r ranson
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Freya Bennett wrote:
Scott Stiller wrote:Hello friends. We are all aware of the larger problems with using synthetic fertilizers. What I'm interested in is what if,anything gets out of balance when using them. Thank you

Well, using too much nitrogen fertilizers too close to harvest may result in nitrates accumulating in produce. Also, phosphates can leak into water reservoirs and cause abnormal blooming.
I hope it helps, or did you mean something different ?


This is a good point and one I've wondered about.

There's not enough study done in this area yet, but I've noticed with my sheep and goats that there are many plants that are considered toxic to feed the animals. These same plants were primary fodder for these livestock a little over 70 years ago. mangelwurzels, for example, were the primary winter feed for sheep for several hundred years. Now they are considered dangerous, especially the leaves because of the high nitrate content can damage their heart. When grown organically, there is almost no danger to feed mangelwurzels to sheep - it's only when grown with synthetic fertilizer does this danger happen. Same too with many other traditional fodder crops.

If it makes such a strong difference in livestock, I wonder what difference it makes to people.

I'm only just now learning about these fertilizers. Luckily I was raised to grow things organically. When I learned I could buy fertilizer I couldn't understand why anyone would want to throw away their money. Soil fertility can be achieved through other means, besides all that crop residue and compost has to go somewhere, why pay someone to take it away? I often wondered if this is what they call an 'idiot tax', like speeding tickets. People volunteer to throw away their money. It's only in the last few years, I'm starting to understand how widely used these chemicals are and what damage they can do.
 
Julia Winter
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Casie Becker wrote:
I keep looking at this question and finding it too big to provide a complete answer to. I don't know whether synthetic fertilizers are straight out poisoning the soil life (bacterial, fungal, and small animals) or if they're simply breaking the cycle where the plants provide nurishment to the soil life and causing it to starve out. Continual application of chemical soil has repeatedly been shown to degrade the quality of the soil (many times to the point of desertification). I've never heard of soil biology having this affect.


That's an excellent point. Even if the chemicals in the fertilizers don't directly poison the soil life, by offering "junk food" to the plants they break into and break down that complex web of exchange, where plants trade "cookies and cupcakes" (that's what Elaine Ingham calls it - it's carbohydrates they create from CO2 via photosynthesis) for specific minerals/nutrients from bacteria, from fungi, from other life in the soil. If the plants aren't feeding the soil life because they are sitting in a (temporary - until the next strong rain event) solution of nitrogen phosphorus and potassium, then maybe that's what kills the soil food web.

As in most things, it's probably a combination of factors. And the solution, as in most things, is to develop a complex polyculture, with active human management to cut back the thug plants and let them feed the favored plants. Or, in the case of broadfield crop production, the solution is to develop a diverse population that can be seeded into the field to support your main crop.
 
Carl Trotz
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Whatever the particular mechanism, synthetic fertilizers lead to a soil that lacks the full suite of life forms that support the health of the plant.


Yes, because they are salts, they bind with water molecules, and actually pull water out of microorganisms - like putting salt on a slug to kill it. (Not that I've ever done that - but I saw it done when I was a kid.) How much a soil can take before serious harm is done will of course depend, especially on how much organic matter is there to buffer it. Better to do no harm.

The protective power of soil microbes comes largely from the crowding-out effect. Bacteria and fungi in a healthy soil will cover every square micrometer of a plant's surface - root, stem, and leaf - feeding on the plant's exudates. This means there are no infection sites open for pathogens. If that layer is killed off, or if you lack the healthy soil food web to begin with, the plant is defenseless.

Besides crowding out pathogens, microbes are necessary for nutrient cycling; those bacteria get eaten by protozoa, which then release nitrogen - and whatever else the plant needs - as a waste product. Fungi will be eaten by nematodes and micro-arthropods to the same effect. All a very delicate balance that can take some work to achieve. Putting fertilizer salts on the soil can only move you away from that balance.

I remember in my youth when a bag of 20-20-20 fell off a tractor and split open at the edge of a field. Even the weeds within twelve inches of that pile of blue fertilizer soon turned brown and died. It remained a dead spot for a couple of years. That spoke to me.
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