Soil Replenishment in drought and high heat and high humidity
- Thread starter Meadowlark
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You must be joking!
I grow sweetcorn in SW Scotland every year, & there's no way you can buy any as good.
Like peas, as soon as it's taken from the plant, the sugars start turning to starch.
They CANNOT be as good as home-grown, & I've never tasted one that is.
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We absolutely agree on that, Headfullofbees.
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That makes it worthwhile to me to continue posting here. Thank you.
To me it is a matter of simple math of addition and subtraction. The soil only has so many minerals, some is plant available and the others are locked up in a different form which might be broken down in the future for the plant to use by microbes.
If you grow something like corn in a spot and then harvest the corn, then what you took out is subtracted from the soil because the corn plant pulled up that certain amount of nutrients. If you decide to pull up the stalk too instead of tilling back in, then whatever nutrient the stalks used is no longer available in the soil. So you have to add those back to the soil in some manner whether it is compost or regular fertilization of organic or synthetic fertilizers or cover crops. Here is an ideal of what corn kernels use up.
If you grow something like corn in a spot and then harvest the corn, then what you took out is subtracted from the soil because the corn plant pulled up that certain amount of nutrients. If you decide to pull up the stalk too instead of tilling back in, then whatever nutrient the stalks used is no longer available in the soil. So you have to add those back to the soil in some manner whether it is compost or regular fertilization of organic or synthetic fertilizers or cover crops. Here is an ideal of what corn kernels use up.
That's how it seems to me too.
So for example, if leafy greens are rich in iron then you'd think it would be vital to put iron rich organic matter back into the soil. But I'm not sure that's the case.
When it comes to fossil fuels (as an analogy) we know that we've extracted and burned millions of years worth of stored energy from the sun (fossil remains of billions of trees grown using the sun's energy over millions of years) in a few short decades.
How long (for example) can we grow leafy greens in a field before we've used up all the iron in the soil? If we feed the soil life with green manures, compost etc does it matter whether or not there's iron in those manures/composts?
My understanding is that the only way the iron will be replaced (other than by letting the vegitable matter rot back down) is from break down of new rock into soil .... a process that takes a VERY long time. So, can the natural process of rock breaking down into soil keep up with the rate at which we're stripping minerals from the soil when we harvest our vegetables?
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Rich in iron is a comparative term, 100grs of spinach has under 3 mg of iron in it. I suppose the amount in the ground varies, but round here there is enough they used to make cannon with it. Unlikely to run short.
Right. Something rich in iron doesn't mean tons of it. It is a micronutrient so very little is still taken from the ground, but yes it will have to be replenished at some point.
If your talking about a natural process of replenishing iron then I'm not sure of what types of iron is in the soil. Iron oxides from rock is a possibility. A bird flying by and pooping on the soil is natural and would contain some iron. Insect activity (ants, termites) may also carry some form of iron to your location.
A soil test before and after harvest would answer both of those questions.
you are correct. but is iron an essential part of growing/gardening?
Yes but in small quantities. If you are asking if a tomato or something can create a fruit with zero iron, I'm not sure but that is about impossible to test that since most soil and potting mixes contain some iron. The pH is most relevant in the case of iron uptake.
Have you ever seen a blueberry bush that was planted in a high pH soil. The leaves will yellow with green veins and growth suffers. That is the best example I can give of a plant not gettting enough iron.
I just used iron as an example off the top of my head.
The point I was making is in relation to all minerals.
Any plant or vegetable is made mostly from the sun's energy. But the traces of minerals come from the soil.
If you keep harvesting crops from a field without replacing the traces of minerals how long before there aren't enough minerals in the soil to grow your crops. Or, how long before they're lacking in nutrients? I
I expect compost made from a wide variety of organic matter has enough minerals. But what if you used the Ruth Stout method and only put hay on your soil? Minieral rich veggies coming out each year and only hay going back in.
I's a rhetorical question really. Just pondering over the whole issue of sustainability.
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There is also precipitation, by the time a rain drop has fallen far enough to hit the ground it has picked up a fair bit of stuff. Of course some of it simply comes as dust, think of archeologists excavating ancient ruins, all that material on top came from somewhere.