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The cost in buying fertiliser and applying it is not always justified by
even the short-term returns, that is it is applied in excess of the optimum
in some cases for reasons other than being demonstrated to be cost
effective. OTOH I know of no analysis that shows we could feed the world's
population by organic methods. There may be some focus on this issue over
the next few decades as sources of mineral phosphorus compound become
exhausted and the cost of nitrogen fixing rises with energy costs.
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I'm not sure what exactly you're getting at here. How is the cost of buying fertiliser not justified by the short term returns? I also don't understand your take on phosphorus as there is plenty sitting in soils all over the world already.
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Soils having such high levels of soil phosphorus no longer need to be fertilised with more than the amount of phosphorus removed in harvest. In fact, many agricultural soils in industrialised countries with long histories of phosphorus build-up from manure or fertilizer application have accumu*lated so much available phosphorus that little if any additional phosphorus is needed until phosphorus is drawn down to more moderate levels over a period of years.
Professor Stefano Grego
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Surely we can either harvest it, or implement solubilising bacteria to help break down the unavailable forms of P. How can there be a P shortage, even in a few decades, when there is so much in the land already?
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Land always needs rotation, especially so if you grow a monoculture. This
is not limited to where chemical fertilisers have been applied.
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Land still needs to be rotated because of high application of fertilisers building to toxic levels... particulalry P (locks out iron). Ah, maybe rotated is the wrong word, easy to confuse with ordinary crop rotation I suppose. So let's just say land is left unusable for certain periods of time.
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Dare you explain the connection between the state of soil bacteria and
humans poisoning themselves by employing poor food handling practices?
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Bacteria is a very basic form of life, capable of genetic shifts that will change it from one thing into another. we eat e.coli all the time. our stomach acids kill it usually... but something is causing to e.coli to become virulent, and it is becoming virulent with greater frequency. There are some that suggest this is down to artificial fertilisation by man. The reasoning being, I believe, that the fertilisation is killing off the friendly bacteria and fungi, the beneficials... it is killing them off because they haven't anything to do. This shift is having a knock on effect with the bad microbes which is why we're seeing more cases of virulent e.coli.
I'm not sure i agree with this, but it does make some logical sense so I cannot discount it easily.
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Please provide some evidence for that claim. What are the costs of that
method compared to others? How do you feed cattle or sheep hydroponically?
Would that be cost effective?
David
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I meant only in regards to crop farming. Leaving the land alone for a while would leave plenty to feed cattle or sheep. we could also still crop farm, only doing it organically, at least more intelligently. cash crops could be left to sterile hydroponic growing. Hydroponic systems may be expensive to set up but are not very expensive to maintain. If built in the right way you can have hydroponic systems that run with minimal power. All it takes to keep enough o2 in the water is the continual motion of that water.