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How a Solar Revolution in Farming Is Depleting Groundwater

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Re: How a Solar Revolution in Farming Is Depleting Groundwater

#61
post #52

Earlier quoted context omitted.

I did the math once and the amount of water we’ve pumped out of the aquifers worldwide and not replaced is worth more than a mm of sea level rise.

Please show the math and sources, I would love to see the sauce.

[dead]

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#62
post #21

The margins are doubtless so narrow that it's not feasible, but pumping during the day into a storage tank, and irrigating at night (while evaporation is relatively low) would be a way to slightly improve soil (though not aquifer) recharge. Certainly it would require less water volume , but again, the infrastructure costs for panels + submersible + storage are probably untenable in precisely the places this is needed…

Also, evaporation losses at leaf stomata can be adjusted with carbon dioxide.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#64
post #36

I know some farmers in North Texas where they are pulling water out of a depleted aquifer. The water is starting to get salty so they're adjusting to salt tolerant variants of their crops. The ground is also starting to drop due to the aquifer draining. It's crazy to see

I remember reading about how in the Soviet Union, there were places they were irrigating with brackish water and how they were now infertile. The obvious conclusion was that the Soviet economic system was busted to permanently destroy land for some temporary gain.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#65
post #36

I know some farmers in North Texas where they are pulling water out of a depleted aquifer. The water is starting to get salty so they're adjusting to salt tolerant variants of their crops. The ground is also starting to drop due to the aquifer draining. It's crazy to see

I remember reading about how in the Soviet Union, there were places they were irrigating with brackish water and how they were now infertile. The obvious conclusion was that the Soviet economic system was busted to permanently destroy land for some temporary gain.

The American equivalent is the dust bowl. The ancient equivalent is the desertification of Mesopotamia. Etc. etc.

Humans are bad at long term thinking.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#66

Earlier quoted context omitted.

If you don't irrigate during the day in hot climates some crops will die, and the yields will be terrible for most.

Doesn't that mean we should stop growing crops in such regions?

Permaculture maybe possible

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#67
post #34

Earlier quoted context omitted.

> If you don't irrigate during the day in hot climates most crops will die That is clearly not true. Most crops are fine with watering after sunset / before sunrise.

Fair. I just edited my comment because I combined two concepts and muddled them together. It's more common to suffer a poorer yield than total crop loss. But crops like tomatoes can die from lack of water during high heat days if the heat lasts for several days. Also, irrigating only at night (not just evening, but over night) can contribute to fungal and disease issues with some crops.

Sure, cucurbits and solanaceous crops and prone to humidity / water induced fungal attacks. Tomatoes are better watered at ground level (refer other thread about drippers) or even just flood irrigation.

Tomatoes are actually pretty robust, if you grow them properly.

The way I was taught to maximise survival / yield in hot climates is to grow as seedlings for a few weeks, until they're maybe 30cm or so tall. Dig holes ~ 25cm deep, flood / drain / flood / drain - and then take all but the upper few branches off the seedling, and plant, backfill with soil, so about 5m is above-ground.

Because they have adventitious rooting you've effectively just given them a massive reservoir of water retention. This is obviously expensive at scale (though not intrinsically infeasible) but works superbly well in hostile, arid climates.

I expect the next decade or two will force a lot of changes to the way food is grow in already marginal climates.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#68
post #52

Earlier quoted context omitted.

I did the math once and the amount of water we’ve pumped out of the aquifers worldwide and not replaced is worth more than a mm of sea level rise.

Please show the math and sources, I would love to see the sauce.

There’s a calculator that works out how many acre feet of water it takes to raise the ocean level, and the UN has estimates on total global aquifer depletion. There were a couple ways to calculate it. I’ll see if I can reproduce my work.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#69
post #38

Earlier quoted context omitted.

> These are also expensive to buy & run. Long-term, it’s the cheapest option if you want to farm in an arid region.

Drip is used quite a bit in Northern California for higher value crops like tomatoes, but it's too expensive for normal crops. It also seems like a non-starter for smaller scale and poorer farmers in developing nations; that's a lot of CapEx for generally lower value crops.

> that's a lot of CapEx for generally lower value crops.

We’re not disagreeing. Those farming regions are not viable long term unless the economics change dramatically.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#70
post #36

I know some farmers in North Texas where they are pulling water out of a depleted aquifer. The water is starting to get salty so they're adjusting to salt tolerant variants of their crops. The ground is also starting to drop due to the aquifer draining. It's crazy to see

Is it close to these huge sinkholes in Turkey? https://www.dailysabah.com/gallery/turkish-farmers-worry-abo... Because these in Texas seem tiny in comparison https://www.texastribune.org/2023/08/16/texas-drought-heat-a...
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