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 most (and where the impacts of depleting the water table will hit the most).
Or, irrigate during the day but use sub-surface drip irrigation. [1]
Drip systems tend to require a) a lot of pressure, and b) a very consistent pressure, to get reliable output. These are also expensive to buy & run.
Drip or leaky-hose type underground systems are difficult to maintain (I've tried!) just because you can't see them. The way you find out something's wrong is usually because a plant or an area is looking very very happy, and other plants / areas are dying off.
Under-mulch is good, but doesn't lend itself to broadscale cropping as described in TFA.
Long-term, it’s the cheapest option if you want to farm in an arid region.
We’re not disagreeing. Those farming regions are not viable long term unless the economics change dramatically.
That’s the vast majority of current farm acreage in the world.
That is clearly not true.
Most crops are fine with watering after sunset / before sunrise.
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.
Its a much more complex problem though. Most farms in the US depend on debt and subsidies to get by. That money comes with strings attached, from the yield required to cover expenses to subsidies that require mono-cropped fields that basically sit idle in the off season or when a crop fails.
There are different techniques that could be used, but none of them will match the sheer tonnage of yield from a mono-crop drenched in fertilizer, herbicides, and laid out in a way that allows for massive tractors and combines to be used. All of these methods cause huge damage to the land, but again I'd argue we've left those farmers with little to no choice in the matter given how our food system is designed.
But in the Fresno/Bakersfield area of California, with only 5-10” if rain per year, over pumping is making farming uneconomic. See SGMA https://en.wikipedia.org/wiki/Sustainable_Groundwater_Manage...
Sure, but almost all the countries TFA mentions are generally farmed by small landholders, so irrigation via stored water is not infeasible. The mammoth style broadacre tiny-return-per-hectare, heavily mechanised, fertiliser- and insecticide- reliant style agriculture popular in the USA isn't so common in these places.
The 'dent in the aquifer' you mention (and TFA dwells upon) is because there's thousands of people doing the same thing at the same time to the same aquifer for years on end.
Regrettably TFA doesn't talk volumes, other than three mentions of 'cubic miles'.
Apart from an exasperated 'why do they use anything but metric?' sigh, it's also obviously a heavily aggregated figure across large geo regions.
These small holdings with their panels + pump per field, pulling from an increasingly deep water table, are presumably extracting probably in the range of 10-20 kilolitres of water per day - the size of an average plastic water tank that has a one-off cost about the same as a submersible DC pump + panels. (Lined steel, concrete, etc, become more attractively priced at larger volumes.)
So, yes, absolutely, if your geography allows, then put in a megalitre+ sized hole in the ground up-hill, cover it to reduce evaporation & algae, fence it to prevent animal damage, etc. Happy days.